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Children Dysautonomia information geared toward children can be found at: The Children's Heart Institute: http://www.childrensheartinstitute.org/ Dysautonomia Youth Network of America: http://www.dynakids.org Nationwide Children's Hospital: http://www.nationwidechildrens.org/postural-orthostatic-tachycardia-syndrome-clinic Children's Hospital of Chicago: https://www.luriechildrens.org/en-us/care-services/specialties-services/center-for-autonomic-medicine/diagnosis-treatments/Pages/inpatient-outpatient-treatment.aspx Chronic Illness Rest Ministries: http://www.mychronicillness.com/ Disability Social Security Administration's Adult listing of Impairments: https://www.ssa.gov/disability/professionals/bluebook/AdultListings.htm Social Security Administration's Childhood Listing of Impairments: https://www.ssa.gov/disability/professionals/bluebook/ChildhoodListings.htm Apply for Social Security Online (Adult): https://www.ssa.gov/disabilityssi/ Apply for Social Security Online (child): https://www.ssa.gov/disabilityssi/apply-child.html Disability Secrets: http://www.disabilitysecrets.com/ Florida Woman Claims she was Unfairly Denied Unum Payments: http://www.chattanoogan.com/articles/article_29001.asp National Organization on Disability: http://www.nod.org Online Lawyer Source http://www.onlinelawyersource.com/social-security-disability/index.html Employment Job Accommodation Network: http://janweb.icdi.wvu.edu/ U.S. Department of Labor Office of Disability Employment Policy: http://www.dol.gov/odep/ Medical Bills Giving a Chance Foundation (for members with Chiari I Malformation, Syringomyelia, Basilar Invagination, Tethered Cord, Ehlers Danlos, Hereditary Disorders of the Connective Tissue, Pseudotumor Cerebri, etc.) http://www.givingachance.org/ Medication Find prescription drug programs for which you may qualify: https://www.pparx.org/Intro.php Transportation Air Care Alliance: www.aircareall.org Angel Flight: www.angelflightamerica.org The National Patient Air Transport Helpline: http://www.patienttravel.org/ *This page is a work in progress. New links will continually be added. If you would like to volunteer to find links to add to this page, please let us know .

What is Neurocardiogenic Syncope? Neurocardiogenic syncope is a temporary loss of consciousness associated with a drop in arterial blood pressure, quickly followed by a slowed heart rate (Grubb & McMann, 2001, p. 133). Neurocardiogenic syncope (NCS) is also referred to as vasovagal syncope or neurally mediated syncope. The terms are used interchangeably throughout this web page. What are the symptoms of NCS? Neurocardiogenic fainting usually occurs while standing. Emotional stress, stressful condition and pain may trigger an episode, especially among the young (Shah, Gupta & Lokhandwala, 2003). The onset may be abrupt or associated with warning symptoms such as fatigue, weakness, nausea, sweating, pallor, visual disturbances, abdominal discomfort, headache, pins-and-needles, lightheadedness or vertigo (Deering, 2003). Presyncopal patients may also complain of palpitations, vomiting, disorientation, and difficulty speaking clearly or coherently (Grubb & McMann, 2001, p. 60.). Other symptoms that may present before a faint include feeling either warm or cold, tremors, yawning and having a bluish/purple or red coloring to the skin (Alboni, Brignole, Menozzi, Raviele, Del Rosso, Dinelli, Solano & Bottoni, 2001). During the faint "seizure-like" activity may occur (Grubb, Gerard & Roush, 1991). This convulsive activity is thought to be distinct from a seizure disorder. Patients are sometimes symptomatic after a faint as well. Patients may complain of symptoms including nausea, clamminess, lightheadedness, headache and malaise (Deering, 2003). Patients may also experience vomiting, abdominal discomfort, weakness, tremors, cold or warm feelings and confusion (Alboni et al., 2001). Patients who experience frequent neurocardiogenic syncope may report symptoms between faints as well, such as chronic fatigue, headache, chest pain, exercise intolerance, heart "flip flops" and an inability to tolerate prolonged standing. Mechanisms and Causes of NCS When a person stands up, the pull of gravity causes blood to pool in the lower extremities. This can result in a lack of blood supply to the upper body, including the heart and brain. Normally, the body automatically adjusts to the lack of blood supply by increasing vascular tone, heart rate and cardiac output. Blood vessels contract, heart rate increases, systolic blood pressure remains about the same or drops slightly while diastolic pressure rises slightly (Brunner & Suddarth, 2000, p. 546). In those with neurocardiogenic syncope this compensatory mechanism does not always work correctly. The exact mechanisms of NCS are not completely understood, and several theories have been proposed. Many physicians hold a general consensus as to what is happening during NCS as follows: The strong contractions of the ventricle walls are thought to cause a response in the mechanoreceptors, which misinterpret what is happening and send a message to the brain that the blood pressure is actually high. In response, the sympathetic portion of the cardiovascular center reduces its impulses to the heart and blood vessels while the parasympathetic division increases its impulses (Grubb & McMann, 2001, p. 61-62). This abnormal nervous system reflex causes the heart to slow and the blood vessels to dilate (open up), further lowering blood pressure (North American Society of Pacing and Electrophysiology, 1999). Because of this faulty adjustment, NCS patients may experience intermittent fainting. A 2004 research publication suggests patients may awaken from sleep with symptoms of forthcoming neurocardiogenic syncope (Krediet, Jardine, Cortelli, Visman & Wieling, 2004). This suggestion may seem to contradict current teachings on this disorder. However, research shows that transient autonomic mechanisms that predispose to vasovagal syncope may occur during sleep (Shneerson, 2000, p. 1-15). Findings from a 2008 neurocardiogenic syncope study seem to contradict current beliefs regarding what happens during a fainting episode as well. The results did not show an increase in ventricular contractility before tilt-induced syncope, or in presence of a valuable increase of sympathetic activity. Instead, the researchers observed a reduction of atrial contractility, which they believe may be a contributory component in the pathogenesis of vasovagal syncope . There are several other factors that may be contributory components in the pathogenesis of vasovagal syncope as well. Differential changes in plasma levels of epinephrine, renin, endothelin, vasopressin, cortisol, prolactin, beta endorphins and substance P have been reported by some investigators either prior to or during a syncopal episode in patients with vasovagal syncope (Ellenbogen, Morillo, Wood, Gilligan, Eckberg & Smith, 1997). Further research has shown that galanin may play a role in one's ability to adapt to orthostatic stress. Patients may have a genetic susceptibility to NCS as well. Some researchers have suspected that serotonin might be involved in the pathogenesis of NCS. Studies in animals have shown that the withdrawal of sympathetic impulses correlates with a higher level of serotonin being present in the central nervous system, the brain and the spinal cord (Grubb & McMann, 2001, p. 57). However a later study of NCS patients found no differences in serotonin activity at the time of fainting, but did show a lower serotonin level in patients during the early phase of tilt table testing (Mitro, Hijova & Mudrakova, 2006). Another study showed that young women who had vasovagal syncope with a positive tilt test result had a greater sensitivity to insulin. Insulin, in addition to its known metabolic effects, has sympatho-excitatory and vasodilatory actions on muscular blood vessels. The authors of this study conclude that insulin hypersensitivity could be one of the predisposing factors for vasovagal episodes (Ruiz, Calvar, Hermes, Rivadeneira, Bengolea, Chirife, Tentori & Gelpi, 2003). How is NCS diagnosed? Tilt table testing is often used to diagnose NCS. However, tilt table testing can have false-negative and false-positive results (Levine, 1999). How is NCS treated? There are a variety of non-pharmacutical methods used to control and prevent neurocardiogenic syncope. No single therapy has been found to be effective in all patients. Non-pharmacutical therapies used to treat NCS include the following: Cardioneuroablationreportedly has helped some neurocardiogenic syncope patients, although the study reporting this was small and patients had only been followed up for 9 months at the time of publishing (Pachon, Pachon, Pachon, Lobo, Pachon, Vargas & Jatene, 2005). Further investigation is warranted. Counter-maneuvers may help some patients with neurocardiogenic syncope. Research has shown that physical counterpressure maneuvers are a risk-free, effective, and low-cost treatment for patients with vasovagal syncope and recognizable prodromal symptoms, and should be advised as first-line treatment in these patients (van Dijk, Quartieri, Blanc, Garcia-Civera, Brignole, Moya & Wieling, 2006). Isometric arm counter-pressure maneuvers can increase systolic blood pressure and prevent fainting in some patients with NCS (Brignole, Croci, Menozzi, Solano, Donateo, Oddone, Puggioni & Lolli, 2002). Patients can perform isometric arm counter-pressure maneuvers by gripping one had with the other and pushing both arms away from their chest. Leg crossing combined with muscle tensing at the onset of prodromal symptoms can postpone, and in some instances prevent, vasovagal syncope (Krediet, van Dijk, Linzer, van Lieshout & Wieling, 2002). Sitting with the head between the knees often is an effective means of preventing syncope (Mathias, 2003). One patient has reported success in warding off a fainting episode by gently but briskly stepping in place for a short time, bringing the knees a little upward and puffing out the exhale with each rep. Pumping the arms and fists during this counter-maneuver has helped her as well. Increasing dietary salt and fluid intake may help prevent symptoms associated with neurocardiogenic syncope (Bloomfield, 2002). Orthostatic self-training and tilt training may help select patients with NCS (Abe, Kondo, Kohshi, Nakashima, 2002). It is of greatest benefit to younger patients and those who faint frequently (Zeng, Ge, Zhang, Wang, & Guo, 2008). Orthostatic self-training involves standing against a wall, without moving, twice a day for a planned duration of up to 30 minutes. The results of orthostatic self-training studies have been mixed, with one study concluding it ineffective in reducing the positive response rate of head-up tilt test in patients with recurrent neurally mediated syncope (On, Park, Huh, & Kim, 2007). Tilt training involves inclining patients on a tilt table each day. Some patients have to continually be inclined for this therapy to be effective. This therapy will not be effective in all patients. However, one study showed that in 19 patients who abandoned tilt training after about 1 year, none of them reported fainting during daily life. The authors of this study hypothesize that the disturbed autonomic reflex activity may have been restored in these patients (Reybrouck, Heidbuchel, Van De Werf & Ector, 2002). Paced breathing may help to prevent vasovagal syncope induced by head-up tilt test. Researchers who studied the effects of paced breathing believe respiratory training could be useful in the prevention of vasovagal syncope (Jauregui-Renaud, Marquez, Hermosillo, Sobrino, Lara, Kostine & Cardenas, 2003). Removal or avoidance of agents that predispose to hypotension or dehydration can lessen the occurance of neurocardiogenic syncope (Bloomfield, 2002). Situations that can predispose an individual to syncope are listed on the POTS Place "What to Avoid" page. There are a variety of medications and medical treatments that may help prevent neurocardiogenic syncope as well. These include the following: ACE inhibitors may prevent NCS, presumably through inhibition of sympathetic system activation and the peripheral hypotensive effect (Zeng, Zhu, Liu, Hu, Wang, Yang, Wang, He & Tan, 1998). Alpha-agonists increase venous tone and decrease pooling, which may prevent activation of mechano-receptors. They also counteract the arteriolar vasodilation produced by the triggering of the vasovagal reflex (Raviele, Themistoclakis & Gasparini, 1996, p. 115). Midodrine is an example of an alpha-agonist that is used to treat NCS. Midodrine has been shown to significantly improve orthostatic tolerance during head-up tilt in patients with recurrent neurally mediated syncope (Kaufmann, Saadia & Voustianiouk, 2002). Researchers have also found Midodrine to be effective in both treating and preventing vasovagal syncope in children (Qingyou, Z., Junbao, D. & Chaoshu, T., 2006). Beta blockers have been reported in many studies to be effective in treating neurocardiogenic syncope. Presumably, these agents exert their effects through their negative inotropic actions, which are felt to diminish the degree of cardiac mechano-receptor activation or by acting elsewhere to oppose the high levels of circulating epinephrine (Raviele, Themistoclakis & Gasparini, 1996, p. 114). However, studies of the efficacy of beta blockers in treating NCS have had mixed results. One study showed that propranolol, nadolol and placebo were all equally effective in treating vasovagal syncope (Flevari, Livanis, Theodorakis, Zarvalis, Mesiskli & Kremastinos, 2002). The physicians conducting this study concluded that beta blockers are no better than placebo at reducing neurocardiogenic syncope. Another study showed nonselective beta blockers to be more effective than beta-1-selective blockers in preventing tilt-induced syncope (Dendi & Goldstein, 2002). Calcium Channel Blockers may be effective in some patients with NCS. However, in a study comparing verapamil (a calcium channel blocker) to metoprolol (a beta blocker), verapamil was found to be less effective in the management of neurocardiogenic syncope (Jhamb, Singh, Sharda, Kaul, Goel, Talwar & Wasir, 1996). Disopyramide has negative inotropic and anticholinergic effects that may be potentially beneficial in preventing vasovagal syncope by decreasing ventricular contractibility and counteracting parasympathetic activity (Raviele, Themistoclakis & Gasparini, 1996, p. 114). Fludrocortisone is sometimes used to prevent neurocardiogenic syncope. There is considerable clinical experience and a consensus suggesting that fludrocortisone is effective (Bloomfield, 2002). Pacemakers are a somewhat controversial treatment for neurocardiogenic syncope. Many studies have suggested the efficacy of pacemakers. However, a double-blind randomized trial showed that pacing therapy did not reduce the risk of recurrent syncope in patients with vasovagal syncope. The authors of this study concluded that pacemaker therapy should not be recommended as a first-line therapy for patients with recurrent vasovagal syncope (Connolly, Sheldon, Thorpe, Roberts, Ellenbogen, Wilkoff & Morillo, 2003). Scopolamine may be effective in reducing the high vagal tone that occurs during syncopal episodes (Raviele, Themistoclakis & Gasparini, 1996, p. 115). Serotonin Reuptake Inhibitors may prevent NCS by reducing the sympathetic impulses that signal the heart to contract more strongly (Grubb & McMann, 2001, p. 115). Theophylline is an adenosine receptor blocker. It may prevent NCS, although patients sometimes discontinue theophylline because of adverse reactions (Nelson, Stanley, Love, Coyne & Schaal, 1991). Theophylline is not generally used as a first line treatment for NCS. Patients sometimes need a combination of medications to prevent recurrent neurocardiogenic syncope. To read more on NCS, please visit our neurocardiogenic syncope links page. References 1. Abe, H., Kondo, S., Kohshi, K., Nakashima, Y. (2002). Usefulness of orthostatic self-training for the prevention of neurocardiogenic syncope. Pacing & Clinical Electrophysiology, 25(10), 1454-1458. Pubmed 2. Alboni, P., Brignole, M., Menozzi, C., Raviele, A., Del Rosso, A., Dinelli, M., Solano, A., & Bottoni N. (2001). Diagnostic value of history in patients with syncope with or without heart disease. Journal of the American College of Cardiology, 37, 1921-1928. PubMed 3. Bloomfield, D. M. (2002). Strategy for the management of vasovagal syncope. Drugs & Aging, 19(3), 179-202. 4. Brignole, M., Croci, F., Menozzi, C., Solano, A., Donateo, P., Oddone, D., Puggioni, E. & Lolli, G. (2002). Isometric arm counter-pressure maneuvers to abort impending vasovagal syncope. Journal of the American College of Cardiology, 40(11), 2053-2059. PubMed 5. Brunner, L. S. & Suddarth, D. S. (2000). Assessment of cardiovascular function. In S. C. Smeltzer & B. G. Bare (Eds.), Brunner and Suddarth's textbook medical-surgical nursing (pp. 532-563). Philadelphia, PA: Lippincott Williams and Wilkins. 6. Connolly, S. J., Sheldon, R., Thorpe, K. E., Roberts, R. S., Ellenbogen, K. A., Wilkoff, B. L., Morillo, C., & Gent, M. (2003). Pacemaker therapy for prevention of syncope in patients with recurrent severe vasovagal syncope: Second Vasovagal Pacemaker Study (VPS II): a randomized trial. Journal of the American Medical Association, 289(17), 2224-2229. PubMed 7. Deering, A. (2003). Cheltenham Syncope Clinic. Retrieved May 15, 2003. http://www.syncope.co.uk/ 8. Dendi, R., & Goldstein, D. S. (2002). Meta-analysis of nonselective versus beta-1 adrenoceptor- selective blockade in prevention of tilt-induced neurocardiogenic syncope. American Journal of Cardiology, 89(11), 1319-1321. PubMed 9. Ellenbogen, K. A., Morillo, C. A., Wood, M. A., Gilligan, D. M., Eckberg, D. L., Smith, M. L. (1997). Neural monitoring of vasovagal syncope. Pacing & Clinical Electrophysiology. 20(3 Pt 2), 788-794. PubMed 10. Flevari, P., Livanis, E. G., Theodorakis, G. N., Zarvalis, E., Mesiskli, T., Kremastinos, D. T. (2002). Vasovagal syncope: a prospective, randomized, crossover evaluation of the effect of propranolol, nadolol and placebo on syncope recurrence and patients' well-being. Journal of the American College of Cardiology, 40(3), 499-504. PubMed 11. Grubb, B. P., Gerard, G., Roush, K. (1991 ). Differentiation of convulsive syncope and epilepsy with head up tilt table testing. Annals of Internal Medicine, 117, 871-876. PubMed 12. Grubb, B. P. & McMann, M. C. (2001). The fainting phenomenon: Understanding why people faint and what can be done about it. New York: Futura Publishing Company, Inc. 13. Jauregui-Renaud, K., Marquez, M. F., Hermosillo, A. G., Sobrino, A., Lara, J. L., Kostine, A., Cardenas, M. (2003). Paced breathing can prevent vasovagal syncope during head-up tilt testing. Journal Canadien de Cardiologie, 19(6), 698-700. PubMed 14. Jhamb, D. K., Singh, B., Sharda, B., Kaul, U., Goel, P., Talwar, K. K., Wasir, H. S. (1996). Comparative study of the efficacy of metoprolol and verapamil in patients with syncope and positive head-up tilt test response. American Heart Journal, 132(3), 608-611. PubMed 15. Kaufmann, H., Saadia, D., Voustianiouk, A. (2002). Midodrine in neurally mediated syncope: a double-blind, randomized, crossover study. Annals of Neurology, 52(3), 342-345. PubMed 16. Krediet, C. T., van Dijk, N., Linzer, M., van Lieshout, J. J., Wieling, W. (2002). Management of vasovagal syncope: controlling or aborting faints by leg crossing and muscle tensing. Circulation, 106(13), 1684-1689. PubMed 17. Krediet, C. T., Jardine, D. L., Cortelli, P., Visman, A. G., Wieling, W. (2004). Vasovagal syncope interrupting sleep? Heart, 90(5), e25. PubMed 18. Levine, M. M. (1999). Neurally mediated syncope in children: results of tilt testing, treatment, and long-term follow-up. Pediatric Cardiology, 20(5), 331-335. PubMed 19. Mathias, C. J. (2003). Autonomic diseases: management. Journal of Neurology, Neurosurgery & Psychiatry. 74 Suppl 3:iii, 42-47. Full Text: http://jnnp.bmjjournals.com/cgi/content/full/74/suppl_3/iii42 20. Mitro, P., Hijova E. & Mudrakova K. (2006). Role of the peripheral serotoninergic system in the pathogenesis of vasovagal syncope. Bratisl Lek Listy. 107(6-7), 248-52. PubMed 21. Nelson, S. D., Stanley, M., Love, C. J., Coyne, K. S., Schaal, S.F. (1991). The autonomic and hemodynamic effects of oral theophylline in patients with vasodepressor syncope.Archives of Internal Medicine, 151(12), :2425-2429. PubMed 22. North American Society of Pacing and Electrophysiology. (1999). Other tests: tilt table test. Retrieved June 17, 2003, from NASPE Heart Rhythm Society. No longer available. 23. On, Y. K., Park, J., Huh, J., & Kim, J. S. (2007). Is home orthostatic self-training effective in preventing neurally mediated syncope? Pacing Clin Electrophysiol. 30(5), 638-643. PubMed 24. Pachon M. J. C., Pachon, M. E. I., Pachon, M. J. C., Lobo, T. J., Pachon, M. Z., Vargas, R. N. & Jatene, A. D. (2005). "Cardioneuroablation" - new treatment for neurocardiogenic syncope, functional AV block and sinus dysfunction using catheter RF-ablation. Europace. 7(1), 1-13. PubMed 25. Qingyou, Z., Junbao, D. & Chaoshu, T. (2006). The efficacy of midodrine hydrochloride in the treatment of children with vasovagal syncope. J Pediatr, 149(6), 777-780. PubMed 26. Raviele, A., Themistoclakis, S. & Gasparini, G. (1996). Drug treatment of vasovagal syncope. In J. J. Blanc and D. Benditt (Eds.), Neurally mediated syncope: pathophysiology, investigations, and treatment (pp. 113-117). Armonk, NY: Futura Publishing Co. 27. Reybrouck, T., Heidbuchel, H., Van De Werf, F., Ector, H. (2002). Long-term follow-up results of tilt training therapy in patients with recurrent neurocardiogenic syncope. Pacing & Clinical Electrophysiology, 25(10), 1441-1446. PubMed 28. Ruiz, G. A., Calvar, C., Hermes, R., Rivadeneira, D., Bengolea, V., Chirife, R., Tentori, M. C., & Gelpi, R. J. (2003). Insulin sensitivity in young women with vasovagal syncope. American Heart Journal, 145(5), 834-840. PubMed 29. Shah, J. S., Gupta, A. K. & Lokhandwala, Y. Y. (2003). Neurally mediated syncope: an overview and approach. Journal of the Association of Physicians of India. 51, 805-810. 30. Shneerson, J. M. (2000). Handbook of sleep medicine. Oxford: Blackwell Science. 31. van Dijk, N., Quartieri, F., Blanc, J. J., Garcia-Civera, R., Brignole, M., Moya, A. & Wieling, W. (2006). Effectiveness of physical counterpressure maneuvers in preventing vasovagal syncope: the Physical Counterpressure Manoeuvres Trial (PC-Trial). J Am Coll Cardiol. 48(8), 1652-1657. 32. Zeng, C., Zhu, Z., Liu, G., Hu, W., Wang, X., Yang, C., Wang, H., He, D., & Tan, J. (1998). Randomized, double-blind, placebo-controlled trial of oral enalapril in patients with neurally mediated syncope. American Heart Jounal, 136(5), 852-858. PubMed 33. Zeng, H., Ge, K., Zhang, W., Wang, G., & Guo, L. (2008) The effect of orthostatic training in the prevention of vasovagal syncope and its influencing factors. Int Heart J. 49(6), 707-712.

What is Neurocardiogenic Syncope? Neurocardiogenic syncope is a temporary loss of consciousness associated with a drop in arterial blood pressure, quickly followed by a slowed heart rate (Grubb & McMann, 2001, p. 133). Neurocardiogenic syncope (NCS) is also referred to as vasovagal syncope or neurally mediated syncope. The terms are used interchangeably throughout this web page. What are the symptoms of NCS? Neurocardiogenic fainting usually occurs while standing. Emotional stress, stressful condition and pain may trigger an episode, especially among the young (Shah, Gupta & Lokhandwala, 2003). The onset may be abrupt or associated with warning symptoms such as fatigue, weakness, nausea, sweating, pallor, visual disturbances, abdominal discomfort, headache, pins-and-needles, lightheadedness or vertigo (Deering, 2003). Presyncopal patients may also complain of palpitations, vomiting, disorientation, and difficulty speaking clearly or coherently (Grubb & McMann, 2001, p. 60.). Other symptoms that may present before a faint include feeling either warm or cold, tremors, yawning and having a bluish/purple or red coloring to the skin (Alboni, Brignole, Menozzi, Raviele, Del Rosso, Dinelli, Solano & Bottoni, 2001). During the faint "seizure-like" activity may occur (Grubb, Gerard & Roush, 1991). This convulsive activity is thought to be distinct from a seizure disorder. Patients are sometimes symptomatic after a faint as well. Patients may complain of symptoms including nausea, clamminess, lightheadedness, headache and malaise (Deering, 2003). Patients may also experience vomiting, abdominal discomfort, weakness, tremors, cold or warm feelings and confusion (Alboni et al., 2001). Patients who experience frequent neurocardiogenic syncope may report symptoms between faints as well, such as chronic fatigue, headache, chest pain, exercise intolerance, heart "flip flops" and an inability to tolerate prolonged standing. Mechanisms and Causes of NCS When a person stands up, the pull of gravity causes blood to pool in the lower extremities. This can result in a lack of blood supply to the upper body, including the heart and brain. Normally, the body automatically adjusts to the lack of blood supply by increasing vascular tone, heart rate and cardiac output. Blood vessels contract, heart rate increases, systolic blood pressure remains about the same or drops slightly while diastolic pressure rises slightly (Brunner & Suddarth, 2000, p. 546). In those with neurocardiogenic syncope this compensatory mechanism does not always work correctly. The exact mechanisms of NCS are not completely understood, and several theories have been proposed. Many physicians hold a general consensus as to what is happening during NCS as follows: The strong contractions of the ventricle walls are thought to cause a response in the mechanoreceptors, which misinterpret what is happening and send a message to the brain that the blood pressure is actually high. In response, the sympathetic portion of the cardiovascular center reduces its impulses to the heart and blood vessels while the parasympathetic division increases its impulses (Grubb & McMann, 2001, p. 61-62). This abnormal nervous system reflex causes the heart to slow and the blood vessels to dilate (open up), further lowering blood pressure (North American Society of Pacing and Electrophysiology, 1999). Because of this faulty adjustment, NCS patients may experience intermittent fainting. A 2004 research publication suggests patients may awaken from sleep with symptoms of forthcoming neurocardiogenic syncope (Krediet, Jardine, Cortelli, Visman & Wieling, 2004). This suggestion may seem to contradict current teachings on this disorder. However, research shows that transient autonomic mechanisms that predispose to vasovagal syncope may occur during sleep (Shneerson, 2000, p. 1-15). Findings from a 2008 neurocardiogenic syncope study seem to contradict current beliefs regarding what happens during a fainting episode as well. The results did not show an increase in ventricular contractility before tilt-induced syncope, or in presence of a valuable increase of sympathetic activity. Instead, the researchers observed a reduction of atrial contractility, which they believe may be a contributory component in the pathogenesis of vasovagal syncope . There are several other factors that may be contributory components in the pathogenesis of vasovagal syncope as well. Differential changes in plasma levels of epinephrine, renin, endothelin, vasopressin, cortisol, prolactin, beta endorphins and substance P have been reported by some investigators either prior to or during a syncopal episode in patients with vasovagal syncope (Ellenbogen, Morillo, Wood, Gilligan, Eckberg & Smith, 1997). Further research has shown that galanin may play a role in one's ability to adapt to orthostatic stress. Patients may have a genetic susceptibility to NCS as well. Some researchers have suspected that serotonin might be involved in the pathogenesis of NCS. Studies in animals have shown that the withdrawal of sympathetic impulses correlates with a higher level of serotonin being present in the central nervous system, the brain and the spinal cord (Grubb & McMann, 2001, p. 57). However a later study of NCS patients found no differences in serotonin activity at the time of fainting, but did show a lower serotonin level in patients during the early phase of tilt table testing (Mitro, Hijova & Mudrakova, 2006). Another study showed that young women who had vasovagal syncope with a positive tilt test result had a greater sensitivity to insulin. Insulin, in addition to its known metabolic effects, has sympatho-excitatory and vasodilatory actions on muscular blood vessels. The authors of this study conclude that insulin hypersensitivity could be one of the predisposing factors for vasovagal episodes (Ruiz, Calvar, Hermes, Rivadeneira, Bengolea, Chirife, Tentori & Gelpi, 2003). How is NCS diagnosed? Tilt table testing is often used to diagnose NCS. However, tilt table testing can have false-negative and false-positive results (Levine, 1999). How is NCS treated? There are a variety of non-pharmacutical methods used to control and prevent neurocardiogenic syncope. No single therapy has been found to be effective in all patients. Non-pharmacutical therapies used to treat NCS include the following: Cardioneuroablationreportedly has helped some neurocardiogenic syncope patients, although the study reporting this was small and patients had only been followed up for 9 months at the time of publishing (Pachon, Pachon, Pachon, Lobo, Pachon, Vargas & Jatene, 2005). Further investigation is warranted. Counter-maneuvers may help some patients with neurocardiogenic syncope. Research has shown that physical counterpressure maneuvers are a risk-free, effective, and low-cost treatment for patients with vasovagal syncope and recognizable prodromal symptoms, and should be advised as first-line treatment in these patients (van Dijk, Quartieri, Blanc, Garcia-Civera, Brignole, Moya & Wieling, 2006). Isometric arm counter-pressure maneuvers can increase systolic blood pressure and prevent fainting in some patients with NCS (Brignole, Croci, Menozzi, Solano, Donateo, Oddone, Puggioni & Lolli, 2002). Patients can perform isometric arm counter-pressure maneuvers by gripping one had with the other and pushing both arms away from their chest. Leg crossing combined with muscle tensing at the onset of prodromal symptoms can postpone, and in some instances prevent, vasovagal syncope (Krediet, van Dijk, Linzer, van Lieshout & Wieling, 2002). Sitting with the head between the knees often is an effective means of preventing syncope (Mathias, 2003). One patient has reported success in warding off a fainting episode by gently but briskly stepping in place for a short time, bringing the knees a little upward and puffing out the exhale with each rep. Pumping the arms and fists during this counter-maneuver has helped her as well. Increasing dietary salt and fluid intake may help prevent symptoms associated with neurocardiogenic syncope (Bloomfield, 2002). Orthostatic self-training and tilt training may help select patients with NCS (Abe, Kondo, Kohshi, Nakashima, 2002). It is of greatest benefit to younger patients and those who faint frequently (Zeng, Ge, Zhang, Wang, & Guo, 2008). Orthostatic self-training involves standing against a wall, without moving, twice a day for a planned duration of up to 30 minutes. The results of orthostatic self-training studies have been mixed, with one study concluding it ineffective in reducing the positive response rate of head-up tilt test in patients with recurrent neurally mediated syncope (On, Park, Huh, & Kim, 2007). Tilt training involves inclining patients on a tilt table each day. Some patients have to continually be inclined for this therapy to be effective. This therapy will not be effective in all patients. However, one study showed that in 19 patients who abandoned tilt training after about 1 year, none of them reported fainting during daily life. The authors of this study hypothesize that the disturbed autonomic reflex activity may have been restored in these patients (Reybrouck, Heidbuchel, Van De Werf & Ector, 2002). Paced breathing may help to prevent vasovagal syncope induced by head-up tilt test. Researchers who studied the effects of paced breathing believe respiratory training could be useful in the prevention of vasovagal syncope (Jauregui-Renaud, Marquez, Hermosillo, Sobrino, Lara, Kostine & Cardenas, 2003). Removal or avoidance of agents that predispose to hypotension or dehydration can lessen the occurance of neurocardiogenic syncope (Bloomfield, 2002). Situations that can predispose an individual to syncope are listed on the POTS Place "What to Avoid" page. There are a variety of medications and medical treatments that may help prevent neurocardiogenic syncope as well. These include the following: ACE inhibitors may prevent NCS, presumably through inhibition of sympathetic system activation and the peripheral hypotensive effect (Zeng, Zhu, Liu, Hu, Wang, Yang, Wang, He & Tan, 1998). Alpha-agonists increase venous tone and decrease pooling, which may prevent activation of mechano-receptors. They also counteract the arteriolar vasodilation produced by the triggering of the vasovagal reflex (Raviele, Themistoclakis & Gasparini, 1996, p. 115). Midodrine is an example of an alpha-agonist that is used to treat NCS. Midodrine has been shown to significantly improve orthostatic tolerance during head-up tilt in patients with recurrent neurally mediated syncope (Kaufmann, Saadia & Voustianiouk, 2002). Researchers have also found Midodrine to be effective in both treating and preventing vasovagal syncope in children (Qingyou, Z., Junbao, D. & Chaoshu, T., 2006). Beta blockers have been reported in many studies to be effective in treating neurocardiogenic syncope. Presumably, these agents exert their effects through their negative inotropic actions, which are felt to diminish the degree of cardiac mechano-receptor activation or by acting elsewhere to oppose the high levels of circulating epinephrine (Raviele, Themistoclakis & Gasparini, 1996, p. 114). However, studies of the efficacy of beta blockers in treating NCS have had mixed results. One study showed that propranolol, nadolol and placebo were all equally effective in treating vasovagal syncope (Flevari, Livanis, Theodorakis, Zarvalis, Mesiskli & Kremastinos, 2002). The physicians conducting this study concluded that beta blockers are no better than placebo at reducing neurocardiogenic syncope. Another study showed nonselective beta blockers to be more effective than beta-1-selective blockers in preventing tilt-induced syncope (Dendi & Goldstein, 2002). Calcium Channel Blockers may be effective in some patients with NCS. However, in a study comparing verapamil (a calcium channel blocker) to metoprolol (a beta blocker), verapamil was found to be less effective in the management of neurocardiogenic syncope (Jhamb, Singh, Sharda, Kaul, Goel, Talwar & Wasir, 1996). Disopyramide has negative inotropic and anticholinergic effects that may be potentially beneficial in preventing vasovagal syncope by decreasing ventricular contractibility and counteracting parasympathetic activity (Raviele, Themistoclakis & Gasparini, 1996, p. 114). Fludrocortisone is sometimes used to prevent neurocardiogenic syncope. There is considerable clinical experience and a consensus suggesting that fludrocortisone is effective (Bloomfield, 2002). Pacemakers are a somewhat controversial treatment for neurocardiogenic syncope. Many studies have suggested the efficacy of pacemakers. However, a double-blind randomized trial showed that pacing therapy did not reduce the risk of recurrent syncope in patients with vasovagal syncope. The authors of this study concluded that pacemaker therapy should not be recommended as a first-line therapy for patients with recurrent vasovagal syncope (Connolly, Sheldon, Thorpe, Roberts, Ellenbogen, Wilkoff & Morillo, 2003). Scopolamine may be effective in reducing the high vagal tone that occurs during syncopal episodes (Raviele, Themistoclakis & Gasparini, 1996, p. 115). Serotonin Reuptake Inhibitors may prevent NCS by reducing the sympathetic impulses that signal the heart to contract more strongly (Grubb & McMann, 2001, p. 115). Theophylline is an adenosine receptor blocker. It may prevent NCS, although patients sometimes discontinue theophylline because of adverse reactions (Nelson, Stanley, Love, Coyne & Schaal, 1991). Theophylline is not generally used as a first line treatment for NCS. Patients sometimes need a combination of medications to prevent recurrent neurocardiogenic syncope. To read more on NCS, please visit our neurocardiogenic syncope links page. References 1. Abe, H., Kondo, S., Kohshi, K., Nakashima, Y. (2002). Usefulness of orthostatic self-training for the prevention of neurocardiogenic syncope. Pacing & Clinical Electrophysiology, 25(10), 1454-1458. Pubmed 2. Alboni, P., Brignole, M., Menozzi, C., Raviele, A., Del Rosso, A., Dinelli, M., Solano, A., & Bottoni N. (2001). Diagnostic value of history in patients with syncope with or without heart disease. Journal of the American College of Cardiology, 37, 1921-1928. PubMed 3. Bloomfield, D. M. (2002). Strategy for the management of vasovagal syncope. Drugs & Aging, 19(3), 179-202. 4. Brignole, M., Croci, F., Menozzi, C., Solano, A., Donateo, P., Oddone, D., Puggioni, E. & Lolli, G. (2002). Isometric arm counter-pressure maneuvers to abort impending vasovagal syncope. Journal of the American College of Cardiology, 40(11), 2053-2059. PubMed 5. Brunner, L. S. & Suddarth, D. S. (2000). Assessment of cardiovascular function. In S. C. Smeltzer & B. G. Bare (Eds.), Brunner and Suddarth's textbook medical-surgical nursing (pp. 532-563). Philadelphia, PA: Lippincott Williams and Wilkins. 6. Connolly, S. J., Sheldon, R., Thorpe, K. E., Roberts, R. S., Ellenbogen, K. A., Wilkoff, B. L., Morillo, C., & Gent, M. (2003). Pacemaker therapy for prevention of syncope in patients with recurrent severe vasovagal syncope: Second Vasovagal Pacemaker Study (VPS II): a randomized trial. Journal of the American Medical Association, 289(17), 2224-2229. PubMed 7. Deering, A. (2003). Cheltenham Syncope Clinic. Retrieved May 15, 2003. http://www.syncope.co.uk/ 8. Dendi, R., & Goldstein, D. S. (2002). Meta-analysis of nonselective versus beta-1 adrenoceptor- selective blockade in prevention of tilt-induced neurocardiogenic syncope. American Journal of Cardiology, 89(11), 1319-1321. PubMed 9. Ellenbogen, K. A., Morillo, C. A., Wood, M. A., Gilligan, D. M., Eckberg, D. L., Smith, M. L. (1997). Neural monitoring of vasovagal syncope. Pacing & Clinical Electrophysiology. 20(3 Pt 2), 788-794. PubMed 10. Flevari, P., Livanis, E. G., Theodorakis, G. N., Zarvalis, E., Mesiskli, T., Kremastinos, D. T. (2002). Vasovagal syncope: a prospective, randomized, crossover evaluation of the effect of propranolol, nadolol and placebo on syncope recurrence and patients' well-being. Journal of the American College of Cardiology, 40(3), 499-504. PubMed 11. Grubb, B. P., Gerard, G., Roush, K. (1991 ). Differentiation of convulsive syncope and epilepsy with head up tilt table testing. Annals of Internal Medicine, 117, 871-876. PubMed 12. Grubb, B. P. & McMann, M. C. (2001). The fainting phenomenon: Understanding why people faint and what can be done about it. New York: Futura Publishing Company, Inc. 13. Jauregui-Renaud, K., Marquez, M. F., Hermosillo, A. G., Sobrino, A., Lara, J. L., Kostine, A., Cardenas, M. (2003). Paced breathing can prevent vasovagal syncope during head-up tilt testing. Journal Canadien de Cardiologie, 19(6), 698-700. PubMed 14. Jhamb, D. K., Singh, B., Sharda, B., Kaul, U., Goel, P., Talwar, K. K., Wasir, H. S. (1996). Comparative study of the efficacy of metoprolol and verapamil in patients with syncope and positive head-up tilt test response. American Heart Journal, 132(3), 608-611. PubMed 15. Kaufmann, H., Saadia, D., Voustianiouk, A. (2002). Midodrine in neurally mediated syncope: a double-blind, randomized, crossover study. Annals of Neurology, 52(3), 342-345. PubMed 16. Krediet, C. T., van Dijk, N., Linzer, M., van Lieshout, J. J., Wieling, W. (2002). Management of vasovagal syncope: controlling or aborting faints by leg crossing and muscle tensing. Circulation, 106(13), 1684-1689. PubMed 17. Krediet, C. T., Jardine, D. L., Cortelli, P., Visman, A. G., Wieling, W. (2004). Vasovagal syncope interrupting sleep? Heart, 90(5), e25. PubMed 18. Levine, M. M. (1999). Neurally mediated syncope in children: results of tilt testing, treatment, and long-term follow-up. Pediatric Cardiology, 20(5), 331-335. PubMed 19. Mathias, C. J. (2003). Autonomic diseases: management. Journal of Neurology, Neurosurgery & Psychiatry. 74 Suppl 3:iii, 42-47. Full Text: http://jnnp.bmjjournals.com/cgi/content/full/74/suppl_3/iii42 20. Mitro, P., Hijova E. & Mudrakova K. (2006). Role of the peripheral serotoninergic system in the pathogenesis of vasovagal syncope. Bratisl Lek Listy. 107(6-7), 248-52. PubMed 21. Nelson, S. D., Stanley, M., Love, C. J., Coyne, K. S., Schaal, S.F. (1991). The autonomic and hemodynamic effects of oral theophylline in patients with vasodepressor syncope.Archives of Internal Medicine, 151(12), :2425-2429. PubMed 22. North American Society of Pacing and Electrophysiology. (1999). Other tests: tilt table test. 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Reybrouck, T., Heidbuchel, H., Van De Werf, F., Ector, H. (2002). Long-term follow-up results of tilt training therapy in patients with recurrent neurocardiogenic syncope. Pacing & Clinical Electrophysiology, 25(10), 1441-1446. PubMed 28. Ruiz, G. A., Calvar, C., Hermes, R., Rivadeneira, D., Bengolea, V., Chirife, R., Tentori, M. C., & Gelpi, R. J. (2003). Insulin sensitivity in young women with vasovagal syncope. American Heart Journal, 145(5), 834-840. PubMed 29. Shah, J. S., Gupta, A. K. & Lokhandwala, Y. Y. (2003). Neurally mediated syncope: an overview and approach. Journal of the Association of Physicians of India. 51, 805-810. 30. Shneerson, J. M. (2000). Handbook of sleep medicine. Oxford: Blackwell Science. 31. van Dijk, N., Quartieri, F., Blanc, J. J., Garcia-Civera, R., Brignole, M., Moya, A. & Wieling, W. (2006). Effectiveness of physical counterpressure maneuvers in preventing vasovagal syncope: the Physical Counterpressure Manoeuvres Trial (PC-Trial). 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The following are selected articles relating to POTS. These articles can be obtained at medical libraries or ordered online at Loansome Doc Ordering System. Postural Orthostatic Tachycardia in a Patient with Type 2 Diabetes with Diabetic Neuropathy Tomichi Y, Kawano H, Mukaino A, Chiba Ak Doi Y, Arakawa S, Ishimatsu T, Fukae S, Abiru N, Maemura K 2018 Oct PubMed Quantitative assessment of autonomic symptom burden in Postural tachycardia syndrome (POTS) Rea NA, Campbell CL, Cortez MM 2017 June PubMed Painful temporomandibular disorders are common in patients with POTS and impact significantly upon quality of life. Durham J, McDonald C. Hutchinson L, Newton JL 2015 PubMed Neurocardiogenic syncope coexisting with postural orthostatic tachycardia syndrome in patients suffering from orthostatic intolerance: a combined form of autonomic dysfunction. Kanjwal K, Sheikh M, Karabin B, Kanjwal Y, Grubb BP 2011 May PubMed Comorbidities in Pediatric Patients with Postural Orthostatic Tachycardia Syndrome. Ojha A, Chelimsky TC, Chelimsky G. J Pediatr. 2010 Aug 17. PubMed New onset postural orthostatic tachycardia syndrome following ablation of AV node reentrant tachycardia. Kanjwal K, Karabin B, Sheikh M, Kanjwal Y, Grubb BP. J Interv Card Electrophysiol. 2010 Aug 14. PubMed Flow-mediated vasodilation and endothelium function in children with postural orthostatic tachycardia syndrome. Liao Y, Chen S, Liu X, Zhang Q, Ai Y, Wang Y, Jin H, Tang C, Du J. Am J Cardiol. 2010 Aug 1;106(3):378-82. PubMed Effect of pregnancy on postural tachycardia syndrome. Kimpinski K, Iodice V, Sandroni P, Low PA. Mayo Clin Proc. 2010 Jul;85(7):639-44. Epub 2010 Jun 1. PubMed Orthostatic intolerance and the headache patient. Mack KJ, Johnson JN, Rowe PC. Semin Pediatr Neurol. 2010 Jun;17(2):109-16. PubMed Use of Octreotide in the Treatment of Refractory Orthostatic Intolerance. Kanjwal K, Saeed B, Karabin B, Kanjwal Y, Grubb BP. Am J Ther. 2010 Jun 9. PubMed Menstrual Cycle Affects Renal-Adrenal and Hemodynamic Responses During Prolonged Standing in the Postural Orthostatic Tachycardia Syndrome. Fu Q, Vangundy TB, Shibata S, Auchus RJ, Williams GH, Levine BD. Hypertension. 2010 May 17. PubMed Use of Methylphenidate in the Treatment of Patients Suffering From Refractory Postural Tachycardia Syndrome. Kanjwal K, Saeed B, Karabin B, Kanjwal Y, Grubb BP. Am J Ther. 2010 May 10. PubMed Acute fluid ingestion in the treatment of orthostatic intolerance - important implications for daily practice. Z'graggen WJ, Hess CW, Humm AM. Eur J Neurol. 2010 Apr 20. PubMed Comparative clinical profile of postural orthostatic tachycardia patients with and without joint hypermobility syndrome. Kanjwal K, Saeed B, Karabin B, Kanjwal Y, Grubb BP. Indian Pacing Electrophysiol J. 2010 Apr 1;10(4):173-8. PubMed Autonomic dysfunction presenting as postural orthostatic tachycardia syndrome in patients with multiple sclerosis. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Int J Med Sci. 2010 Mar 11;7:62-7. PubMed Orthostatic syndromes differ in syncope frequency. Ojha A, McNeeley K, Heller E, Alshekhlee A, Chelimsky G, Chelimsky TC. Am J Med. 2010 Mar;123(3):245-9. PubMed Efficiency evaluation of autonomic heart control by using the principal component analysis of ECG P-wave. Krisciukaitis A, Simoliuniene R, Tamosiunas M, Saferis V, Vainoras A, Gargasas L. Methods Inf Med. 2010 Mar 16;49(2):161-7. Epub 2010 Feb 22. PubMed Postural orthostatic tachycardia syndrome: a clinical review. Johnson JN, Mack KJ, Kuntz NL, Brands CK, Porter CJ, Fischer PR. Pediatr Neurol. 2010 Feb;42(2):77-85. PubMed Perioperative care of an adolescent with postural orthostatic tachycardia syndrome. Kernan S, Tobias JD. Saudi J Anaesth. 2010 Jan;4(1):23-7. Full text Distal sudomotor findings in postural tachycardia syndrome. Peltier AC, Garland E, Raj SR, Sato K, Black B, Song Y, Wang L, Biaggioni I, Diedrich A, Robertson D. Clin Auton Res. 2009 Dec 25. PubMed Postural Orthostatic Tachycardia Syndrome: A Rare Complication Following Electrical Injury. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Pacing Clin Electrophysiol. 2009 Dec 10. PubMed Postpartum postural orthostatic tachycardia syndrome in a patient with the joint hypermobility syndrome. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Cardiol Res Pract. 2009;2009:187543. Epub 2009 Oct 11. Full Text Cardiac Neurotransmission Imaging with 123I-Meta-iodobenzylguanidine in Postural Tachycardia Syndrome. Haensch CA, Lerch H, Schlemmer H, Jigalin A, Isenmann S. J Neurol Neurosurg Psychiatry. 2009 Aug 16. PubMed Outcomes of pregnancy in patients with preexisting postural tachycardia syndrome. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Pacing Clin Electrophysiol. 2009 Aug;32(8):1000-3. PubMed Propranolol Decreases Tachycardia and Improves Symptoms in the Postural Tachycardia Syndrome. Less Is More. Raj SR, Black BK, Biaggioni I, Paranjape SY, Ramirez M, Dupont WD, Robertson D. Circulation. 2009 Aug 17. PubMed Decreased Upright Cerebral Blood Flow and Cerebral Autoregulation in Normocapnic Postural Tachycardia Syndrome. Ocon AJ, Medow MS, Taneja I, Clark D, Stewart JM. Am J Physiol Heart Circ Physiol. 2009 Jun 5. PubMed Autonomic Testing in Functional Gastrointestinal Disorders: Implications of Reproducible Gastrointestinal Complaints during Tilt Table Testing. Safder S, Chelimsky TC, O'Riordan MA, Chelimsky G. Gastroenterol Res Pract. 2009;2009:868496. Epub 2009 May 5. Full Text Defects in cutaneous angiotensin-converting enzyme 2 and angiotensin-(1-7) production in postural tachycardia syndrome. Stewart JM, Ocon AJ, Clarke D, Taneja I, Medow MS. Hypertension. 2009 May;53(5):767-74. Full Text What is the optimal duration of tilt testing for the assessment of patients with suspected postural tachycardia syndrome? Carew S, Cooke J, O'Connor M, Donnelly T, Costelloe A, Sheehy C, Lyons D. Europace. 2009 May;11(5):635-7. Epub 2009 Mar 4. PubMed Quantitative study on cerebral blood volume determined by a near-infrared spectroscopy during postural change in children. Kim YT, Tanaka H, Takaya R, Kajiura M, Tamai H, Arita M. Acta Paediatr. 2009 Mar;98(3):466-71. PubMed Antibody titers predict clinical features of autoimmune autonomic ganglionopathy. Gibbons CH, Freeman R. Auton Neurosci. 2009 Mar 12;146(1-2):8-12. PubMed Japanese clinical guidelines for juvenile orthostatic dysregulation version 1. Tanaka H, Fujita Y, Takenaka Y, Kajiwara S, Masutani S, Ishizaki Y, Matsushima R, Shiokawa H, Shiota M, Ishitani N, Kajiura M, Honda K; Task Force of Clinical Guidelines for Child Orthostatic Dysregulation, Japanese Society of Psychosomatic Pediatrics. Pediatr Int. 2009 Feb;51(1):169-79. PubMed Outcomes in adolescents with postural orthostatic tachycardia syndrome treated with midodrine and beta-blockers. Lai CC, Fischer PR, Brands CK, Fisher JL, Porter CB, Driscoll SW, Graner KK. Pacing Clin Electrophysiol. 2009 Feb;32(2):234-8. PubMed. Postural tachycardia syndrome (POTS). Low PA, Sandroni P, Joyner M, Shen WK J Cardiovasc Electrophysiol. 2009 Mar;20(3):352-8. Epub 2009 Jan 16. Review. PubMed Treatment of inappropriate sinus tachycardia with ivabradine in a patient with postural orthostatic tachycardia syndrome and a dual chamber pacemaker. Khan S, Hamid S, Rinaldi C. Pacing Clin Electrophysiol. 2009 Jan;32(1):131-3. PubMed Effect of selective alpha1 receptor agonist in the treatment of children with postural orthostatic tachycardia syndrome. Chen L, DU JB, Jin HF, Zhang QY, Li WZ, Wang L, Wang YL. Zhonghua Er Ke Za Zhi. 2008 Sep;46(9):688-91. Chinese. PubMed Postural orthostatic tachycardia in a teenager with Klinefelter syndrome. Hainstock MR, Gruchala NE, Fike N, Samson RA, Klewer SE, Barber BJ. Congenit Heart Dis. 2008 Nov-Dec;3(6):440-2. PubMed Autonomic dysfunction in fibromyalgia syndrome: postural orthostatic tachycardia. Staud R. Curr Rheumatol Rep. 2008 Dec;10(6):463-6. PubMed Postural orthostatic tachycardia syndrome is an under-recognized condition in chronic fatigue syndrome. Hoad A, Spickett G, Elliott J, Newton J. QJM. 2008 Dec;101(12):961-5. Epub 2008 Sep 19. PubMed Postural orthostatic tachycardia in a teenager with Klinefelter syndrome. Hainstock MR, Gruchala NE, Fike N, Samson RA, Klewer SE, Barber BJ. Congenit Heart Dis. 2008 Nov;3(6):440-2. PubMed Psychiatric Profile and Attention Deficits in Postural Tachycardia Syndrome. Raj V, Haman KL, Raj SR, Byrne D, Blakely RD, Biaggioni I, Robertson D, Shelton RC. J Neurol Neurosurg Psychiatry. 2008 Oct 31. PubMed Reversible postural tachycardia syndrome due to inadvertent overuse of Red Bull((R)). Terlizzi R, Rocchi C, Serra M, Solieri L, Cortelli P. Clin Auton Res. 2008 Aug;18(4):221-3. Epub 2008 Aug 5. PubMed Anesthesia for caesarean section in a patient with Ehlers-Danlos syndrome associated with postural orthostatic tachycardia syndrome. Jones TL, Ng C. Int J Obstet Anesth. 2008 Jul 8. PubMed Cardiovascular autonomic reflexes on the postural orthostatic tachycardia syndrome. Benjelloun H, Benjelloun H, Aboudrar S, Coghlan L, Benomar M. Ann Cardiol Angeiol (Paris). 2008 Jun 10. PubMed Postural tachycardia syndrome.Grubb BP. Circulation. 2008 May 27;117(21):2814-7. Full Text Invited Article: Autonomic ganglia: target and novel therapeutic tool.Vernino S, Sandroni P, Singer W, Low PA. Neurology. 2008 May 13;70(20):1926-32. PubMed Orthostatic intolerance and gastrointestinal motility in adolescents with nausea and abdominal pain. Antiel RM, Risma JM, Grothe RM, Brands CK, Fischer PR. J Pediatr Gastroenterol Nutr. 2008 Mar;46(3):285-8. PubMed Postural tachycardia syndrome and coronary artery bridge. Abdelmoneim SS, Moustafa S, Mookadam F. Europace. 2008 Apr;10(4):482-5. Epub 2008 Mar 13. PubMed A Matched Case Control Study of Orthostatic Intolerance in Children/Adolescents With Chronic Fatigue Syndrome. Galland BC, Jackson PM, Sayers RM, Taylor BJ. Pediatr Res. 2008 Feb;63(2):196-202. PubMed Angiotensin II type 1 receptor blockade corrects cutaneous nitric oxide deficit in postural tachycardia syndrome. Stewart JM, Taneja I, Glover J, Medow MS. Am J Physiol Heart Circ Physiol. 2008 Jan;294(1):H466-73. PubMed A multicenter study on treatment of autonomous nerve-mediated syncope in children with beta-receptor blocker. Chen L, DU JB, Zhang QY, Wang C, DU ZD, Wang HW, Tian H, Chen JJ, Wang YL, Hu XF, Li WZ, Han L. Zhonghua Er Ke Za Zhi. 2007 Dec;45(12):885-8. PubMed Takotsubo cardiomyopathy in a patient with postural tachycardia syndrome. Khurana RK. Clin Auton Res. 2007 Oct 19. PubMed Postural tachycardia syndrome with asystole on head-up tilt. Alshekhlee A, Guerch M, Ridha F, McNeeley K, Chelimsky TC. Clin Auton Res. 2007 Oct 19 PubMed Symptom improvement in postural orthostatic tachycardia syndrome with the sinus node blocker ivabradine. Ewan V, Norton M, Newton JL. Europace. 2007 Dec;9(12):1202. Epub 2007 Oct 19. PubMed Sympathovagal balance analysis in idiopathic postural orthostatic tachycardia syndrome. Russo V, De Crescenzo I, Ammendola E, Santangelo L, Calabrò R. Acta Biomed. 2007 Aug;78(2):133-8. PubMed Cardiac denervation in postural tachycardia syndrome.Haensch CA, Lerch H, Jigalin A, Schlemmer H, Isenmann S. Clin Auton Res. 2007 Sep 26. PubMed Postural syncope: mechanisms and management.Vaddadi G, Lambert E, Corcoran SJ, Esler MD. Med J Aust. 2007 Sep 3;187(5):299-304. PubMed Treatment of autonomic neuropathy, postural tachycardia and orthostatic syncope with octreotide LAR. Hoeldtke RD, Bryner KD, Hoeldtke ME, Hobbs G. Clin Auton Res. 2007 Aug 31. PubMed Blood volume perturbations in the postural tachycardia syndrome. Raj SR, Robertson D. Am J Med Sci. 2007 Jul;334(1):57-60. PubMed Reduced stroke volume during exercise in postural tachycardia syndrome. Masuki S, Eisenach JH, Schrage WG, Johnson CP, Dietz NM, Wilkins BW, Sandroni P, Low PA, Joyner MJ. J Appl Physiol. 2007 Jul 12; PubMed Postural orthostatic tachycardia syndrome. Agarwal AK, Garg R, Ritch A, Sarkar P. Postgrad Med J. 2007 Jul;83(981):478-80. PubMed Reduced Central Blood Volume and Cardiac Output, and Increased Vascular Resistance during Static Handgrip Exercise in Postural Tachycardia Syndrome. Stewart J, Taneja I, Medow MS. Am J Physiol Heart Circ Physiol. 2007 Jul 6; PubMed Postural orthostatic tachycardia syndrome: an underrecognized disorder.PandianJD, Dalton K, Henderson RD, McCombe PA. Intern Med J. 2007 Jul 19;37(8):529-535. PubMed Sympathetic neural activity, sex dimorphism, and postural tachycardia syndrome. Bonyhay I, Freeman R. Ann Neurol. 2007 Mar 14. PubMed Postural orthostatic tachycardia syndrome: the Mayo clinic experience. Thieben MJ, Sandroni P, Sletten DM, Benrud-Larson LM, Fealey RD, Vernino S, Lennon VA, Shen WK, Low PA. Mayo Clin Proc. 2007 Mar;82(3):308-13. Full Text The postural tachycardia syndrome. Medow MS, Stewart JM. Cardiol Rev. 2007 Mar-Apr;15(2):67-75. PubMed Pyridostigmine in the treatment of orthostatic intolerance. Gales BJ, Gales MA. Ann Pharmacother. 2007 Feb;41(2):314-8. Epub 2007 Feb 6. PubMed Postural orthostatic tachycardia syndrome: anesthetic implications in the obstetric patient.McEvoy MD, Low PA, Hebbar L. Anesth Analg. 2007 Jan;104(1):166-7. PubMed Episodic hypertension in postural orthostatic tachycardia syndrome. Carvajal Roca E, Torro Domenech I. Lurbe Ferrer E. An Pediatr (Barc). 2006 Nov;65(5):496-9. PubMed Excessive Heart Rate Response to Orthostatic Stress in Postural Tachycardia Syndrome is Not Caused by Anxiety. Masuki S, Eisenach JH, Johnson C, Dietz NM, Benrud-Larson L, Schrage WG, Curry TB, Sandroni P, Low PA, Joyner MJ. J Appl Physiol. 2006 Nov 16. PubMed Treatment of postural tachycardia syndrome: a comparison of octreotide and midodrine. Hoeldtke RD, Bryner KD, Hoeldtke ME, Hobbs G. Clin Auton Res. 2006 Oct 11 PubMed Pharmacokinetics of Pyridostigmine in a Child With Postural Tachycardia Syndrome. Filler G, Gow RM, Nadarajah R, Jacob P, Johnson G, Zhang YL, Christians U. Pediatrics. 2006 Oct 2; PubMed The Postural Tachycardia Syndrome (POTS): Pathophysiology, Diagnosis & Management. Raj SR. Indian Pacing Electrophysiol J. 2006 Apr 1;6(2):84-99. PubMed Experimental induction of panic-like symptoms in patients with postural tachycardia syndrome. Khurana RK. 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Braune S, Wrocklage C, Schulte-Monting J, Schnitzer R, Lucking CH. Clin Auton Res. 1999 Apr;9(2):97-101. PMID: 10225614 [PubMed - indexed for MEDLINE] From PubMed Cerebrovascular regulation in the postural orthostatic tachycardia syndrome (POTS). Low PA, Novak V, Spies JM, Novak P, Petty GW. Am J Med Sci. 1999 Feb;317(2):124-33. PMID: 10037116 [PubMed - indexed for MEDLINE] From PubMed Clinical and laboratory indices that enhance the diagnosis of postural tachycardia syndrome. Novak V, Novak P, Opfer-Gehrking TL, O'Brien PC, Low PA. Mayo Clin Proc. 1998 Dec;73(12):1141-50. PMID: 9868411 [PubMed - indexed for MEDLINE] From PubMed Autonomic neuropathies. Low PA. Curr Opin Neurol. 1998 Oct;11(5):531-7. PMID: 9848003 [PubMed - indexed for MEDLINE] From PubMed [Orthostatic intolerance. A review and clinical case]. Freitas J, Almeida J, Azevedo E, Carvalho MJ, Costa O, de Freitas AF. Rev Port Cardiol. 1998 Sep;17(9):715-20. Portuguese. PMID: 9834642 [PubMed - indexed for MEDLINE] From PubMed [Orthostatic postural tachycardia: study of 8 patients]. Santiago Perez S, Ferrer Gila T. Med Clin (Barc). 1998 Feb 7;110(4):138-41. Spanish. PMID: 9541904 [PubMed - indexed for MEDLINE] From PubMed The postural orthostatic tachycardia syndrome: a neurocardiogenic variant identified during head-up tilt table testing. Grubb BP, Kosinski DJ, Boehm K, Kip K. Pacing Clin Electrophysiol. 1997 Sep;20(9 Pt 1):2205-12. PMID: 9309745 [PubMed - indexed for MEDLINE] From PubMed Postural tachycardia syndrome: time frequency mapping. Novak V, Novak P, Opfer-Gehrking TL, Low PA. J Auton Nerv Syst. 1996 Dec 14;61(3):313-20. PMID: 8988490 [PubMed - indexed for MEDLINE] From PubMed Certain cardiovascular indices predict syncope in the postural tachycardia syndrome. Sandroni P, Opfer-Gehrking TL, Benarroch EE, Shen WK, Low PA. Clin Auton Res. 1996 Aug;6(4):225-31. PMID: 8902319 [PubMed - indexed for MEDLINE] From PubMed Postural tachycardia syndrome (POTS). Low PA, Opfer-Gehrking TL, Textor SC, Benarroch EE, Shen WK, Schondorf R, Suarez GA, Rummans TA. Neurology. 1995 Apr;45(4 Suppl 5):S19-25. PMID: 7746369 [PubMed - indexed for MEDLINE] From PubMed Comparison of the postural tachycardia syndrome (POTS) with orthostatic hypotension due to autonomic failure. Low PA, Opfer-Gehrking TL, Textor SC, Schondorf R, Suarez GA, Fealey RD, Camilleri M. J Auton Nerv Syst. 1994 Dec 15;50(2):181-8. PMID: 7884158 [PubMed - indexed for MEDLINE] From PubMed Autonomic neuropathies. Low PA. Curr Opin Neurol. 1994 Oct;7(5):402-6. PMID: 7804460 [PubMed - indexed for MEDLINE] From PubMed Autonomic nervous system function. Low PA. J Clin Neurophysiol. 1993 Jan;10(1):14-27. PMID: 8458992 [PubMed - indexed for MEDLINE] From PubMed Idiopathic postural orthostatic tachycardia syndrome: an attenuated form of acute pandysautonomia? Schondorf R, Low PA. Neurology. 1993 Jan;43(1):132-7. PMID: 8423877 [PubMed - indexed for MEDLINE] From PubMed

The following are selected articles relating to POTS. These articles can be obtained at medical libraries or ordered online at Loansome Doc Ordering System. Postural Orthostatic Tachycardia in a Patient with Type 2 Diabetes with Diabetic Neuropathy Tomichi Y, Kawano H, Mukaino A, Chiba Ak Doi Y, Arakawa S, Ishimatsu T, Fukae S, Abiru N, Maemura K 2018 Oct PubMed Quantitative assessment of autonomic symptom burden in Postural tachycardia syndrome (POTS) Rea NA, Campbell CL, Cortez MM 2017 June PubMed Painful temporomandibular disorders are common in patients with POTS and impact significantly upon quality of life. Durham J, McDonald C. Hutchinson L, Newton JL 2015 PubMed Neurocardiogenic syncope coexisting with postural orthostatic tachycardia syndrome in patients suffering from orthostatic intolerance: a combined form of autonomic dysfunction. Kanjwal K, Sheikh M, Karabin B, Kanjwal Y, Grubb BP 2011 May PubMed Comorbidities in Pediatric Patients with Postural Orthostatic Tachycardia Syndrome. Ojha A, Chelimsky TC, Chelimsky G. J Pediatr. 2010 Aug 17. PubMed New onset postural orthostatic tachycardia syndrome following ablation of AV node reentrant tachycardia. Kanjwal K, Karabin B, Sheikh M, Kanjwal Y, Grubb BP. J Interv Card Electrophysiol. 2010 Aug 14. PubMed Flow-mediated vasodilation and endothelium function in children with postural orthostatic tachycardia syndrome. Liao Y, Chen S, Liu X, Zhang Q, Ai Y, Wang Y, Jin H, Tang C, Du J. Am J Cardiol. 2010 Aug 1;106(3):378-82. PubMed Effect of pregnancy on postural tachycardia syndrome. Kimpinski K, Iodice V, Sandroni P, Low PA. Mayo Clin Proc. 2010 Jul;85(7):639-44. Epub 2010 Jun 1. PubMed Orthostatic intolerance and the headache patient. Mack KJ, Johnson JN, Rowe PC. Semin Pediatr Neurol. 2010 Jun;17(2):109-16. PubMed Use of Octreotide in the Treatment of Refractory Orthostatic Intolerance. Kanjwal K, Saeed B, Karabin B, Kanjwal Y, Grubb BP. Am J Ther. 2010 Jun 9. PubMed Menstrual Cycle Affects Renal-Adrenal and Hemodynamic Responses During Prolonged Standing in the Postural Orthostatic Tachycardia Syndrome. Fu Q, Vangundy TB, Shibata S, Auchus RJ, Williams GH, Levine BD. Hypertension. 2010 May 17. PubMed Use of Methylphenidate in the Treatment of Patients Suffering From Refractory Postural Tachycardia Syndrome. Kanjwal K, Saeed B, Karabin B, Kanjwal Y, Grubb BP. Am J Ther. 2010 May 10. PubMed Acute fluid ingestion in the treatment of orthostatic intolerance - important implications for daily practice. Z'graggen WJ, Hess CW, Humm AM. Eur J Neurol. 2010 Apr 20. PubMed Comparative clinical profile of postural orthostatic tachycardia patients with and without joint hypermobility syndrome. Kanjwal K, Saeed B, Karabin B, Kanjwal Y, Grubb BP. Indian Pacing Electrophysiol J. 2010 Apr 1;10(4):173-8. PubMed Autonomic dysfunction presenting as postural orthostatic tachycardia syndrome in patients with multiple sclerosis. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Int J Med Sci. 2010 Mar 11;7:62-7. PubMed Orthostatic syndromes differ in syncope frequency. Ojha A, McNeeley K, Heller E, Alshekhlee A, Chelimsky G, Chelimsky TC. Am J Med. 2010 Mar;123(3):245-9. PubMed Efficiency evaluation of autonomic heart control by using the principal component analysis of ECG P-wave. Krisciukaitis A, Simoliuniene R, Tamosiunas M, Saferis V, Vainoras A, Gargasas L. Methods Inf Med. 2010 Mar 16;49(2):161-7. Epub 2010 Feb 22. PubMed Postural orthostatic tachycardia syndrome: a clinical review. Johnson JN, Mack KJ, Kuntz NL, Brands CK, Porter CJ, Fischer PR. Pediatr Neurol. 2010 Feb;42(2):77-85. PubMed Perioperative care of an adolescent with postural orthostatic tachycardia syndrome. Kernan S, Tobias JD. Saudi J Anaesth. 2010 Jan;4(1):23-7. Full text Distal sudomotor findings in postural tachycardia syndrome. Peltier AC, Garland E, Raj SR, Sato K, Black B, Song Y, Wang L, Biaggioni I, Diedrich A, Robertson D. Clin Auton Res. 2009 Dec 25. PubMed Postural Orthostatic Tachycardia Syndrome: A Rare Complication Following Electrical Injury. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Pacing Clin Electrophysiol. 2009 Dec 10. PubMed Postpartum postural orthostatic tachycardia syndrome in a patient with the joint hypermobility syndrome. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Cardiol Res Pract. 2009;2009:187543. Epub 2009 Oct 11. Full Text Cardiac Neurotransmission Imaging with 123I-Meta-iodobenzylguanidine in Postural Tachycardia Syndrome. Haensch CA, Lerch H, Schlemmer H, Jigalin A, Isenmann S. J Neurol Neurosurg Psychiatry. 2009 Aug 16. PubMed Outcomes of pregnancy in patients with preexisting postural tachycardia syndrome. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Pacing Clin Electrophysiol. 2009 Aug;32(8):1000-3. PubMed Propranolol Decreases Tachycardia and Improves Symptoms in the Postural Tachycardia Syndrome. Less Is More. Raj SR, Black BK, Biaggioni I, Paranjape SY, Ramirez M, Dupont WD, Robertson D. Circulation. 2009 Aug 17. PubMed Decreased Upright Cerebral Blood Flow and Cerebral Autoregulation in Normocapnic Postural Tachycardia Syndrome. Ocon AJ, Medow MS, Taneja I, Clark D, Stewart JM. Am J Physiol Heart Circ Physiol. 2009 Jun 5. PubMed Autonomic Testing in Functional Gastrointestinal Disorders: Implications of Reproducible Gastrointestinal Complaints during Tilt Table Testing. Safder S, Chelimsky TC, O'Riordan MA, Chelimsky G. Gastroenterol Res Pract. 2009;2009:868496. Epub 2009 May 5. Full Text Defects in cutaneous angiotensin-converting enzyme 2 and angiotensin-(1-7) production in postural tachycardia syndrome. Stewart JM, Ocon AJ, Clarke D, Taneja I, Medow MS. Hypertension. 2009 May;53(5):767-74. Full Text What is the optimal duration of tilt testing for the assessment of patients with suspected postural tachycardia syndrome? Carew S, Cooke J, O'Connor M, Donnelly T, Costelloe A, Sheehy C, Lyons D. Europace. 2009 May;11(5):635-7. Epub 2009 Mar 4. PubMed Quantitative study on cerebral blood volume determined by a near-infrared spectroscopy during postural change in children. Kim YT, Tanaka H, Takaya R, Kajiura M, Tamai H, Arita M. Acta Paediatr. 2009 Mar;98(3):466-71. PubMed Antibody titers predict clinical features of autoimmune autonomic ganglionopathy. Gibbons CH, Freeman R. Auton Neurosci. 2009 Mar 12;146(1-2):8-12. PubMed Japanese clinical guidelines for juvenile orthostatic dysregulation version 1. Tanaka H, Fujita Y, Takenaka Y, Kajiwara S, Masutani S, Ishizaki Y, Matsushima R, Shiokawa H, Shiota M, Ishitani N, Kajiura M, Honda K; Task Force of Clinical Guidelines for Child Orthostatic Dysregulation, Japanese Society of Psychosomatic Pediatrics. Pediatr Int. 2009 Feb;51(1):169-79. PubMed Outcomes in adolescents with postural orthostatic tachycardia syndrome treated with midodrine and beta-blockers. Lai CC, Fischer PR, Brands CK, Fisher JL, Porter CB, Driscoll SW, Graner KK. Pacing Clin Electrophysiol. 2009 Feb;32(2):234-8. PubMed. Postural tachycardia syndrome (POTS). Low PA, Sandroni P, Joyner M, Shen WK J Cardiovasc Electrophysiol. 2009 Mar;20(3):352-8. Epub 2009 Jan 16. Review. PubMed Treatment of inappropriate sinus tachycardia with ivabradine in a patient with postural orthostatic tachycardia syndrome and a dual chamber pacemaker. Khan S, Hamid S, Rinaldi C. Pacing Clin Electrophysiol. 2009 Jan;32(1):131-3. PubMed Effect of selective alpha1 receptor agonist in the treatment of children with postural orthostatic tachycardia syndrome. Chen L, DU JB, Jin HF, Zhang QY, Li WZ, Wang L, Wang YL. Zhonghua Er Ke Za Zhi. 2008 Sep;46(9):688-91. Chinese. PubMed Postural orthostatic tachycardia in a teenager with Klinefelter syndrome. Hainstock MR, Gruchala NE, Fike N, Samson RA, Klewer SE, Barber BJ. Congenit Heart Dis. 2008 Nov-Dec;3(6):440-2. PubMed Autonomic dysfunction in fibromyalgia syndrome: postural orthostatic tachycardia. Staud R. Curr Rheumatol Rep. 2008 Dec;10(6):463-6. PubMed Postural orthostatic tachycardia syndrome is an under-recognized condition in chronic fatigue syndrome. Hoad A, Spickett G, Elliott J, Newton J. QJM. 2008 Dec;101(12):961-5. Epub 2008 Sep 19. PubMed Postural orthostatic tachycardia in a teenager with Klinefelter syndrome. Hainstock MR, Gruchala NE, Fike N, Samson RA, Klewer SE, Barber BJ. Congenit Heart Dis. 2008 Nov;3(6):440-2. PubMed Psychiatric Profile and Attention Deficits in Postural Tachycardia Syndrome. Raj V, Haman KL, Raj SR, Byrne D, Blakely RD, Biaggioni I, Robertson D, Shelton RC. J Neurol Neurosurg Psychiatry. 2008 Oct 31. PubMed Reversible postural tachycardia syndrome due to inadvertent overuse of Red Bull((R)). Terlizzi R, Rocchi C, Serra M, Solieri L, Cortelli P. Clin Auton Res. 2008 Aug;18(4):221-3. Epub 2008 Aug 5. PubMed Anesthesia for caesarean section in a patient with Ehlers-Danlos syndrome associated with postural orthostatic tachycardia syndrome. Jones TL, Ng C. Int J Obstet Anesth. 2008 Jul 8. PubMed Cardiovascular autonomic reflexes on the postural orthostatic tachycardia syndrome. Benjelloun H, Benjelloun H, Aboudrar S, Coghlan L, Benomar M. Ann Cardiol Angeiol (Paris). 2008 Jun 10. PubMed Postural tachycardia syndrome.Grubb BP. Circulation. 2008 May 27;117(21):2814-7. Full Text Invited Article: Autonomic ganglia: target and novel therapeutic tool.Vernino S, Sandroni P, Singer W, Low PA. Neurology. 2008 May 13;70(20):1926-32. PubMed Orthostatic intolerance and gastrointestinal motility in adolescents with nausea and abdominal pain. Antiel RM, Risma JM, Grothe RM, Brands CK, Fischer PR. J Pediatr Gastroenterol Nutr. 2008 Mar;46(3):285-8. PubMed Postural tachycardia syndrome and coronary artery bridge. Abdelmoneim SS, Moustafa S, Mookadam F. Europace. 2008 Apr;10(4):482-5. Epub 2008 Mar 13. PubMed A Matched Case Control Study of Orthostatic Intolerance in Children/Adolescents With Chronic Fatigue Syndrome. Galland BC, Jackson PM, Sayers RM, Taylor BJ. Pediatr Res. 2008 Feb;63(2):196-202. PubMed Angiotensin II type 1 receptor blockade corrects cutaneous nitric oxide deficit in postural tachycardia syndrome. Stewart JM, Taneja I, Glover J, Medow MS. Am J Physiol Heart Circ Physiol. 2008 Jan;294(1):H466-73. PubMed A multicenter study on treatment of autonomous nerve-mediated syncope in children with beta-receptor blocker. Chen L, DU JB, Zhang QY, Wang C, DU ZD, Wang HW, Tian H, Chen JJ, Wang YL, Hu XF, Li WZ, Han L. Zhonghua Er Ke Za Zhi. 2007 Dec;45(12):885-8. PubMed Takotsubo cardiomyopathy in a patient with postural tachycardia syndrome. Khurana RK. Clin Auton Res. 2007 Oct 19. PubMed Postural tachycardia syndrome with asystole on head-up tilt. Alshekhlee A, Guerch M, Ridha F, McNeeley K, Chelimsky TC. Clin Auton Res. 2007 Oct 19 PubMed Symptom improvement in postural orthostatic tachycardia syndrome with the sinus node blocker ivabradine. Ewan V, Norton M, Newton JL. Europace. 2007 Dec;9(12):1202. Epub 2007 Oct 19. PubMed Sympathovagal balance analysis in idiopathic postural orthostatic tachycardia syndrome. Russo V, De Crescenzo I, Ammendola E, Santangelo L, Calabrò R. Acta Biomed. 2007 Aug;78(2):133-8. PubMed Cardiac denervation in postural tachycardia syndrome.Haensch CA, Lerch H, Jigalin A, Schlemmer H, Isenmann S. Clin Auton Res. 2007 Sep 26. PubMed Postural syncope: mechanisms and management.Vaddadi G, Lambert E, Corcoran SJ, Esler MD. Med J Aust. 2007 Sep 3;187(5):299-304. PubMed Treatment of autonomic neuropathy, postural tachycardia and orthostatic syncope with octreotide LAR. Hoeldtke RD, Bryner KD, Hoeldtke ME, Hobbs G. Clin Auton Res. 2007 Aug 31. PubMed Blood volume perturbations in the postural tachycardia syndrome. Raj SR, Robertson D. Am J Med Sci. 2007 Jul;334(1):57-60. PubMed Reduced stroke volume during exercise in postural tachycardia syndrome. Masuki S, Eisenach JH, Schrage WG, Johnson CP, Dietz NM, Wilkins BW, Sandroni P, Low PA, Joyner MJ. J Appl Physiol. 2007 Jul 12; PubMed Postural orthostatic tachycardia syndrome. Agarwal AK, Garg R, Ritch A, Sarkar P. Postgrad Med J. 2007 Jul;83(981):478-80. PubMed Reduced Central Blood Volume and Cardiac Output, and Increased Vascular Resistance during Static Handgrip Exercise in Postural Tachycardia Syndrome. Stewart J, Taneja I, Medow MS. Am J Physiol Heart Circ Physiol. 2007 Jul 6; PubMed Postural orthostatic tachycardia syndrome: an underrecognized disorder.PandianJD, Dalton K, Henderson RD, McCombe PA. Intern Med J. 2007 Jul 19;37(8):529-535. PubMed Sympathetic neural activity, sex dimorphism, and postural tachycardia syndrome. Bonyhay I, Freeman R. Ann Neurol. 2007 Mar 14. PubMed Postural orthostatic tachycardia syndrome: the Mayo clinic experience. Thieben MJ, Sandroni P, Sletten DM, Benrud-Larson LM, Fealey RD, Vernino S, Lennon VA, Shen WK, Low PA. Mayo Clin Proc. 2007 Mar;82(3):308-13. Full Text The postural tachycardia syndrome. Medow MS, Stewart JM. Cardiol Rev. 2007 Mar-Apr;15(2):67-75. PubMed Pyridostigmine in the treatment of orthostatic intolerance. Gales BJ, Gales MA. Ann Pharmacother. 2007 Feb;41(2):314-8. Epub 2007 Feb 6. PubMed Postural orthostatic tachycardia syndrome: anesthetic implications in the obstetric patient.McEvoy MD, Low PA, Hebbar L. Anesth Analg. 2007 Jan;104(1):166-7. PubMed Episodic hypertension in postural orthostatic tachycardia syndrome. Carvajal Roca E, Torro Domenech I. Lurbe Ferrer E. An Pediatr (Barc). 2006 Nov;65(5):496-9. PubMed Excessive Heart Rate Response to Orthostatic Stress in Postural Tachycardia Syndrome is Not Caused by Anxiety. Masuki S, Eisenach JH, Johnson C, Dietz NM, Benrud-Larson L, Schrage WG, Curry TB, Sandroni P, Low PA, Joyner MJ. J Appl Physiol. 2006 Nov 16. PubMed Treatment of postural tachycardia syndrome: a comparison of octreotide and midodrine. Hoeldtke RD, Bryner KD, Hoeldtke ME, Hobbs G. Clin Auton Res. 2006 Oct 11 PubMed Pharmacokinetics of Pyridostigmine in a Child With Postural Tachycardia Syndrome. Filler G, Gow RM, Nadarajah R, Jacob P, Johnson G, Zhang YL, Christians U. Pediatrics. 2006 Oct 2; PubMed The Postural Tachycardia Syndrome (POTS): Pathophysiology, Diagnosis & Management. Raj SR. Indian Pacing Electrophysiol J. 2006 Apr 1;6(2):84-99. PubMed Experimental induction of panic-like symptoms in patients with postural tachycardia syndrome. Khurana RK. Clin Auton Res. 2006 Aug 16; PubMed Anaesthetic management of a parturient with the postural orthostatic tachycardia syndrome: a case report. Corbett WL, Reiter CM, Schultz JR, Kanter RJ, Habib AS. Br J Anaesth. 2006 May 12; PubMed Postural orthostatic tachycardia syndrome: Dental treatment considerations. Brooks JK, Francis LA. J Am Dent Assoc. 2006 Apr;137(4):488-93. PubMed Familial orthostatic tachycardia. Keller NR, Robertson D. Curr Opin Cardiol. 2006 May;21(3):173-9. PubMed Postural Hypocapnic Hyperventilation is Associated with Enhanced Peripheral Vasoconstriction in Postural Tachycardia Syndrome with Normal Supine Blood Flow. Stewart JM, Medow MS, Cherniack NS, Natelson BH. Am J Physiol Heart Circ Physiol. 2006 Mar 24. PubMed Beta2-adrenoceptor genotype and function affect hemodynamic profile heterogeneity in postural tachycardia syndrome. Jacob G, Garland EM, Costa F, Stein CM, Xie HG, Robertson RM, Biaggioni I, Robertson D. Hypertension. 2006 Mar;47(3):421-7. Epub 2006 Feb 6. PubMed The postural tachycardia syndrome: a concise guide to diagnosis and management. Grubb BP, Kanjwal Y, Kosinski DJ. J Cardiovasc Electrophysiol. 2006 Jan;17(1):108-12. No abstract available. Characterizing Gulf War Illnesses: neurally mediated hypotension and postural tachycardia syndrome. Lucas KE, Armenian HK, Debusk K, Calkins HG, Rowe PC. Am J Med. 2005 Dec;118(12):1421-7. PubMed Orthostatic instability in a population-based study of chronic fatigue syndrome. Jones JF, Nicholson A, Nisenbaum R, Papanicolaou DA, Solomon L, Boneva R, Heim C, Reeves WC. Am J Med. 2005 Dec;118(12):1415. PubMed Increased plasma angiotensin II in postural tachycardia syndrome is related to reduced blood flow and blood volume. Stewart JM, Glover JL, Medow MS. Clin Sci (Lond).2005 Nov 1; PubMed Decreased Microvascular Nitric Oxide-Dependent Vasodilation in Postural Tachycardia Syndrome. Medow MS, Minson CT, Stewart JM. Circulation. 2005 Oct 17; PubMed Inappropriate sinus tachycardia, postural orthostatic tachycardia syndrome, and overlapping syndromes. Brady PA, Low PA, Shen WK. Pacing Clin Electrophysiol. 2005 Oct;28(10):1112-21. PubMed Endothelial NO Synthase Polymorphisms and Postural Tachycardia Syndrome. Garland EM, Winker R, Williams SM, Jiang L, Stanton K, Byrne DW, Biaggioni I, Cascorbi I, Phillips Iii JA, Harris PA, Rudiger H, Robertson D. Hypertension. 2005 Oct 3. Full Text Continuous progression of orthostatic tachycardia as a further feature of the postural tachycardia syndrome. Diehl RR. Pacing Clin Electrophysiol. 2005 Sep;28(9):975-9. PubMed Persistent Splanchnic Hyperemia during Upright tilt in Postural Tachycardia Syndrome. Stewart JM, Medow MS, Glover JL, Montgomery LD. Am J Physiol Heart Circ Physiol. 2005 Sep 2; PubMed Cerebral blood flow during supine rest and the first minute of head-up tilt in patients with orthostatic intolerance. Jauregui-Renaud K, Hermosillo JA, Jardon JL, Marquez MF, Kostine A, Silva MA, Cardenas M. Europace. 2005 Sep;7(5):460-4. PubMed Orthostatic intolerance and syncope associated with Chiari type I malformation. Prilipko O, Dehdashti AR, Zaim S, Seeck M. J Neurol Neurosurg Psychiatry. 2005 Jul;76(7):1034-6. PubMed Splanchnic Hyperemia and Hypervolemia during the Valsalva Maneuver in Postural Tachycardia Syndrome. Stewart JM, Medow MS, Montgomery LD, Glover JL, Millonas MM. Am J Physiol Heart Circ Physiol. 2005 Jun 17. PubMed Pregnancy in postural orthostatic tachycardia syndrome. Glatter KA, Tuteja D, Chiamvimonvat N, Hamdan M, Park JK. Pacing Clin Electrophysiol. 2005 Jun;28(6):591-3. PubMed The value of autonomic testing in postural tachycardia syndrome. A screen of candidate genes and influence of beta(2)-adrenergic receptor genotypes in postural tachycardia syndrome. Auton Neurosci. 2005 Jun 15;120(1-2):97-103. PubMed A screen of candidate genes and influence of beta(2)-adrenergic receptor genotypes in postural tachycardia syndrome. Nickander KK, Carlson PJ, Urrutia RA, Camilleri M, Low PA. Auton Neurosci. 2005 Jun 15;120(1-2):97-103. PubMed Acetylcholinesterase inhibition improves tachycardia in postural tachycardia syndrome. Raj SR, Black BK, Biaggioni I, Harris PA, Robertson D. Circulation. 2005 May 31;111(21):2734-40. PubMed Cerebral Autoregulation Is Preserved In Postural Tachycardia Syndrome (POTS). Schondorf R, Benoit J, Stein R. J Appl Physiol. 2005 Apr 28; PubMed Baroreflex control of muscle sympathetic nerve activity in the postural orthostatic tachycardia syndrome. Muenter Swift N, Charkoudian N, Dotson RM, Suarez GA, Low PA. Am J Physiol Heart Circ Physiol. 2005 Apr 29. PubMed Gastrointestinal symptoms associated with orthostatic intolerance. Sullivan SD, Hanauer J, Rowe PC, Barron DF, Darbari A, Oliva-Hemker M. J Pediatr Gastroenterol Nutr. 2005 Apr;40(4):425-8. PubMed Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Raj SR, Biaggioni I, Yamhure PC, Black BK, Paranjape SY, Byrne DW, Robertson D. Circulation. 2005 Apr 5;111(13):1574-82. PubMed Postural tachycardia syndrome. Makai A, Tahin T, Simor T, Csanadi Z, Rudas L. Orv Hetil. 2005 Mar 13;146(11):515-20. Review. Hungarian. PubMed Clinical analysis and follow-up study of postural orthostatic tachycardia syndrome in 28 pediatric cases. Zhang QY, Du JB, Li WZ. Zhonghua Er Ke Za Zhi. 2005 Mar;43(3):165-9. Chinese. PubMed Hyperadrenergic Postural Tachycardia Syndrome in Mast Cell Activation Disorders. Shibao C, Arzubiaga C, Roberts Ii LJ, Raj S, Black B, Harris P, Biaggioni I. Hypertension. 2005 Feb 14. PubMed Chronic orthostatic intolerance and the postural tachycardia syndrome (POTS). Stewart JM. J Pediatr. 2004 Dec;145(6):725-30. No Abstract Available. Neurocirculatory Abnormalities in Chronic Orthostatic Intolerance. Goldstein DS, Eldadah B, Holmes C, Pechnik S, Moak J, Sharabi Y. Circulation. 2005 Feb 7. PubMed Sympathetic nerve activity in response to hypotensive stress in the postural tachycardia syndrome. Bonyhay I, Freeman R. Circulation. 2004 Nov 16;110(20):3193-8. PubMed Syncope due to autonomic insufficiency syndromes associated with orthostatic intolerance.Grubb B, Dan GA. Rom J Intern Med. 2000-2001;38-39:3-19. PubMed Postural Orthostatic Tachycardia Warrants Investigation of Chiari I Malformation as a Possible Cause. Pasupuleti DV, Vedre A. Cardiology. 2004 Nov 3;103(1):55-56. PubMed [Orthostatic intolerance--prevalence, diagnostic management and its significance for occupational medicine] Winker R. Wien Klin Wochenschr. 2004;116 Suppl 1:40-6. German. PubMed Lower limb compression bandaging is effective in preventing signs and symptoms of seating-induced postural hypotension. Gorelik O, Fishlev G, Almoznino-Sarafian D, Alon I, Weissgarten J, Shteinshnaider M, Chachashvily S, Modai D, Cohen N. Cardiology. 2004;102(4):177-83. PubMed Water drinking in the management of orthostatic intolerance due to orthostatic hypotension, vasovagal syncope and the postural tachycardia syndrome. Mathias CJ, Young TM. Eur J Neurol. 2004 Sep;11(9):613-9. PubMed [Autonomic profile and cardiovascular symptoms] El Honsali I, Benjelloun H, Coghlan CL, Benomar M. Ann Cardiol Angeiol (Paris). 2004 Jun;53(3):137-43. French. PubMed Regional Blood Volume and Peripheral Blood Flow in the Postural Tachycardia Syndrome. Stewart JM, Montgomery LD. Am J Physiol Heart Circ Physiol. 2004 Apr 29. PubMed Asymptomatic Brugada Syndrome Associated with Postural Orthostatic Tachycardia Syndrome: Morishima I, Sone T, Tsuboi H, Mukawa H, Satoda M, Uesugi M. Pacing Clin Electrophysiol. 2004 Apr;27(4):537-540. PubMed Neurally mediated hypotension in systemic lupus erythematosus patients with fibromyalgia. Tang S, Calkins H, Petri M. Rheumatology (Oxford). 2004 Feb 24. PubMed Prospective evaluation of somatic and autonomic small fibers in selected autonomic neuropathies. Singer W, Spies JM, McArthur J, Low J, Griffin JW, Nickander KK, Gordon V, Low PA. Neurology. 2004 Feb 24;62(4):612-8. PubMed Case reports and review of Postural Orthostatic Tachycardia syndrome (POTS). Carothers B, Schmidt L, Puri V. J Ky Med Assoc. 2003 Dec;101(12):549-52. Review. PubMed Correlates of functional disability in patients with postural tachycardia syndrome: preliminary cross-sectional findings. Benrud-Larson LM, Sandroni P, Haythornthwaite JA, Rummans TA, Low PA. Health Psychol. 2003 Nov;22(6):643-8. PubMed Decreased Skeletal Muscle Pump Activity in Postural Tachycardia Syndrome Patients with Low Peripheral Blood Flow. Stewart JM, Medow MS, Montgomery LD, McLeod KD. Am J Physiol Heart Circ Physiol. 2003 Oct 23. PubMed Orthostatic headaches without CSF leak in postural tachycardia syndrome. Mokri B, Low PA. Neurology. 2003 Oct 14;61(7):980-2. PubMed Treatment of postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia. Kanjwal MY, Kosinski DJ, Grubb BP. Curr Cardiol Rep. 2003 Sep;5(5):402-6. PubMed Local Vascular Responses Affecting Blood Flow in Postural Tachycardia Syndrome. Stewart JM, Medow MA, Montgomery LD. Am J Physiol Heart Circ Physiol. 2003 Aug 14. PubMed Dysautonomia in the joint hypermobility syndrome. Gazit Y, Nahir AM, Grahame R, Jacob G. Am J Med. 2003 Jul;115(1):33-40. PubMed Microvascular filtration is increased in postural tachycardia syndrome. Stewart JM. Circulation. 2003 May 19. PMID: 12756156 PubMed Diagnostic management of orthostatic intolerance in the workplace. Winker R, Barth A, Dorner W, Mayr O, Pilger A, Ivancsits S, Ponocny I, Heider A, Wolf C, Rudiger HW. Int Arch Occup Environ Health. 2003 Mar;76(2):143-50. PMID: 12733087 PubMed Contrasting neurovascular findings in chronic orthostatic intolerance and neurocardiogenic syncope.Stewart JM, Weldon A. Clin Sci (Lond). 2003 Apr;104(4):329-40. PMID: 12653674 PubMed Heart rate-dependent electrocardiogram abnormalities in patients with postural tachycardia syndrome. Singer W, Shen WK, Opfer-Gehrking TL, McPhee BR, Hilz MJ, Low PA. Auton Neurosci. 2003 Jan 31;103(1-2):106-13. PMID: 12531404 [PubMed - in process] Clinical and physiological effects of an acute alpha-1 adrenergic agonist and a beta-1 adrenergic antagonist in chronic orthostatic intolerance. Stewart JM, Munoz J, Weldon A. Circulation. 2002 Dec 3;106(23):2946-54. PMID: 12460877 [PubMed - in process] Comparative study of cerebral blood flow between postural tachycardia and neurocardiogenic syncope, during head-up tilt test. Hermosillo AG, Jauregui-Renaud K, Kostine A, Marquez MF, Lara JL, Cardenas M.Europace. 2002 Oct;4(4):369-74. PMID: 12408256 [PubMed - in process] Dysautonomias: clinical disorders of the autonomic nervous system. Goldstein DS, Robertson D, Esler M, Straus SE, Eisenhofer G. Ann Intern Med. 2002 Nov 5;137(9):753-63. PMID: 12416949 [PubMed - in process] Cardiac sympathetic dysautonomia in chronic orthostatic intolerance syndromes. Goldstein DS, Holmes C, Frank SM, Dendi R, Cannon RO 3rd, Sharabi Y, Esler MD, Eisenhofer G. Circulation. 2002 Oct 29;106(18):2358-65. PMID: 12403667 [PubMed - in process] Temporal lobe epilepsy and postural orthostatic tachycardia syndrome (POTS). Seeck M, Blanke O, Zaim S. Epilepsy Behav. 2002 Jun;3(3):285-288. PMID: 12662611Medline Quality of life in patients with postural tachycardia syndrome. Benrud-Larson LM, Dewar MS, Sandroni P, Rummans TA, Haythornthwaite JA, Low PA. Mayo Clin Proc. 2002 Jun;77(6):531-537. PMID: 12059122 [PubMed - indexed for MEDLINE] From PubMed The broader view: catecholamine abnormalities. Vincent S, Robertson D. Clin Auton Res. 2002 May;12 Suppl 1:I44-I49. PMID: 12102462 [PubMed - in process] From PubMed Pooling in chronic orthostatic intolerance: arterial vasoconstrictive but not venous compliance defects. Stewart JM. Circulation. 2002 May 14;105(19):2274-2281. PMID: 12010910 [PubMed - indexed for MEDLINE] From PubMed Polymorphisms of genes encoding components of the sympathetic nervous system but not the renin-angiotensin system as risk factors for orthostatic hypotension. Tabara Y, Kohara K, Miki T. J Hypertens. 2002 Apr;20(4):651-656. PMID: 11910300 [PubMed - in process] From PubMed Water drinking as a treatment for orthostatic syndromes. Shannon JR, Diedrich A, Biaggioni I, Tank J, Robertson RM, Robertson D, Jordan J. Am J Med. 2002 Apr 1;112(5):355-60. PMID: 11904109 [PubMed - in process] From PubMed Evidence of an intrinsic sinus node abnormality in patients with postural tachycardia syndrome. Singer W, Shen WK, Opfer-Gehrking TL, McPhee BR, Hilz MJ, Low PA. Mayo Clin Proc. 2002 Mar;77(3):246-52. PMID: 11888028 [PubMed - indexed for MEDLINE] From PubMed [Syncope - a systematic overview of classification, pathogenesis, diagnosis and management] Hilz MJ, Marthol H, Neundorfer B. Fortschr Neurol Psychiatr. 2002 Feb;70(2):95-107. German. PMID: 11823926 [PubMed - in process] From PubMed The prevalence and association of neck (coat-hanger) pain and orthostatic (postural) hypotension in human spinal cord injury. Cariga P, Ahmed S, Mathias CJ, Gardner BP. Spinal Cord. 2002 Feb;40(2):77-82. PMID: 11926419 [PubMed - in process] From PubMed Increased sympathetic activation in idiopathic orthostatic intolerance: role of systemic adrenoreceptor sensitivity. Jordan J, Shannon JR, Diedrich A, Black BK, Robertson D. Hypertension. 2002 Jan;39(1):173-178. PMID: 11799098 [PubMed - indexed for MEDLINE] From PubMed Inappropriate early hypotension in adolescents: a form of chronic orthostatic intolerance with defective dependent vasoconstriction. Stewart JM, Weldon A. Pediatr Res. 2001 Jul;50(1):97-103. PMID: 11420425 [PubMed - in process] From PubMed Orthostatic intolerance: different abnormalities in the neural sympathetic response to a gravitational stimulus. Furlan R, Magatelli R, Palazzolo L, Rimoldi A, Colombo S, Porta A. Auton Neurosci. 2001 Jul 20;90(1-2):83-8. PMID: 11485296 [PubMed - in process] From PubMed Familial orthostatic tachycardia due to norepinephrine transporter deficiency. Robertson D, Flattem N, Tellioglu T, Carson R, Garland E, Shannon JR, Jordan J, Jacob G, Blakely RD, Biaggioni I. Ann N Y Acad Sci. 2001 Jun;940:527-43. PMID: 11458707 [PubMed - indexed for MEDLINE] From PubMed Reflex vascular defects in the orthostatic tachycardia syndrome of adolescents. Stewart JM, Weldon A. J Appl Physiol. 2001 Jun;90(6):2025-32. PMID: 11356761 [PubMed - indexed for MEDLINE] From PubMed Orthostatic intolerance in Behcet's disease. Tellioglu T, Robertson D. Auton Neurosci. 2001 Jun 20;89(1-2):96-9. PMID: 11474652 [PubMed - in process] From PubMed Cerebral autoregulation in orthostatic intolerance. Schondorf R, Benoit J, Stein R. Ann N Y Acad Sci. 2001 Jun;940:514-26. PMID: 11458706 [PubMed - indexed for MEDLINE] From PubMed Regulation of muscle sympathetic nerve activity after bed rest deconditioning. Pawelczyk JA, Zuckerman JH, Blomqvist CG, Levine BD. Am J Physiol Heart Circ Physiol. 2001 May;280(5):H2230-9. PMID: 11299226 [PubMed - indexed for MEDLINE] From PubMed The relation between lower limb pooling and blood flow during orthostasis in the postural orthostatic tachycardia syndrome of adolescents. Stewart JM, Weldon A. J Pediatr. 2001 Apr;138(4):512-9. PMID: 11295714 [PubMed - indexed for MEDLINE] From PubMed Deterioration of left ventricular chamber performance after bed rest : "cardiovascular deconditioning" or hypovolemia? Perhonen MA, Zuckerman JH, Levine BD. Circulation. 2001 Apr 10;103(14):1851-7. PMID: 11294802 [PubMed - indexed for MEDLINE] From PubMed Cerebrovascular and cardiovascular responses associated with orthostatic intolerance and tachycardia. Harms MP, van Lieshout JJ. Clin Auton Res. 2001 Feb;11(1):35-8. PMID: 11503949 [PubMed - in process] From PubMed The fainting patient: value of the head-upright tilt-table test in adult patients with orthostatic intolerance. Lamarre-Cliche M, Cusson J. CMAJ. 2001 Feb 6;164(3):372-6. PMID: 11232140 [PubMed - indexed for MEDLINE] From PubMed Is sinus node modification appropriate for inappropriate sinus tachycardia with features of postural orthostatic tachycardia syndrome? Shen WK, Low PA, Jahangir A, Munger TM, Friedman PA, Osborn MJ, Stanton MS, Packer DL, Rea RF, Hammill SC. Pacing Clin Electrophysiol. 2001 Feb;24(2):217-30. PMID: 11270703 [PubMed - indexed for MEDLINE] From PubMed Splanchnic-mesenteric capacitance bed in the postural tachycardia syndrome (POTS). Tani H, Singer W, McPhee BR, Opfer-Gehrking TL, Haruma K, Kajiyama G, Low PA. Auton Neurosci. 2000 Dec 28;86(1-2):107-13. PMID: 11269915 [PubMed - indexed for MEDLINE] From PubMed Abnormal baroreflex responses in patients with idiopathic orthostatic intolerance. Farquhar WB, Taylor JA, Darling SE, Chase KP, Freeman R. Circulation. 2000 Dec 19;102(25):3086-91. PMID: 11120699 [PubMed - indexed for MEDLINE] From PubMed Heart rate and plasma cyclic AMP responses to isoproterenol infusion and effect of beta-adrenergic blockade in patients with postural orthostatic tachycardia syndrome. Abe H, Nagatomo T, Kohshi K, Numata T, Kikuchi K, Sonoda S, Mizuki T, Kuroiwa A, Nakashima Y. J Cardiovasc Pharmacol. 2000;36 Suppl 2:S79-82. PMID: 11206727 [PubMed - indexed for MEDLINE] From PubMed Reversible sympathetic vasomotor dysfunction in POTS patients. Freitas J, Santos R, Azevedo E, Costa O, Carvalho M, de Freitas AF. Rev Port Cardiol. 2000 Nov;19(11):1163-70. PMID: 11201632 [PubMed - indexed for MEDLINE] From PubMed Orthostatic intolerance and the postural tachycardia syndrome: genetic and environment pathophysiologies. Neurolab Autonomic Team. Robertson D, Shannon JR, Biaggioni I, Ertl AC, Diedrich A, Carson R, Furlan R, Jacob G, Jordan J. Pflugers Arch. 2000;441(2-3 Suppl):R48-51. PMID: 11200979 [PubMed - indexed for MEDLINE] From PubMed Clinical improvement in patients with orthostatic intolerance after treatment with bisoprolol and fludrocortisone. Freitas J, Santos R, Azevedo E, Costa O, Carvalho M, de Freitas AF. Clin Auton Res. 2000 Oct;10(5):293-9. PMID: 11198485 [PubMed - indexed for MEDLINE] From PubMed Vascular responses to orthostatic stress in patients with postural tachycardia syndrome (POTS), in patients with low orthostatic tolerance, and in asymptomatic controls. Bush VE, Wight VL, Brown CM, Hainsworth R. Clin Auton Res. 2000 Oct;10(5):279-84. PMID: 11198483 [PubMed - indexed for MEDLINE] From PubMed The neuropathic postural tachycardia syndrome. Jacob G, Costa F, Shannon JR, Robertson RM, Wathen M, Stein M, Biaggioni I, Ertl A, Black B, Robertson D. N Engl J Med. 2000 Oct 5;343(14):1008-14. PMID: 11018167 [PubMed - indexed for MEDLINE] From PubMed Vascular perturbations in the chronic orthostatic intolerance of the postural orthostatic tachycardia syndrome. Stewart JM, Weldon A. J Appl Physiol. 2000 Oct;89(4):1505-12. PMID: 11007589 [PubMed - indexed for MEDLINE] From PubMed [Idiopathic postural orthostatic tachycardia syndrome]. Grubb BP. J UOEH. 2000 Sep 1;22(3):239-45. Japanese. PMID: 11019390 [PubMed - as supplied by publisher] Cerebral vasoconstriction precedes orthostatic intolerance after parabolic flight. Serrador JM, Shoemaker JK, Brown TE, Kassam MS, Bondar RL, Schlegel TT. Brain Res Bull. 2000 Sep 1;53(1):113-20. PMID: 11033215 [PubMed - indexed for MEDLINE] From PubMed [Postural orthostatic tachycardia syndrome (POTS): etiology, diagnosis and therapy]. Grubb BP, Klingenheben T. Med Klin. 2000 Aug 15;95(8):442-6. German. PMID: 10985065 [PubMed - indexed for MEDLINE] From PubMed Autonomic nervous system dysfunction in adolescents with postural orthostatic tachycardia syndrome and chronic fatigue syndrome is characterized by attenuated vagal baroreflex and potentiated sympathetic vasomotion. Stewart JM. Pediatr Res. 2000 Aug;48(2):218-26. PMID: 10926298 [PubMed - indexed for MEDLINE] From PubMed Perioperative considerations in a patient with orthostatic intolerance syndrome. McHaourab A, Mazzeo AJ, May JA, Pagel PS. Anesthesiology. 2000 Aug;93(2):571-3. No Abstract Available. PMID: 10910484 [PubMed - indexed for MEDLINE] From PubMed Orthostatic intolerance: a disorder of young women. Ali YS, Daamen N, Jacob G, Jordan J, Shannon JR, Biaggioni I, Robertson D. Obstet Gynecol Surv. 2000 Apr;55(4):251-9. PMID: 10758621 [PubMed - indexed for MEDLINE] From PubMed The postural orthostatic tachycardia syndrome: a potentially treatable cause of chronic fatigue, exercise intolerance, and cognitive impairment in adolescents. Karas B, Grubb BP, Boehm K, Kip K. Pacing Clin Electrophysiol. 2000 Mar;23(3):344-51. PMID: 10750135 [PubMed - indexed for MEDLINE] From PubMed [Syndromes of autonomic dysfunction associated with orthostatic intolerance]. Grubb BP. J UOEH. 2000 Mar 1;22(1):19-31. Japanese. PMID: 10736822 [PubMed - indexed for MEDLINE] From PubMed Mechanisms of blood pressure alterations in response to the Valsalva maneuver in postural tachycardia syndrome. Sandroni P, Novak V, Opfer-Gehrking TL, Huck CA, Low PA. Clin Auton Res. 2000 Feb;10(1):1-5. PMID: 10750636 [PubMed - indexed for MEDLINE] From PubMed Orthostatic intolerance and tachycardia associated with norepinephrine-transporter deficiency. Shannon JR, Flattem NL, Jordan J, Jacob G, Black BK, Biaggioni I, Blakely RD, Robertson D. N Engl J Med. 2000 Feb 24;342(8):541-9. PMID: 10684912 [PubMed - indexed for MEDLINE] From PubMed Blood volume: importance and adaptations to exercise training, environmental stresses, and trauma/sickness. Sawka MN, Convertino VA, Eichner ER, Schnieder SM, Young AJ. Med Sci Sports Exerc. 2000 Feb;32(2):332-48. PMID: 10694114 [PubMed - indexed for MEDLINE] From PubMed [Idiopathic orthostatic tachycardia. Etiology, diagnosis and treatment]. Grubb BP, Blanc JJ. Arch Mal Coeur Vaiss. 2000 Jan;93(1):79-85. French. PMID: 11227722 [PubMed - indexed for MEDLINE] From PubMed [Differential orthostatic dysregulation disorders diagnosis]. Diehl RR, Linden D. Nervenarzt. 1999 Dec;70(12):1044-51. German. PMID: 10637809 [PubMed - indexed for MEDLINE] From PubMed Postural tachycardia syndrome: clinical features and follow-up study. Sandroni P, Opfer-Gehrking TL, McPhee BR, Low PA. Mayo Clin Proc. 1999 Nov;74(11):1106-10. PMID: 10560597 [PubMed - indexed for MEDLINE] From PubMed Interaction of genetic predisposition and environmental factors in the pathogenesis of idiopathic orthostatic intolerance. Jordan J, Shannon JR, Jacob G, Pohar B, Robertson D. Am J Med Sci. 1999 Nov;318(5):298-303. PMID: 10555091 [PubMed - indexed for MEDLINE] From PubMed Putting it together: a new treatment algorithm for vasovagal syncope and related disorders. Bloomfield DM, Sheldon R, Grubb BP, Calkins H, Sutton R. Am J Cardiol. 1999 Oct 21;84(8A):33Q-39Q. PMID: 10568559 [PubMed - indexed for MEDLINE] From PubMed Orthostatic intolerance and chronic fatigue syndrome associated with Ehlers-Danlos syndrome. Rowe PC, Barron DF, Calkins H, Maumenee IH, Tong PY, Geraghty MT. J Pediatr. 1999 Oct;135(4):494-9. PMID: 10518084 [PubMed - indexed for MEDLINE] From PubMed [Syndromes of autonomic insufficiency associated with orthostatic intolerance: classification, diagnostic and therapeutic approach]. Grubb BP, Klingenheben T. Z Kardiol. 1999 Aug;88(8):541-9. German. PMID: 10506389 [PubMed - indexed for MEDLINE] From PubMed Analysis of heart rate variability during head-up tilt testing in a patient with idiopathic postural orthostatic tachycardia syndrome (POTS). Sumiyoshi M, Nakata Y, Mineda Y, Yasuda M, Nakazato Y, Yamaguchi H. Jpn Circ J. 1999 Jun;63(6):496-8. PMID: 10406593 [PubMed - indexed for MEDLINE] From PubMed Cerebrovascular mechanisms in neurocardiogenic syncope with and without postural tachycardia syndrome. Diehl RR, Linden D, Chalkiadaki A, Diehl A. J Auton Nerv Syst. 1999 May 28;76(2-3):159-66. PMID: 10412840 [PubMed - indexed for MEDLINE] From PubMed Diagnosis of tachycardia syndromes associated with orthostatic symptoms. Braune S, Wrocklage C, Schulte-Monting J, Schnitzer R, Lucking CH. Clin Auton Res. 1999 Apr;9(2):97-101. PMID: 10225614 [PubMed - indexed for MEDLINE] From PubMed Cerebrovascular regulation in the postural orthostatic tachycardia syndrome (POTS). Low PA, Novak V, Spies JM, Novak P, Petty GW. Am J Med Sci. 1999 Feb;317(2):124-33. PMID: 10037116 [PubMed - indexed for MEDLINE] From PubMed Clinical and laboratory indices that enhance the diagnosis of postural tachycardia syndrome. Novak V, Novak P, Opfer-Gehrking TL, O'Brien PC, Low PA. Mayo Clin Proc. 1998 Dec;73(12):1141-50. PMID: 9868411 [PubMed - indexed for MEDLINE] From PubMed Autonomic neuropathies. Low PA. Curr Opin Neurol. 1998 Oct;11(5):531-7. PMID: 9848003 [PubMed - indexed for MEDLINE] From PubMed [Orthostatic intolerance. A review and clinical case]. Freitas J, Almeida J, Azevedo E, Carvalho MJ, Costa O, de Freitas AF. Rev Port Cardiol. 1998 Sep;17(9):715-20. Portuguese. PMID: 9834642 [PubMed - indexed for MEDLINE] From PubMed [Orthostatic postural tachycardia: study of 8 patients]. Santiago Perez S, Ferrer Gila T. Med Clin (Barc). 1998 Feb 7;110(4):138-41. Spanish. PMID: 9541904 [PubMed - indexed for MEDLINE] From PubMed The postural orthostatic tachycardia syndrome: a neurocardiogenic variant identified during head-up tilt table testing. Grubb BP, Kosinski DJ, Boehm K, Kip K. Pacing Clin Electrophysiol. 1997 Sep;20(9 Pt 1):2205-12. PMID: 9309745 [PubMed - indexed for MEDLINE] From PubMed Postural tachycardia syndrome: time frequency mapping. Novak V, Novak P, Opfer-Gehrking TL, Low PA. J Auton Nerv Syst. 1996 Dec 14;61(3):313-20. PMID: 8988490 [PubMed - indexed for MEDLINE] From PubMed Certain cardiovascular indices predict syncope in the postural tachycardia syndrome. Sandroni P, Opfer-Gehrking TL, Benarroch EE, Shen WK, Low PA. Clin Auton Res. 1996 Aug;6(4):225-31. 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As with many disorders that have received little research, there are numerous false assumptions made about POTS. Many of these assumptions stem from the lack of information available about this disorder. This page was created in hopes of clarifying some of these false assumptions. Suggestions for this page can be sent to: Dysautonomia Information Network Myth: POTS symptoms only occur while standing. Many patients report symptoms occurring while sitting or lying down. Standing does exacerbate symptoms. Myth: Everyone with POTS faints. Many people with POTS have never fainted. Myth: POTS symptoms are present at all times. The symptoms of POTS can vary greatly from day to day and hour to hour. Myth: Most doctors will be competent in treating POTS patients. Some doctors have never even heard of POTS. It is essential to one's well being to seek out a specialist. Myth: People get POTS because they are lazy and deconditioned. People can get POTS symptoms due to prolonged bed rest, however the symptoms should diminish as the person becomes more active. The origins of chronic orthostatic intolerance are certainly distinct from laziness or deconditioning. To read about the causes of POTS, please see our article "What causes POTS?" https://www.dinet.org/info/pots/what-causes-pots-r98/

As with many disorders that have received little research, there are numerous false assumptions made about POTS. Many of these assumptions stem from the lack of information available about this disorder. This page was created in hopes of clarifying some of these false assumptions. Suggestions for this page can be sent to: Dysautonomia Information Network Myth: POTS symptoms only occur while standing. Many patients report symptoms occurring while sitting or lying down. Standing does exacerbate symptoms. Myth: Everyone with POTS faints. Many people with POTS have never fainted. Myth: POTS symptoms are present at all times. The symptoms of POTS can vary greatly from day to day and hour to hour. Myth: Most doctors will be competent in treating POTS patients. Some doctors have never even heard of POTS. It is essential to one's well being to seek out a specialist. Myth: People get POTS because they are lazy and deconditioned. People can get POTS symptoms due to prolonged bed rest, however the symptoms should diminish as the person becomes more active. The origins of chronic orthostatic intolerance are certainly distinct from laziness or deconditioning.

Ablation of the sinus node may be detrimental to POTS patients. A Mayo Clinic study reported short-term success in five of seven ablated patients with inappropriate sinus tachycardia and postural orthostatic tachycardia features (Shen, Low, Jahangir, Munger, Friedman, Osborn, Stanton, Packer, Rea & Hammill, 2001). However, long-term outcomes were disappointing in these patients. None of the patients experienced complete eradication of symptoms. A follow-up evaluation showed no vast improvement in symptoms, despite better heart rate control. A later publication states "in our laboratory, sinus node modification, total sinus node ablation, or atrioventricular nodal ablation is not recommended for patients with inappropriate sinus tachycardia who have autonomic evidence of postural orthostatic tachycardia" (Shen, 2002). Ablations have reportedly been detrimental to some POTS patients who were misdiagnosed as having inappropriate sinus tachycardia. After the apparently successful elimination of their "sinus tachycardia", they were left with profound orthostatic hypotension (Grubb & Karas, 1999). Alcohol enhances peripheral venous pooling, which will exacerbate hypotension (Grubb & Karas, 1999). Alcohol can also lead to a dehydrated state. Anesthesia can be especially challenging for patients with autonomic dysfunction. When anesthesia is absolutely necessary, an arterial line should be inserted to monitor beat to beat variations in blood pressure. Heart rate should also be constantly monitored, as anesthesia can disturb cardiovascular function. Extra IV fluids are also needed. Read more Bending up and down, as done when picking items up off of the floor, may increase symptoms. It is best to bend at the knee and squat down rather then to bend over forward at the waist. Blowing up balloons is similar to the valsalva maneuver and can exacerbate symptoms in some patients. Certain Foods, such as dairy products,may increase symptoms in some patients. White sugar and other refined carbohydrates can exacerbate hypotension by causing increased dilation in the gut (Mathias, 2000). It is important to identify and avoid food triggers. Studies show that gluten sensitivity may play a role in neurological disorders (Hadjivassiliou, Gibson, Davies-Jones, Lobo, Stephenson & Milford-Ward, 1996). Climbing stairs will make some patients feel worse. Dehydration is one of the worst states a POTS patient can be in. It is very important to always stay well hydrated. Doctors who don't know much about POTS will surely leave patients feeling frustrated. Patients of inexperienced doctors may not receive expert care and may not return to optimum health. Finding an experienced physician is not only desirable, it is a necessity. Physicians who treat dysautonomia can be located on our Physician List. Eating large meals can worsen hypotension in some individuals with dysautonomia (Mathias, 2000). This is because large meals can cause blood to pool excessively in the abdomen. Energy Drinks, such as Red Bull, should be avoided in those with POTS. Postural tachycardia syndrome associated with a vasovagal reaction was recorded in a young volleyball player after an excess intake of Red Bull as a refreshing energy drink (Terlizzi, Rocchi, Serra, Solieri & Cortelli, 2008). Epinephrine is used by doctors and dentists for a variety of reasons. It is commonly used in numbing shots. It is wise to avoid epinephrine as it stimulates the heart. Exercise will make many people with dysautonomia feel worse. Strenuous, exhausting exercise should be avoided. Some patients will experience an exacerbation of symptoms after exercise that may last for a day or more, especially if they suffer from mitochondrial disease. These patients should check with a physician before starting any exercise program. Exercise may be helpful in abating blood from pooling in the limbs. Exercise to build and strengthen the leg muscles can be especially beneficial. Exercise can help POTS patients to avoid becoming deconditioned. A deconditioned state further exacerbates symptoms of orthostatic intolerance. Fatigue enhances peripheral venous pooling (Grubb & Karas, 1999). Those with POTS will do well to live life at their own pace. It is important that patients don't overdo it, as this will make them feel even worse. POTS will require some lifestyle modification. Giving blood can be harmful to people with POTS. Blood pooling in the legs already diminishes the amount of blood flowing to the heart and brain. Further, some patients are hypovolemic (have low blood volume) and need every drop of blood that they have. Blood should not be donated and should only be drawn when necessary for medical reasons. Heat dilates blood vessels and will make POTS symptoms worse. Patients should avoid spending a lot of time outdoors on hot days. POTS patients should not take hot showers/baths or subject their bodies to saunas, hot tubs or greenhouses. Heat enhances peripheral venous pooling (Grubb & Karas, 1999). Holding the arms up in the air can cause problems for some individuals. Holding the arms up requires the heart to work harder to counteract the effects of gravity. This is especially difficult for the heart if there is already excessive venous pooling in the lower limbs. The heart may not be able to effectively pump blood up into raised arms and tachycardia will result from its effort. Lifting objects can aggravate the symptoms of POTS. This may be due to the increased work load on the heart, especially if blood is pooling in the legs. Pooling blood in the lower body makes less blood available for the muscles in the upper body. Also, straining, bending over, coughing and sneezing all raise cerebral spinal fluid pressure. It has been theorized that some POTS patients may experience symptoms while lifting due to changes in cerebral spinal fluid pressure. Many medications will affect autonomic testing results. Some medications that have been reported to significantly affect autonomic testing results include: chlorpromazine, thioridazine, tricyclic antidepressants, bupropion, mirtazepine, vanlafaxine, clonidine, alpha blockers, beta blockers, calcium channel blockers, opiates and topical capsaicin (Sandroni, 1998). Some physicians believe patients should discontinue measures at alleviating symptoms before autonomic testing. By doing so, symptoms are more likely to present during testing. This may help a physician to discern the true nature of a patient's disorder. Numerous over-the-counter products, such as melatonin, can negatively effect the POTS patient. Many products stimulate the heart or lower blood pressure or have diuretic effects, etc. Some products can help one person while hindering another. For example, caffeine can have the positive effect of raising blood pressure in some individuals. However, caffeine also increases the length of time that catecholamines remain active and this can be detrimental to those with a hyperadrenergic state. POTS patients should check with their doctor before taking over-the-counter products. Over-stimulating environments can make POTS symptoms worse. A number of POTS patients report being overly sensitive to bright lights, loud noises and busy environments. Singing has been reported to temporarily worsen symptoms in some individuals. Some pharmacologic agents may cause or worsen orthostatic intolerance. Please check with your physician before taking prescription or over-the-counter medications.Some of themedications that physicians have identified as causing or worsening orthostatic intolerance include: Angiotensin Converting Enzyme Inhibitors (Grubb & Karas, 1999) Alpha Receptor Blockers (Grubb & Karas, 1999) Calcium Channel Blockers (Grubb & Karas, 1999) Beta Blockers (Grubb & Karas, 1999) Phenothiazines (Grubb & Karas, 1999) Tricyclic Antidepressants (Grubb & Karas, 1999) Bromocriptine (Grubb & Karas, 1999) Ethanol (Grubb & Karas, 1999) Opiates (Grubb & Karas, 1999) Diuretics (Grubb & Karas, 1999) Hydralazine (Grubb & Karas, 1999) Ganglionic Blocking Agents (Grubb & Karas, 1999) Nitrates (Grubb & Karas, 1999) Sildenafil Citrate (Grubb & Karas, 1999) MAO Inhibitors (Grubb & Karas, 1999) Olanzapine Stress will often aggravate the symptoms of POTS. The body is continuously adapting to stress, whether it is physical, mental or chemical. POTS patients sometimes lack the ability to correctly process stress due to malfunctioning or excessive functioning of the autonomic nervous system (ANS). Patients may also already have high levels of norepinephrine, which is a stress hormone. POTS patients need to avoid stress (when possible) and live life at their own pace. Specific stresses such as surgery, childbirth and trauma (such as a car accident) have preceded or worsened the development of POTS in some individuals. This is thought to occur due to a number of factors. Surgery, childbirth and trauma can result in excessive blood loss in POTS patients who may already be hypovolemic. It is important for POTS patients to be given extra fluids during these times. Some people theorize that surgery may require a positioning of the neck that can aggravate hind brain compression. While the relationship between hind brain compression and POTS is controversial, it may be wise to avoid these positions (if possible) with POTS patients. Trauma to the neck may also aggravate hind brain compression. Trauma can result in damage to the ANS and also to areas that will secondarily effect the ANS. Likewise, some believe the straining of bearing down during childbirth can aggravate hind brain compression and effect the ANS. POTS occurring as a result of the nutcracker phenomenon is also more prevalent after childbirth. Hormonal shifts have been theorized to contribute to the development or worsening of POTS symptoms after childbirth as well. Travel by airplane is challenging for dysautonomics and may increase symptoms. Airplane cabins are pressurized to about 6,500 feet, which is high enough to cause some dysautonomia patients to hyperventilate. Hyperventilating makes a patient more likely to get symptoms of sympathetic activation (Robertson, 2002). Those with POTS do need to know that the air in an airplane is some of the driest in the world. Flying can have dehydrating effects in normal individuals. How much more so flying might dehydrate someone with low blood volume. Everyone should be well hydrated before boarding a plane. Also, normal people sometimes have trouble with blood pooling in their legs during flights. Rarely, this can lead to the development of blood clots. Patients prone to pooling blood may want to wear compression stockings when flying. Patients may also want to request a bulkhead seat, as this will give them more room to elevate their legs. References 1. Grubb, B. P. (2002, October). The heterogeneity of symptoms related to dysautonomia. Symposium conducted at the meeting of the National Dysautonomia Research Foundation Northwest Ohio Support Group. Toledo, Ohio. 2. Grubb, B. P., & Karas, B. (1999). Clinical disorders of the autonomic nervous system associated with orthostatic intolerance: an overview of classification, clinical evaluation, and management. Pacing and Clinical Electrophysiology, 22, 798-810. Full text: http://www.ndrf.org/PDF%20Files/disorders.PDF 3. Hadjivassiliou, M., Gibson, A., Davies-Jones, G. A., Lobo, A.J., Stephenson, T.J., & Milford-Ward, A. (1996). Does cryptic gluten sensitivity play a part in neurological illness? Lancet, 10, 369-371. PMID: 8598704 [PubMed - indexed for MEDLINE] 4. Mathias, C. J. (2000, July). Other autonomic disorders. National Dysautonomia Research Foundation Patient conference. Minneapolis, Minnesota. 5. Robertson, D. (2002, July). Drug Therapy. National Dysautonomia Research Foundation Patient conference. Washington, DC. 6. Sandroni, P. (1998, November/December). Testing the autonomic nervous system. In C. B. Berde, & M. C. Rowbotham (Eds.) International Association for the Study of Pain: Technical Corner From IASP Newsletter. Full Text 7. Shen, W. K. (2002). Modification and ablation for inappropriate sinus tachycardia: current status. Cardiac Electrophysiology Review. 6(4), 349-355. PubMed 8. Shen, W. K., Low, P.A., Jahangir, A., Munger, T. M., Friedman, P. A., Osborn, M. J., Stanton, M. S., Packer, D. L., Rea, R. F., Hammill, S. C. (2001). Is sinus node modification appropriate for inappropriate sinus tachycardia with features of postural orthostatic tachycardia syndrome? Pacing & Clinical Electrophysiology, 24(2), 217-230. PubMed 9. Terlizzi, R., Rocchi, C., Serra, M., Solieri, L., Cortelli, P. (2008). Reversible postural tachycardia syndrome due to inadvertent overuse of Red Bull. Clinical Autonomic Research, 18(4), 221-223. PubMed

Ablation of the sinus node may be detrimental to POTS patients. A Mayo Clinic study reported short-term success in five of seven ablated patients with inappropriate sinus tachycardia and postural orthostatic tachycardia features (Shen, Low, Jahangir, Munger, Friedman, Osborn, Stanton, Packer, Rea & Hammill, 2001). However, long-term outcomes were disappointing in these patients. None of the patients experienced complete eradication of symptoms. A follow-up evaluation showed no vast improvement in symptoms, despite better heart rate control. A later publication states "in our laboratory, sinus node modification, total sinus node ablation, or atrioventricular nodal ablation is not recommended for patients with inappropriate sinus tachycardia who have autonomic evidence of postural orthostatic tachycardia" (Shen, 2002). Ablations have reportedly been detrimental to some POTS patients who were misdiagnosed as having inappropriate sinus tachycardia. After the apparently successful elimination of their "sinus tachycardia", they were left with profound orthostatic hypotension (Grubb & Karas, 1999). Alcohol enhances peripheral venous pooling, which will exacerbate hypotension (Grubb & Karas, 1999). Alcohol can also lead to a dehydrated state. Anesthesia can be especially challenging for patients with autonomic dysfunction. When anesthesia is absolutely necessary, an arterial line should be inserted to monitor beat to beat variations in blood pressure. Heart rate should also be constantly monitored, as anesthesia can disturb cardiovascular function. Extra IV fluids are also needed. Read more Bending up and down, as done when picking items up off of the floor, may increase symptoms. It is best to bend at the knee and squat down rather then to bend over forward at the waist. Blowing up balloons is similar to the valsalva maneuver and can exacerbate symptoms in some patients. Certain Foods, such as dairy products,may increase symptoms in some patients. White sugar and other refined carbohydrates can exacerbate hypotension by causing increased dilation in the gut (Mathias, 2000). It is important to identify and avoid food triggers. Studies show that gluten sensitivity may play a role in neurological disorders (Hadjivassiliou, Gibson, Davies-Jones, Lobo, Stephenson & Milford-Ward, 1996). Climbing stairs will make some patients feel worse. Dehydration is one of the worst states a POTS patient can be in. It is very important to always stay well hydrated. Doctors who don't know much about POTS will surely leave patients feeling frustrated. Patients of inexperienced doctors may not receive expert care and may not return to optimum health. Finding an experienced physician is not only desirable, it is a necessity. Physicians who treat dysautonomia can be located on our Physician List. Eating large meals can worsen hypotension in some individuals with dysautonomia (Mathias, 2000). This is because large meals can cause blood to pool excessively in the abdomen. Energy Drinks, such as Red Bull, should be avoided in those with POTS. Postural tachycardia syndrome associated with a vasovagal reaction was recorded in a young volleyball player after an excess intake of Red Bull as a refreshing energy drink (Terlizzi, Rocchi, Serra, Solieri & Cortelli, 2008). Epinephrine is used by doctors and dentists for a variety of reasons. It is commonly used in numbing shots. It is wise to avoid epinephrine as it stimulates the heart. Exercise will make many people with dysautonomia feel worse. Strenuous, exhausting exercise should be avoided. Some patients will experience an exacerbation of symptoms after exercise that may last for a day or more, especially if they suffer from mitochondrial disease. These patients should check with a physician before starting any exercise program. Exercise may be helpful in abating blood from pooling in the limbs. Exercise to build and strengthen the leg muscles can be especially beneficial. Exercise can help POTS patients to avoid becoming deconditioned. A deconditioned state further exacerbates symptoms of orthostatic intolerance. Fatigue enhances peripheral venous pooling (Grubb & Karas, 1999). Those with POTS will do well to live life at their own pace. It is important that patients don't overdo it, as this will make them feel even worse. POTS will require some lifestyle modification. Giving blood can be harmful to people with POTS. Blood pooling in the legs already diminishes the amount of blood flowing to the heart and brain. Further, some patients are hypovolemic (have low blood volume) and need every drop of blood that they have. Blood should not be donated and should only be drawn when necessary for medical reasons. Heat dilates blood vessels and will make POTS symptoms worse. Patients should avoid spending a lot of time outdoors on hot days. POTS patients should not take hot showers/baths or subject their bodies to saunas, hot tubs or greenhouses. Heat enhances peripheral venous pooling (Grubb & Karas, 1999). Holding the arms up in the air can cause problems for some individuals. Holding the arms up requires the heart to work harder to counteract the effects of gravity. This is especially difficult for the heart if there is already excessive venous pooling in the lower limbs. The heart may not be able to effectively pump blood up into raised arms and tachycardia will result from its effort. Lifting objects can aggravate the symptoms of POTS. This may be due to the increased work load on the heart, especially if blood is pooling in the legs. Pooling blood in the lower body makes less blood available for the muscles in the upper body. Also, straining, bending over, coughing and sneezing all raise cerebral spinal fluid pressure. It has been theorized that some POTS patients may experience symptoms while lifting due to changes in cerebral spinal fluid pressure. Many medications will affect autonomic testing results. Some medications that have been reported to significantly affect autonomic testing results include: chlorpromazine, thioridazine, tricyclic antidepressants, bupropion, mirtazepine, vanlafaxine, clonidine, alpha blockers, beta blockers, calcium channel blockers, opiates and topical capsaicin (Sandroni, 1998). Some physicians believe patients should discontinue measures at alleviating symptoms before autonomic testing. By doing so, symptoms are more likely to present during testing. This may help a physician to discern the true nature of a patient's disorder. Numerous over-the-counter products, such as melatonin, can negatively effect the POTS patient. Many products stimulate the heart or lower blood pressure or have diuretic effects, etc. Some products can help one person while hindering another. For example, caffeine can have the positive effect of raising blood pressure in some individuals. However, caffeine also increases the length of time that catecholamines remain active and this can be detrimental to those with a hyperadrenergic state. POTS patients should check with their doctor before taking over-the-counter products. Over-stimulating environments can make POTS symptoms worse. A number of POTS patients report being overly sensitive to bright lights, loud noises and busy environments. Singing has been reported to temporarily worsen symptoms in some individuals. Some pharmacologic agents may cause or worsen orthostatic intolerance. Please check with your physician before taking prescription or over-the-counter medications.Some of themedications that physicians have identified as causing or worsening orthostatic intolerance include: Angiotensin Converting Enzyme Inhibitors (Grubb & Karas, 1999) Alpha Receptor Blockers (Grubb & Karas, 1999) Calcium Channel Blockers (Grubb & Karas, 1999) Beta Blockers (Grubb & Karas, 1999) Phenothiazines (Grubb & Karas, 1999) Tricyclic Antidepressants (Grubb & Karas, 1999) Bromocriptine (Grubb & Karas, 1999) Ethanol (Grubb & Karas, 1999) Opiates (Grubb & Karas, 1999) Diuretics (Grubb & Karas, 1999) Hydralazine (Grubb & Karas, 1999) Ganglionic Blocking Agents (Grubb & Karas, 1999) Nitrates (Grubb & Karas, 1999) Sildenafil Citrate (Grubb & Karas, 1999) MAO Inhibitors (Grubb & Karas, 1999) Olanzapine Stress will often aggravate the symptoms of POTS. The body is continuously adapting to stress, whether it is physical, mental or chemical. POTS patients sometimes lack the ability to correctly process stress due to malfunctioning or excessive functioning of the autonomic nervous system (ANS). Patients may also already have high levels of norepinephrine, which is a stress hormone. POTS patients need to avoid stress (when possible) and live life at their own pace. Specific stresses such as surgery, childbirth and trauma (such as a car accident) have preceded or worsened the development of POTS in some individuals. This is thought to occur due to a number of factors. Surgery, childbirth and trauma can result in excessive blood loss in POTS patients who may already be hypovolemic. It is important for POTS patients to be given extra fluids during these times. Some people theorize that surgery may require a positioning of the neck that can aggravate hind brain compression. While the relationship between hind brain compression and POTS is controversial, it may be wise to avoid these positions (if possible) with POTS patients. Trauma to the neck may also aggravate hind brain compression. Trauma can result in damage to the ANS and also to areas that will secondarily effect the ANS. Likewise, some believe the straining of bearing down during childbirth can aggravate hind brain compression and effect the ANS. POTS occurring as a result of the nutcracker phenomenon is also more prevalent after childbirth. Hormonal shifts have been theorized to contribute to the development or worsening of POTS symptoms after childbirth as well. Travel by airplane is challenging for dysautonomics and may increase symptoms. Airplane cabins are pressurized to about 6,500 feet, which is high enough to cause some dysautonomia patients to hyperventilate. Hyperventilating makes a patient more likely to get symptoms of sympathetic activation (Robertson, 2002). Those with POTS do need to know that the air in an airplane is some of the driest in the world. Flying can have dehydrating effects in normal individuals. How much more so flying might dehydrate someone with low blood volume. Everyone should be well hydrated before boarding a plane. Also, normal people sometimes have trouble with blood pooling in their legs during flights. Rarely, this can lead to the development of blood clots. Patients prone to pooling blood may want to wear compression stockings when flying. Patients may also want to request a bulkhead seat, as this will give them more room to elevate their legs. References 1. Grubb, B. P. (2002, October). The heterogeneity of symptoms related to dysautonomia. Symposium conducted at the meeting of the National Dysautonomia Research Foundation Northwest Ohio Support Group. Toledo, Ohio. 2. Grubb, B. P., & Karas, B. (1999). Clinical disorders of the autonomic nervous system associated with orthostatic intolerance: an overview of classification, clinical evaluation, and management. Pacing and Clinical Electrophysiology, 22, 798-810. Full text: http://www.ndrf.org/PDF%20Files/disorders.PDF 3. Hadjivassiliou, M., Gibson, A., Davies-Jones, G. A., Lobo, A.J., Stephenson, T.J., & Milford-Ward, A. (1996). Does cryptic gluten sensitivity play a part in neurological illness? Lancet, 10, 369-371. PMID: 8598704 [PubMed - indexed for MEDLINE] 4. Mathias, C. J. (2000, July). Other autonomic disorders. National Dysautonomia Research Foundation Patient conference. Minneapolis, Minnesota. 5. Robertson, D. (2002, July). Drug Therapy. National Dysautonomia Research Foundation Patient conference. Washington, DC. 6. Sandroni, P. (1998, November/December). Testing the autonomic nervous system. In C. B. Berde, & M. C. Rowbotham (Eds.) International Association for the Study of Pain: Technical Corner From IASP Newsletter. Full Text 7. Shen, W. K. (2002). Modification and ablation for inappropriate sinus tachycardia: current status. Cardiac Electrophysiology Review. 6(4), 349-355. PubMed 8. Shen, W. K., Low, P.A., Jahangir, A., Munger, T. M., Friedman, P. A., Osborn, M. J., Stanton, M. S., Packer, D. L., Rea, R. F., Hammill, S. C. (2001). Is sinus node modification appropriate for inappropriate sinus tachycardia with features of postural orthostatic tachycardia syndrome? Pacing & Clinical Electrophysiology, 24(2), 217-230. PubMed 9. Terlizzi, R., Rocchi, C., Serra, M., Solieri, L., Cortelli, P. (2008). Reversible postural tachycardia syndrome due to inadvertent overuse of Red Bull. Clinical Autonomic Research, 18(4), 221-223. PubMed

The contents of this Web page are provided for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis or treatment. Please keep in mind that new treatments are continually emerging and some of the older treatments may rarely be used. Your physician may prescribe medication to decrease the symptoms of POTS. Doctors admit that treatment can be a challenge and that no single therapy is uniformly successful. Medications that are useful in some patients may have no effect in others (Jacob & Biaggioni, 1999). Occasionally medications can worsen symptoms. Medications used to treat POTS include the following: Anti-arrhythmic drugs, such as disopyramide (norpace), have been used to treat POTS patients. However, studies have shown that some anti-arrhythmic drugs may increase the risk of death, and they are usually used only to treat life-threatening arrhythmias. Benzodiazepines, such as Clonazepam (klonopin) or alprazolam (xanax), are not used as a first-line of treatment and can worsen tachycardia and hypotension. However, they may be helpful in select patients. Klonapin has been shown to be effective in the treatment of some patients with neurally mediated syncope (Kadri, Hee, Rovang, Mohiuddin, Ryan, Ashraf, Huebert & Hilleman, 1999). These drugs are central nervous system depressants. They are thought to enhance the effect of gaba, an inhibitory neurotransmitter. Benzodiazepines should be used with caution, as they are highly addictive. Some physicians do not advocate their use. Beta Blockers are especially useful in those with elevated norepinephrine levels, beta-receptor supersensitivity and a hyperadrenergic state. Beta blockers can exacerbate hypotension and are not well tolerated by some dysautonomics. Beta blockers need to be used with caution, as they are known to reduce plasma renin activity. Research shows that hypovolemic orthostatic intolerant patients commonly have inappropriately low levels of plasma renin activity (Jacob, Robertson, Mosqueda-Garcia, Ertl, Robertson & Biaggioni, 1997). Reduced plasma renin activity may be an important pathophysiologic component of the syndrome of orthostatic intolerance (Jacob et al., 1997). Hence, some POTS patients may have low plasma renin activity that is contributing to their disorder. Beta blockers may further lower plasma renin activity in these patients. Therefore, the use of beta blockers in some hypovolemic patients may be counterproductive. Beta blockers should be used with caution, if at all, in those with mast-cell activation disorders (Shibao, Arzubiaga, Roberts, Raj, Black, Harris & Biaggioni, 2005). Beta blockers may trigger mast-cell activation. Cerefolin is a vitamin supplement that may help patients combat fatigue and feel more alert. Clonidine (Catepres) is a centrally acting alpha-agonist agent. Clonidine inhibits sympathetic outflow (Grubb & McMann, 2001, p. 117). It can stabilize heart rate and blood pressure in patients with post-ganglionic sympathetic involvement (Gaffney, Lane, Pettinger & Blomqvist, 1983). Clonidine will actually display a vasoconstrictive effect in these patients. Clonidine is started at 0.1 mg a day and titrated upward (Grubb, Kanjwal & Kosinski, 2006). It is available in a long-acting patch form. DDAVP (Desmopressin) is used to help patients retain water. DDAVP can raise blood pressure and seems to be especially useful in lessening morning hypotension. It is a man made copy of the anti-diuretic hormone vassopressin. Vassopressin and DDAVP stimulate the kidneys to concentrate urine. Droxidopa (Northera) Droxidopa, a norepinephrine (NE) precursor, improves symptoms of neurogenic orthostatic hypotension (nOH) by replenishing NE levels. Central NE effects are poorly described but may offer potential benefits given the pathophysiologic progression of alpha-synuclein related disorders. Erythropoietin raises blood pressure and red cell mass. Red blood cell volume has been found to be low in POTS patients (Raj, Biaggioni, Yamhure, Black, Paranjape, Byrne & Robertson, 2005). Erythropoietin is also a potent vasoconstrictor and is quite useful in the treatment of orthostatic disorders (Grubb, Kanjwal & Kosinski, 2006). There may be an impairment in erythropoietin production and/or function in some individuals with POTS. Erythropoietin reportedly works in 80% of patients (Grubb, 2002). One study showed that erythropoietin administration led to dramatic improvements in some patients with orthostatic hypotension (Hoeldtke & Streeten, 1993). However, a later study of (only) 8 patients with orthostatic tachycardia reported that erythropoietin did not help the tachycardia (Hoeldtke, Horvath & Bryner, 1995). Erythropoietin is not commonly used because it has to be injected and is expensive. Procrit is a common medication that increases erythropoietin, which in turn increases red blood cell mass. Patients treated with erythropoietin may need iron supplementation as their hematocrit rises. Prior to starting erythropoietin, a complete serum blood count (CBC) as well as a serum iron, total iron binding capacity, and ferritin level should be obtained by one's physician (Grubb, Kanjwal & Kosinski, 2006). Erythropoietin can be employed as long as the hematocrit (HCT) is less than 50, and patients appear to achieve the best hemodynamic effect when the HCT is in the low to mid-40 range. The usual starting dose of erythropoietin is 10,000 units injected subcutaneously once weekly, and it usually takes 4-6 weeks to see the full effects of this medication (Grubb, Kanjwal & Kosinski, 2006). Patients should have their HCT checked monthly to make sure it is below 50. Florinef (Fludrocortisone) increases plasma volume. It helps the body to retain salt and water. It also sensitizes blood vessels so that they can constrict more easily (Haran, 2004). Some doctors administer salt tablets with florinef. This is because the effectiveness of Florinef depends upon salt intake. Florinef can deplete potassium and magnesium and supplements may be required. Florinef increases intracranial pressure and should not be used in patients with hind brain compression. Numerous symptoms of sympathetic overactivity are enhanced by Florinef and some people develop severe headaches as a result of treatment (Schondorf & Freeman, 1999). Florinef is a mineralocorticoid and, like beta blockers, can reduce levels of plasma renin activity (Jacob et al., 1997). Reduced levels of plasma renin activity correlate with the hypovolemia observed in some POTS patients. Florinef may be a counterproductive treatment in these patients. Usually, POTS patients are prescribed 0.1-0.2 mg of fludrocortisone daily. The dose should never exceed 0.4 mg orally each day as adrenal suppression may occur (Grubb, Kanjwal & Kosinski, 2006). Ivabradine, a sinus node blocker, has reportedly helped some POTS patients experience less symptoms. Ivabradine is sometimes used as an alternative to beta-blockers because it results in heart rate reduction without vasodilation, sexual disturbances, ornegative inotropic effects. Labetalol is sometimes used in POTS patients because it induces both alpha- and beta-blockade. Dosages of 100-400 mg orally twice a day may be employed (Grubb, Kanjwal & Kosinski, 2006). Carvedilol works in a similar fashion to labetalol and is also sometimes employed as a treatment for POTS. Methyldopa is helpful in select POTS patients (Grubb, Kanjwal & Kosinski, 2006). Mestinon (Pyridostigmine Bromide) has traditionally been used to treat myasthenia gravis, but is now sometimes being used to treat POTS patients (Grubb, 2002). Mestinon works by inhibiting the breakdown of acetylcholine. Acetylcholine is the main chemical messenger of the parasympathetic nervous system. Some POTS patients may have immune systems that are mistakenly making antibodies that are plugging up acetylcholine receptors (Grubb, 2002). Mestinon works to unplug these receptors by allowing more acetylcholine to remain at the neuromuscular junction. Mestinon is particulary useful in patients who have the postviral, paraneoplastic or autoimmune forms of POTS. Mestinon is usually started at 30 mg orally twice a day, titrating to 60 mg orally twice daily, if necessary (Grubb, Kanjwal & Kosinski, 2006). Motrin (Ibuprofen) or Indocin (Indomethacin) might be beneficial treatments for patients with postprandial hypotension (Hilz, Marthol & Neundorfer, 2002). Postprandial hypotension refers to low blood pressure occurring after meals. Motrin and indocin block the blood pressure lowering effects of prostaglandins (Hain, 2001). Studies have suggested that nonsteroidal anti-inflammatory drugs may also lower one's risk of developing Alzheimer's disease(in t' Veld, Ruitenberg, Hofman, Launer, van Duijn, Stijnen, Breteler & Stricker, 2001). However, long term use of nonsteroidal anti-inflammatory drugs can have serious side effects. Phenobarbital is a central nervous system depressant. It can be useful in the hyperadrenergic form of dysautonomia. However, phenobarbital is a barbiturate and people can become addicted to this drug. Barbiturates can also cause fainting (Grubb & McMann, 2001, p. 109). Prednisone, plasma exchange or intravenous gamma globulin may be used in patients who are in the acute post-viral phase of the illness (Low, Schondorf, Novak, Sandroni, Opfer-Gehrking & Novak, 1997, p. 694). These treatments are most likely to be effective in patients displaying evidence of an acute autonomic neuropathy. Saline has shown to be very beneficial in decreasing POTS symptoms. It is an inexpensive treatment with few side effects. However, saline must be given through an IV, which is time consuming and may require trips to the doctor's office. Some of the most severely affected patients report having a peripherally inserted central catheter (PICC line) inserted so that IVs can be administered at home. However, some physicians do not believe the benefits outweigh the possible risks associated with a PICC line. Selective Serotonin Reuptake Inhibitors (SSRI's) are sometimes used to treat those with autonomic disorders. SSRI's are used because serotonin is the principal neurotransmitter that the brain uses to govern autonomic control, in particular to govern blood pressure (Haran, 2004). Studies have shown that some patients with autonomic disorders may have disturbances in central serotonin production and regulation (Grubb & Karas, 1998). SSRI treatment can suppress the sympathetic nervous system (Shores, Pascualy, Lewis, Flatness & Veith, 2001). Venlafaxine is particularly effective, possibly due to its actions on norepinephrine as well as serotonin. It has been reported that SSRI's may be effective in treating the chest pain that is associated with dysautonomia (Low, 2000). However, the FDA has issued a public health advisory regarding antidepressants, and they should be used with caution. Sleep medications are used by some POTS patients. A number of patients have significant sleep disturbances (Low, 2000). Some patients report successfully using natural alternatives to sleep medication. Herbal remedies should be used with caution and under a physician's supervision, as there are known risks with some OTC sleep aids. For example, the FDA has issued warnings regarding Kava Kava and melatonin supplements have been shown to worsen orthostatic intolerance. Stopping menstruation through the use of birth control pills has reportedly helped some patients feel better. Many women report a worsening of symptoms around menstruation. Stopping menstruation is somewhat controversial, and not all physicians advocate it. Vasoconstrictors such as ergotamine, midodrine, octreotide, ephedrine, pseudoephedrine, yohimbine, theophylline and ritalin improve venous tone which decreases pooling blood. Midodrine is particularly useful in patients with peripheral denervation (Low, 2000). Midodrine is usually started at 5 mg orally three times a day and can be titrated up to 15-20 mg orally four times a day, if necessary (Grubb, Kanjwal & Kosinski, 2006). Midodrine can be used on an as needed basis. Theoretically, continuous use of midodrine could result in constriction of blood volume due to chronic sympathetic activation (Jacob & Biaggioni, 1999). Octreotide is especially useful in preventing vasodilation in the gut, thereby reducing splanchnic pooling. Its actions help to prevent postprandial hypotension (low blood pressure after meals). Octreotide inhibits the release of a variety of gastrointestinal peptides and also may reduce postural and exercise induced hypotension (Mathias, 2003). Octreotide does not often appear to enhance supine nocturnal hypertension, however one study reports that it is a possible side effect (Hoeldtke, Bryner, Hoeldtke & Hobbs, 2007). Octreotide is administered by subcutaneous injection starting at 50 µg 2-3 times a day, and dosages may be titrated up to 100-200 µg three times a day (Grubb, Kanjwal & Kosinski, 2006). A long-acting injectable form has also been developed. Ephedrine is not often used due to its short half-life and undesirable B-adrenergic actions (Jacob & Biaggioni, 1999). Ephedrine can cause tachycardia. Theophyllineis primarily used in asthma patients. One of its effects is to increase vasoconstriction, therefore theophylline is sometimes used to treat dysautonomia (Grubb & McMann, 2001, p. 116). Ritalin increases peripheral vascular resistance via alpha receptor stimulation (Grubb, Kosinski, Mouhaffel & Pothoulakis, 1996). Ritalin is prescribed by some physicians, but can be addictive. Wellbutrin (Bupropion) is a central nervous system stimulant. It is a dopamine agonist and also a weak blocker of the neuronal uptake of serotonin and norepinephrine. Wellbutrin is not habit forming and works immediately. Wellbutrin can sometimes be used to combat the fatigue that plagues POTS patients. There are also many non-pharmaceutical methods to decrease the symptoms of POTS. These include the following: Butcher's broom may lessen orthostatic hypotension in some patients (Redman, 2000). Studies show that butcher's broom does not cause supine hypertension and that it can alleviate the worsening of symptoms in hot environments. Butcher's broom is a vasoconstrictor that reduces capillary permeability. Butcher's broom has been used as a diuretic, so patient's need to be especially cautious about taking it. Butcher's broom should only be taken under a doctor's supervision. Changing eating habits and diet can help relieve hypotension. Patients should eat frequent small meals instead of three large meals a day. This will help reduce the amount of blood needed for digestion. Hence, more blood will be available for the brain and heart. Refined carbohydrates, such as white flour and sugar, can exacerbate hypotension (Mathias, 2000). There are patients that report a worsening of symptoms when eating certain foods, such as dairy products. It is important for each patient to identify and avoid their food triggers. Cooling devices can help POTS patients. There are many different types of personal cooling vests available that may help patients tolerate hot environments. Countermaneuvers can help to decrease symptoms by lessening the amount of blood that pools in one's legs. Useful countermaneuvers include: standing with your legs crossed, sitting in a low chair, sitting in the knee to chest position, leaning forward with your hands on your knees when sitting and tightening the buttocks, thigh and leg muscles when standing (particularly when standing for any length of time). Research shows that tensing the leg muscles while standing enhances brain blood flow and reduces sympathetic activity (van Lieshout Pott, Madsen, van Goudoever & Secher, 2001.) Squatting can also be a useful countermaneuver, although some patients report an increase in symptoms after squatting. Compression devices, such as abdominal binders and compression stockings, help to reduce the amount of pooling blood. Compression stockings should be at least 30-40 mm Hg and will work best if they are waist high (Grubb & Karas, 1999). Compression stockings should be fitted to achieve the greatest benefit. Many insurance plans will cover the cost of prescribed compression stockings if purchased through a medical supply company. They are also available without prescription through many online retailers. One POTS patient has found relief of symptoms by wearing a G-suit, and she has created a website that details her experience with this compression device. Her website begins "G-suits are pants that can save the life of a fighter pilot. G-suits are pants that have 'saved' my life too." Click here to visit this patient's informative website. Correcting anemia has been shown to improve orthostatic tolerance (Low, 1994). Elevating the head of the bed 4-12 inches has helped some POTS patients become less symptomatic. It has been reported that elevating the head of the bed generates mechanisms that expand plasma volume (Low, 2000). Exercise can be helpful to those with dysautonomia. It is important that one does not let their body become deconditioned, as this will exacerbate symptoms. Tightening and building the leg muscles will help them to squeeze pooling blood back to the upper part of the body. Swimming in water has been reported to help many dysautonomics, however no one who faints should go into water alone. Yaz Exercises and recumbent stationary bikes may be beneficial to some patients with POTS. Aerobic exercise performed for 20 minutes a day, three times a week, is sometimes recommended for patients who can tolerate it (Grubb, Kanjwal & Kosinski, 2006). Getting plenty of rest is very important for those with POTS. It has been reported that some POTS patients have significant sleep disturbances (Low, 2000). These patients may require more sleep than the average person. Heart rate watches can help patients identify situations that trigger heart rate increases. These watches are available at sports stores or can be purchased on the Internet. Ice has reportedly helped some POTS patients. Rubbing ice on the body, especially on the bottom of the feet or neck, may help some POTS patients ward off an episode. Increasing fluids helps many people with POTS to feel better. Many POTS patients report Gatorade or electrolyte solutions to be particularly helpful. Drinking water has been shown to moderately reduce orthostatic tachycardia in patients with idiopathic orthostatic intolerance (Shannon, Diedrich, Biaggioni, Tank, Robertson, Robertson & Jordan, 2002). Drinking large amounts of water helps to raise blood pressure (Jordan, Shannon, Grogan, Biaggioni & Robertson, 1999). Consuming large amounts of water increases blood volume, which is especially useful in the hypovolemic and those with pooling blood. Some patients report that drinking water before getting out of bed in the morning helps decrease symptoms. Physicians suggest patients drink eight eight-ounce glasses of water daily (Low, 2000). Patients should not drink excessive amounts of water because doing so can cause essential electrolytes to become diluted in the bloodstream, which may affect heart rhythm. Increasing salt is a treatment used for many people with POTS, however salt is not recommended for all patients. While normal subjects reduce urinary sodium excretion on assumption of upright posture, patients with orthostatic intolerance do so ineffectively (Vanderbilt University Autonomic Dysfunction Center, 1999). Impaired renal sodium conservation can contribute to hypovolemia (Streeten, 1999). One study found POTS patients to have inappropriately low levels of renin and aldosterone, two hormones that promote sodium retention and increase plasma volume (Raj, Biaggioni, Yamhure, Black, Paranjape, Byrne & Robertson, 2005). Renin and aldosterone are both regulated by the kidney. Increasing salt is an effective way to raise blood pressure in many patients with orthostatic hypotension. Salt helps to expand blood volume. A number of patients find salt tablets and/or electrolyte solutions to be helpful. Some physicians suggest patients who benefit from salt take in 10-15 grams daily (Low, 2000). Other physicians suggest between 3-5 grams of salt per day (Grubb et. al., 2006). Salt is 39% sodium, therefore 15 grams of salt equals 5,850 mg of sodium. Licorice root has been used as a remedy for various disorders throughout history. Itcan sometimes be used as an alternative to Florinef. Licorice root does have some side effects, and patients should get a physician's approval before taking it. Magnesium may be helpful to a number of POTS patients. Magnesium is sometimes prescribed to POTS patients with Ehlers-Danlos syndrome. Some patients report a decrease in arrhythmias after taking this mineral daily for a few weeks. Magnesium deficiency can cause many of the symptoms associated with POTS. Excessive norepinephrine levels can deplete magnesium levels. Magnesium should be used cautiously as it can lower blood pressure. Scheduling activities in the afternoon as opposed to the morning is a wise decision for those with POTS. Most patients report symptoms being greater in the morning hours. Sitting down in the shower instead of standing is helpful to many patients. It is important to avoid hot water as this will dilate blood vessels and exacerbate symptoms. Rinsing the legs (or whole body) in cold water before exiting the shower will constrict the blood vessels and should help one to feel less faint. A sock filled with warmed rice may provide some relief from the headaches that can accompany dysautonomia. Rice socks can be made by filling a tube sock with uncooked white rice, tying the sock closed at the end. Heat the rice filled sock in the microwave for a couple of minutes until warm. Be careful not to overheat, and be cautious of hot spots. The rice will hold heat and provide long-lasting relief of headaches. Standing up slowly will give a patient's body more time to adjust to upright posture. Patients getting up from a lying position may find it beneficial to sit up for a few minutes before standing. Treating allergies might help one to feel better. It has been reported that people with POTS lose their ability to vasoconstrict (Grubb, 2000). This means that many POTS patients have problems with their blood vessels being excessively dilated. Histamine is known to dilate blood vessels, which can further lower blood pressure in POTS patients. Allergies may also stimulate the sympathetic nervous system. Many POTS patients have overactive sympathetic nervous systems and benefit from avoiding potential sympathetic stimulants. Walking around right after getting out of bed is beneficial to some patients. The constricting leg muscles help to counteract pooling blood. Wearing ankle weights compels the leg muscles to work harder, thereby forcing pooling blood back into the upper body. It is especially helpful to put the weights on before getting out of bed in the morning. Ankle weights should not be worn continuously, as the body will then adjust to the extra weight and they will no longer be effective. Ankle weights should be used with caution, as they can possibly interfere with one's normal gait which can cause injury. It is important for one to consult a physician before trying any of the above treatments. Treatments that are beneficial to one patient may be detrimental to another. Do you know of something that may help POTS patients but is not listed here? Please send suggestions to: webmaster@dinet.org References 1. Gaffney, F. A., Lane, L. B., Pettinger, W., & Blomqvist C. G. (1983). Effects of long-term clonidine administration on the hemodynamic and neuroendocrine postural responses of patients with dysautonomia. Chest, 83(2 Suppl), 436-438. PMID: 6295714 [PubMed - indexed for MEDLINE] 2. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 3. Grubb, B. P. (2002, October). The heterogeneity of symptoms related to dysautonomia. Symposium conducted at the meeting of the National Dysautonomia Research Foundation Northwest Ohio Support Group. Toledo, Ohio. 4. Grubb, B. P., & Karas, B. J. (1998). The potential role of serotonin in the pathogenesis of neurocardiogenic syncope and related autonomic disturbances. Journal of Interventional Cardiac Electrophysiology, 2, 325-332. No abstract available. PMID: 10027117 [PubMed - indexed for MEDLINE] 5. Grubb, B.P., & Karas, B. (1999). Clinical disorders of the autonomic nervous system associated with orthostatic intolerance: an overview of classification, clinical evaluation, and management. Pacing and Clinical Electrophysiology. 22, 798-810. Full text: http://www.ndrf.org/PDF%20Files/disorders.PDF 6. Grubb, B.P., Kanjwal, Y., & Kosinski, D.J. (2006). The postural tachycardia syndrome: a concise guide to diagnosis and management. J Cardiovasc Electrophysiol, 17(1), 108-112. 7. Grubb, B.P., Kosinski, D., Mouhaffel, A., & Pothoulakis, A. (1996). The use of methylphenidate in the treatment of refractory neurocardiogenic syncope. Pace, 19, 836-840. PMID: 8734752 [PubMed - indexed for MEDLINE] 8. Grubb, B. P., & McMann, M. C. (2001) The Fainting Phenomenon: Understanding why people faint and what can be done about it. New York: Futura Publishing Company. 9. Hain, T. C., (2001). Orthostatic hypotension. Information about dizziness, ataxia and hearing disorders. (website no longer available) 10. Haran, C. (2004, January 30). Pressure Drop: Treating Orthostatic Hypotension [Interview with Dr. Blair P. Grubb]. Retrieved July 30, 2004 from Healtholgy. 11. Hilz, M. J., Marthol, H., Neundorfer, B. (2002). Syncope - a systematic overview of classification, pathogenesis, diagnosis and management. Fortschritte der Neurologie-Psychiatrie, 70, 95-107. PMID: 11823926 [PubMed - indexed for MEDLINE] 12. Hoeldtke, R. D., Bryner, K. D., Hoeldtke, M. E. & Hobbs G. (2007) Treatment of autonomic neuropathy, postural tachycardia and orthostatic syncope with octreotide LAR. Clin Auton Res. Aug., 31. PubMed 13. Hoeldtke, R. D., Horvath, G. G., & Bryner, K. D. (1995). Treatment of orthostatic tachycardia with erythropoietin. American Journal of Medicine, 99, 525-9. PMID: 7485211 [PubMed - indexed for MEDLINE] 14. Hoeldtke, R. D., & Streeten, D. H. P. (1993). Treatment of orthostatic hypotension with erythropoietin. The New England Journal of Medicine, 329, 611-615. PMID: 8341335 [PubMed - indexed for MEDLINE] 15. in t' Veld, B. A., Ruitenberg, A., Hofman, A., Launer, L. J., van Duijn, C. M., Stijnen, T., Breteler, M. M., & Stricker, B. H. (2001). Nonsteroidal antiinflammatory drugs and the risk of Alzheimer's disease. New England Journal of Medicine, 345, 1515-1521. PMID: 11794217 [PubMed - indexed for MEDLINE] 16. Jacob, G., & Biaggioni I. (1999). Idiopathic orthostatic intolerance and postural tachycardia syndromes. The American Journal of the Medical Sciences, 317, 88-101. PMID: 10037112 [PubMed - indexed for MEDLINE] 17. Jacob, G., Robertson, D., Mosqueda-Garcia, R., Ertl, A. C., Robertson, M. R., Biaggioni, I. (1997). Hypovolemia in syncope and orthostatic intolerance: role of the renin-angiotensin system. The American Journal of Medicine, 103, 128-133. PMID: 9274896 [PubMed - indexed for MEDLINE] 18. Jordan, J., Shannon, J.R., Grogan, E., Biaggioni, I., & Robertson, D. (1999). A potent pressor response elicited by drinking water. The Lancet, 353, 723. No abstract available. PMID: 10073520 [PubMed - indexed for MEDLINE] 19. Kadri, N. N., Hee, T. T., Rovang, K. S., Mohiuddin, S. M., Ryan, T., Ashraf, R., Huebert, V., & Hilleman, D. E. (1999). Efficacy and safety of clonazepam in refractory neurally mediated syncope. Pacing and Clinical Electrophysiology, 22, 307-314. PMID: 10087545 [PubMed - indexed for MEDLINE] 20. Low, P. A. (1994). Autonomic neuropathies. Current Opinion in Neurology, 7, 402-406. PMID: 7804460 [PubMed - indexed for MEDLINE] 21. Low, P. A. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 22. Low, P. A., Schondorf, R., Novak, V., Sandroni, P., Opfer-Gehrking, T. L., & Novak, P. (1997). Postural Tachycardia Syndrome. In P.A. Low (Ed.), Clinical Autonomic Disorders (pp. 681-697). Philadelphia: Lippincott-Raven Publishers. 23. Mathias, C. J. (2000, July). Other autonomic disorders. National Dysautonomia Research Foundation Patient conference. Minneapolis, Minnesota. 24. Mathias, C. J. (2003). Autonomic diseases: management. Journal of Neurology, Neurosurgery & Psychiatry. 74 Suppl 3:iii, 42-47. Full Text: http://jnnp.bmjjournals.com/cgi/content/full/74/suppl_3/iii42 25. Raj, S. R., Biaggioni, I., Yamhure, P. C., Black, B. K., Paranjape, S. Y., Byrne, D. W., & Robertson, D. (2005). Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Circulation. 111(13), 1574-1582. 26. Redman, D. A. (2000). Ruscus aculeatus (butcher's broom) as a potential treatment for orthostatic hypotension, with a case report. The Journal of Alternative and Complementary Medicine. 6, 539-549. PMID: 11152059 [PubMed - indexed for MEDLINE] 27. Schondorf, R., & Freeman, R. (1999). The importance of orthostatic intolerance in the chronic fatigue syndrome. American Journal of the Medical Sciences, 317, 117-123. http://www.ncf-net.org/library/orthostaticreview.htm 28. Shannon, J. R., Diedrich, A., Biaggioni, I., Tank, J., Robertson, R. M., Robertson, D., & Jordan, J. (2002). Water drinking as a treatment for orthostatic syndromes. American Journal of Medicine, 112, 355-60. PMID: 11904109 [PubMed - indexed for MEDLINE] 29. Shibao C, Arzubiaga C, Roberts LJ 2nd, Raj S, Black B, Harris P, Biaggioni I. (2005). Hyperadrenergic postural tachycardia syndrome in mast cell activation disorders. Hypertension, 45(3), 385-390. Full text: http://hyper.ahajournals.org/cgi/content/full/45/3/385 30. Shores, M. M., Pascualy, M., Lewis, N. L., Flatness, D., & Veith, R. C. (2001). Short-term sertraline treatment suppresses sympathetic nervous system activity in healthy human subjects. Psychoneuroendocrinology, 26, 433-439. PMID: 11259862 [PubMed - indexed for MEDLINE] 31. Streeten, D. H. (1999). Orthostatic intolerance. A historical introduction to the pathophysiological mechanisms. The American Journal of the Medical Sciences, 317, 78-87. PMID: 10037111. 32. van Lieshout JJ., Pott, F., Madsen, P. L., van Goudoever, J., Secher, N. H. (2001). Muscle tensing during standing: effects on cerebral tissue oxygenation and cerebral artery blood velocity. Stroke, 32, 1546- 1551. Full text: http://stroke.ahajournals.org/cgi/content/full/32/7/1546 33. Vanderbilt University Autonomic Dysfunction Center. (1999). Orthostatic Intolerance. Retrieved May 4, 2004, from the World Wide Web. http://www.mc.vanderbilt.edu/root/vumc.php?site=adc&doc=4788 34. Drugs & Medications: Medscape, Northera http://www.webmd.com/drugs/2/drug-166782/northera-oral/details

The contents of this Web page are provided for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis or treatment. Please keep in mind that new treatments are continually emerging and some of the older treatments may rarely be used. Your physician may prescribe medication to decrease the symptoms of POTS. Doctors admit that treatment can be a challenge and that no single therapy is uniformly successful. Medications that are useful in some patients may have no effect in others (Jacob & Biaggioni, 1999). Occasionally medications can worsen symptoms. Medications used to treat POTS include the following: Anti-arrhythmic drugs, such as disopyramide (norpace), have been used to treat POTS patients. However, studies have shown that some anti-arrhythmic drugs may increase the risk of death, and they are usually used only to treat life-threatening arrhythmias. Benzodiazepines, such as Clonazepam (klonopin) or alprazolam (xanax), are not used as a first-line of treatment and can worsen tachycardia and hypotension. However, they may be helpful in select patients. Klonapin has been shown to be effective in the treatment of some patients with neurally mediated syncope (Kadri, Hee, Rovang, Mohiuddin, Ryan, Ashraf, Huebert & Hilleman, 1999). These drugs are central nervous system depressants. They are thought to enhance the effect of gaba, an inhibitory neurotransmitter. Benzodiazepines should be used with caution, as they are highly addictive. Some physicians do not advocate their use. Beta Blockers are especially useful in those with elevated norepinephrine levels, beta-receptor supersensitivity and a hyperadrenergic state. Beta blockers can exacerbate hypotension and are not well tolerated by some dysautonomics. Beta blockers need to be used with caution, as they are known to reduce plasma renin activity. Research shows that hypovolemic orthostatic intolerant patients commonly have inappropriately low levels of plasma renin activity (Jacob, Robertson, Mosqueda-Garcia, Ertl, Robertson & Biaggioni, 1997). Reduced plasma renin activity may be an important pathophysiologic component of the syndrome of orthostatic intolerance (Jacob et al., 1997). Hence, some POTS patients may have low plasma renin activity that is contributing to their disorder. Beta blockers may further lower plasma renin activity in these patients. Therefore, the use of beta blockers in some hypovolemic patients may be counterproductive. Beta blockers should be used with caution, if at all, in those with mast-cell activation disorders (Shibao, Arzubiaga, Roberts, Raj, Black, Harris & Biaggioni, 2005). Beta blockers may trigger mast-cell activation. Cerefolin is a vitamin supplement that may help patients combat fatigue and feel more alert. Clonidine (Catepres) is a centrally acting alpha-agonist agent. Clonidine inhibits sympathetic outflow (Grubb & McMann, 2001, p. 117). It can stabilize heart rate and blood pressure in patients with post-ganglionic sympathetic involvement (Gaffney, Lane, Pettinger & Blomqvist, 1983). Clonidine will actually display a vasoconstrictive effect in these patients. Clonidine is started at 0.1 mg a day and titrated upward (Grubb, Kanjwal & Kosinski, 2006). It is available in a long-acting patch form. DDAVP (Desmopressin) is used to help patients retain water. DDAVP can raise blood pressure and seems to be especially useful in lessening morning hypotension. It is a man made copy of the anti-diuretic hormone vassopressin. Vassopressin and DDAVP stimulate the kidneys to concentrate urine. Droxidopa (Northera) Droxidopa, a norepinephrine (NE) precursor, improves symptoms of neurogenic orthostatic hypotension (nOH) by replenishing NE levels. Central NE effects are poorly described but may offer potential benefits given the pathophysiologic progression of alpha-synuclein related disorders. Erythropoietin raises blood pressure and red cell mass. Red blood cell volume has been found to be low in POTS patients (Raj, Biaggioni, Yamhure, Black, Paranjape, Byrne & Robertson, 2005). Erythropoietin is also a potent vasoconstrictor and is quite useful in the treatment of orthostatic disorders (Grubb, Kanjwal & Kosinski, 2006). There may be an impairment in erythropoietin production and/or function in some individuals with POTS. Erythropoietin reportedly works in 80% of patients (Grubb, 2002). One study showed that erythropoietin administration led to dramatic improvements in some patients with orthostatic hypotension (Hoeldtke & Streeten, 1993). However, a later study of (only) 8 patients with orthostatic tachycardia reported that erythropoietin did not help the tachycardia (Hoeldtke, Horvath & Bryner, 1995). Erythropoietin is not commonly used because it has to be injected and is expensive. Procrit is a common medication that increases erythropoietin, which in turn increases red blood cell mass. Patients treated with erythropoietin may need iron supplementation as their hematocrit rises. Prior to starting erythropoietin, a complete serum blood count (CBC) as well as a serum iron, total iron binding capacity, and ferritin level should be obtained by one's physician (Grubb, Kanjwal & Kosinski, 2006). Erythropoietin can be employed as long as the hematocrit (HCT) is less than 50, and patients appear to achieve the best hemodynamic effect when the HCT is in the low to mid-40 range. The usual starting dose of erythropoietin is 10,000 units injected subcutaneously once weekly, and it usually takes 4-6 weeks to see the full effects of this medication (Grubb, Kanjwal & Kosinski, 2006). Patients should have their HCT checked monthly to make sure it is below 50. Florinef (Fludrocortisone) increases plasma volume. It helps the body to retain salt and water. It also sensitizes blood vessels so that they can constrict more easily (Haran, 2004). Some doctors administer salt tablets with florinef. This is because the effectiveness of Florinef depends upon salt intake. Florinef can deplete potassium and magnesium and supplements may be required. Florinef increases intracranial pressure and should not be used in patients with hind brain compression. Numerous symptoms of sympathetic overactivity are enhanced by Florinef and some people develop severe headaches as a result of treatment (Schondorf & Freeman, 1999). Florinef is a mineralocorticoid and, like beta blockers, can reduce levels of plasma renin activity (Jacob et al., 1997). Reduced levels of plasma renin activity correlate with the hypovolemia observed in some POTS patients. Florinef may be a counterproductive treatment in these patients. Usually, POTS patients are prescribed 0.1-0.2 mg of fludrocortisone daily. The dose should never exceed 0.4 mg orally each day as adrenal suppression may occur (Grubb, Kanjwal & Kosinski, 2006). Ivabradine, a sinus node blocker, has reportedly helped some POTS patients experience less symptoms. Ivabradine is sometimes used as an alternative to beta-blockers because it results in heart rate reduction without vasodilation, sexual disturbances, ornegative inotropic effects. Labetalol is sometimes used in POTS patients because it induces both alpha- and beta-blockade. Dosages of 100-400 mg orally twice a day may be employed (Grubb, Kanjwal & Kosinski, 2006). Carvedilol works in a similar fashion to labetalol and is also sometimes employed as a treatment for POTS. Methyldopa is helpful in select POTS patients (Grubb, Kanjwal & Kosinski, 2006). Mestinon (Pyridostigmine Bromide) has traditionally been used to treat myasthenia gravis, but is now sometimes being used to treat POTS patients (Grubb, 2002). Mestinon works by inhibiting the breakdown of acetylcholine. Acetylcholine is the main chemical messenger of the parasympathetic nervous system. Some POTS patients may have immune systems that are mistakenly making antibodies that are plugging up acetylcholine receptors (Grubb, 2002). Mestinon works to unplug these receptors by allowing more acetylcholine to remain at the neuromuscular junction. Mestinon is particulary useful in patients who have the postviral, paraneoplastic or autoimmune forms of POTS. Mestinon is usually started at 30 mg orally twice a day, titrating to 60 mg orally twice daily, if necessary (Grubb, Kanjwal & Kosinski, 2006). Motrin (Ibuprofen) or Indocin (Indomethacin) might be beneficial treatments for patients with postprandial hypotension (Hilz, Marthol & Neundorfer, 2002). Postprandial hypotension refers to low blood pressure occurring after meals. Motrin and indocin block the blood pressure lowering effects of prostaglandins (Hain, 2001). Studies have suggested that nonsteroidal anti-inflammatory drugs may also lower one's risk of developing Alzheimer's disease(in t' Veld, Ruitenberg, Hofman, Launer, van Duijn, Stijnen, Breteler & Stricker, 2001). However, long term use of nonsteroidal anti-inflammatory drugs can have serious side effects. Phenobarbital is a central nervous system depressant. It can be useful in the hyperadrenergic form of dysautonomia. However, phenobarbital is a barbiturate and people can become addicted to this drug. Barbiturates can also cause fainting (Grubb & McMann, 2001, p. 109). Prednisone, plasma exchange or intravenous gamma globulin may be used in patients who are in the acute post-viral phase of the illness (Low, Schondorf, Novak, Sandroni, Opfer-Gehrking & Novak, 1997, p. 694). These treatments are most likely to be effective in patients displaying evidence of an acute autonomic neuropathy. Saline has shown to be very beneficial in decreasing POTS symptoms. It is an inexpensive treatment with few side effects. However, saline must be given through an IV, which is time consuming and may require trips to the doctor's office. Some of the most severely affected patients report having a peripherally inserted central catheter (PICC line) inserted so that IVs can be administered at home. However, some physicians do not believe the benefits outweigh the possible risks associated with a PICC line. Selective Serotonin Reuptake Inhibitors (SSRI's) are sometimes used to treat those with autonomic disorders. SSRI's are used because serotonin is the principal neurotransmitter that the brain uses to govern autonomic control, in particular to govern blood pressure (Haran, 2004). Studies have shown that some patients with autonomic disorders may have disturbances in central serotonin production and regulation (Grubb & Karas, 1998). SSRI treatment can suppress the sympathetic nervous system (Shores, Pascualy, Lewis, Flatness & Veith, 2001). Venlafaxine is particularly effective, possibly due to its actions on norepinephrine as well as serotonin. It has been reported that SSRI's may be effective in treating the chest pain that is associated with dysautonomia (Low, 2000). However, the FDA has issued a public health advisory regarding antidepressants, and they should be used with caution. Sleep medications are used by some POTS patients. A number of patients have significant sleep disturbances (Low, 2000). Some patients report successfully using natural alternatives to sleep medication. Herbal remedies should be used with caution and under a physician's supervision, as there are known risks with some OTC sleep aids. For example, the FDA has issued warnings regarding Kava Kava and melatonin supplements have been shown to worsen orthostatic intolerance. Stopping menstruation through the use of birth control pills has reportedly helped some patients feel better. Many women report a worsening of symptoms around menstruation. Stopping menstruation is somewhat controversial, and not all physicians advocate it. Vasoconstrictors such as ergotamine, midodrine, octreotide, ephedrine, pseudoephedrine, yohimbine, theophylline and ritalin improve venous tone which decreases pooling blood. Midodrine is particularly useful in patients with peripheral denervation (Low, 2000). Midodrine is usually started at 5 mg orally three times a day and can be titrated up to 15-20 mg orally four times a day, if necessary (Grubb, Kanjwal & Kosinski, 2006). Midodrine can be used on an as needed basis. Theoretically, continuous use of midodrine could result in constriction of blood volume due to chronic sympathetic activation (Jacob & Biaggioni, 1999). Octreotide is especially useful in preventing vasodilation in the gut, thereby reducing splanchnic pooling. Its actions help to prevent postprandial hypotension (low blood pressure after meals). Octreotide inhibits the release of a variety of gastrointestinal peptides and also may reduce postural and exercise induced hypotension (Mathias, 2003). Octreotide does not often appear to enhance supine nocturnal hypertension, however one study reports that it is a possible side effect (Hoeldtke, Bryner, Hoeldtke & Hobbs, 2007). Octreotide is administered by subcutaneous injection starting at 50 µg 2-3 times a day, and dosages may be titrated up to 100-200 µg three times a day (Grubb, Kanjwal & Kosinski, 2006). A long-acting injectable form has also been developed. Ephedrine is not often used due to its short half-life and undesirable B-adrenergic actions (Jacob & Biaggioni, 1999). Ephedrine can cause tachycardia. Theophyllineis primarily used in asthma patients. One of its effects is to increase vasoconstriction, therefore theophylline is sometimes used to treat dysautonomia (Grubb & McMann, 2001, p. 116). Ritalin increases peripheral vascular resistance via alpha receptor stimulation (Grubb, Kosinski, Mouhaffel & Pothoulakis, 1996). Ritalin is prescribed by some physicians, but can be addictive. Wellbutrin (Bupropion) is a central nervous system stimulant. It is a dopamine agonist and also a weak blocker of the neuronal uptake of serotonin and norepinephrine. Wellbutrin is not habit forming and works immediately. Wellbutrin can sometimes be used to combat the fatigue that plagues POTS patients. There are also many non-pharmaceutical methods to decrease the symptoms of POTS. These include the following: Butcher's broom may lessen orthostatic hypotension in some patients (Redman, 2000). Studies show that butcher's broom does not cause supine hypertension and that it can alleviate the worsening of symptoms in hot environments. Butcher's broom is a vasoconstrictor that reduces capillary permeability. Butcher's broom has been used as a diuretic, so patient's need to be especially cautious about taking it. Butcher's broom should only be taken under a doctor's supervision. Changing eating habits and diet can help relieve hypotension. Patients should eat frequent small meals instead of three large meals a day. This will help reduce the amount of blood needed for digestion. Hence, more blood will be available for the brain and heart. Refined carbohydrates, such as white flour and sugar, can exacerbate hypotension (Mathias, 2000). There are patients that report a worsening of symptoms when eating certain foods, such as dairy products. It is important for each patient to identify and avoid their food triggers. Cooling devices can help POTS patients. Cool Sport* sells personal body cooling vests that may help patients tolerate hot environments. Countermaneuvers can help to decrease symptoms by lessening the amount of blood that pools in one's legs. Useful countermaneuvers include: standing with your legs crossed, sitting in a low chair, sitting in the knee to chest position, leaning forward with your hands on your knees when sitting and tightening the buttocks, thigh and leg muscles when standing (particularly when standing for any length of time). Research shows that tensing the leg muscles while standing enhances brain blood flow and reduces sympathetic activity (van Lieshout Pott, Madsen, van Goudoever & Secher, 2001.) Squatting can also be a useful countermaneuver, although some patients report an increase in symptoms after squatting. Compression devices, such as abdominal binders and compression stockings, help to reduce the amount of pooling blood. Compression stockings should be at least 30-40 mm Hg and will work best if they are waist high (Grubb & Karas, 1999). Compression stockings should be fitted to achieve the greatest benefit. BrightLife Direct* carries affordable compression hosiery. One POTS patient has found relief of symptoms by wearing a G-suit, and she has created a website that details her experience with this compression device. Her website begins "G-suits are pants that can save the life of a fighter pilot. G-suits are pants that have 'saved' my life too." Click here to visit this patient's informative website. Correcting anemia has been shown to improve orthostatic tolerance (Low, 1994). Elevating the head of the bed 4-12 inches has helped some POTS patients become less symptomatic. It has been reported that elevating the head of the bed generates mechanisms that expand plasma volume (Low, 2000). Exercise can be helpful to those with dysautonomia. It is important that one does not let their body become deconditioned, as this will exacerbate symptoms. Tightening and building the leg muscles will help them to squeeze pooling blood back to the upper part of the body. Swimming in water has been reported to help many dysautonomics, however no one who faints should go into water alone. Yaz Exercises and recumbent stationary bikes may be beneficial to some patients with POTS. Aerobic exercise performed for 20 minutes a day, three times a week, is sometimes recommended for patients who can tolerate it (Grubb, Kanjwal & Kosinski, 2006). Getting plenty of rest is very important for those with POTS. It has been reported that some POTS patients have significant sleep disturbances (Low, 2000). These patients may require more sleep than the average person. Heart rate watches can help patients identify situations that trigger heart rate increases. These watches are available at sports stores or can be purchased on the Internet. Ice has reportedly helped some POTS patients. Rubbing ice on the body, especially on the bottom of the feet or neck, may help some POTS patients ward off an episode. Increasing fluids helps many people with POTS to feel better. Many POTS patients report Gatorade or electrolyte solutions to be particularly helpful. Drinking water has been shown to moderately reduce orthostatic tachycardia in patients with idiopathic orthostatic intolerance (Shannon, Diedrich, Biaggioni, Tank, Robertson, Robertson & Jordan, 2002). Drinking large amounts of water helps to raise blood pressure (Jordan, Shannon, Grogan, Biaggioni & Robertson, 1999). Consuming large amounts of water increases blood volume, which is especially useful in the hypovolemic and those with pooling blood. Some patients report that drinking water before getting out of bed in the morning helps decrease symptoms. Physicians suggest patients drink eight eight-ounce glasses of water daily (Low, 2000). Patients should not drink excessive amounts of water because doing so can cause essential electrolytes to become diluted in the bloodstream, which may affect heart rhythm. Increasing salt is a treatment used for many people with POTS, however salt is not recommended for all patients. While normal subjects reduce urinary sodium excretion on assumption of upright posture, patients with orthostatic intolerance do so ineffectively (Vanderbilt University Autonomic Dysfunction Center, 1999). Impaired renal sodium conservation can contribute to hypovolemia (Streeten, 1999). One study found POTS patients to have inappropriately low levels of renin and aldosterone, two hormones that promote sodium retention and increase plasma volume (Raj, Biaggioni, Yamhure, Black, Paranjape, Byrne & Robertson, 2005). Renin and aldosterone are both regulated by the kidney. Increasing salt is an effective way to raise blood pressure in many patients with orthostatic hypotension. Salt helps to expand blood volume. A number of patients find salt tablets and/or electrolyte solutions to be helpful. Some physicians suggest patients who benefit from salt take in 10-15 grams daily (Low, 2000). Other physicians suggest between 3-5 grams of salt per day (Grubb et. al., 2006). Salt is 39% sodium, therefore 15 grams of salt equals 5,850 mg of sodium. Licorice root has been used as a remedy for various disorders throughout history. Itcan sometimes be used as an alternative to Florinef. Licorice root does have some side effects, and patients should get a physician's approval before taking it. Magnesium may be helpful to a number of POTS patients. Magnesium is sometimes prescribed to POTS patients with Ehlers-Danlos syndrome. Some patients report a decrease in arrhythmias after taking this mineral daily for a few weeks. Magnesium deficiency can cause many of the symptoms associated with POTS. Excessive norepinephrine levels can deplete magnesium levels. Magnesium should be used cautiously as it can lower blood pressure. Read more Scheduling activities in the afternoon as opposed to the morning is a wise decision for those with POTS. Most patients report symptoms being greater in the morning hours. Sitting down in the shower instead of standing is helpful to many patients. It is important to avoid hot water as this will dilate blood vessels and exacerbate symptoms. Rinsing the legs (or whole body) in cold water before exiting the shower will constrict the blood vessels and should help one to feel less faint. A sock filled with warmed rice may provide some relief from the headaches that can accompany dysautonomia. Rice socks can be made by filling a tube sock with uncooked white rice, tying the sock closed at the end. Heat the rice filled sock in the microwave for a couple of minutes until warm. Be careful not to overheat, and be cautious of hot spots. The rice will hold heat and provide long-lasting relief of headaches. Standing up slowly will give a patient's body more time to adjust to upright posture. Patients getting up from a lying position may find it beneficial to sit up for a few minutes before standing. Treating allergies might help one to feel better. It has been reported that people with POTS lose their ability to vasoconstrict (Grubb, 2000). This means that many POTS patients have problems with their blood vessels being excessively dilated. Histamine is known to dilate blood vessels, which can further lower blood pressure in POTS patients. Allergies may also stimulate the sympathetic nervous system. Many POTS patients have overactive sympathetic nervous systems and benefit from avoiding potential sympathetic stimulants. Walking around right after getting out of bed is beneficial to some patients. The constricting leg muscles help to counteract pooling blood. Wearing ankle weights compels the leg muscles to work harder, thereby forcing pooling blood back into the upper body. It is especially helpful to put the weights on before getting out of bed in the morning. Ankle weights should not be worn continuously, as the body will then adjust to the extra weight and they will no longer be effective. Ankle weights should be used with caution, as they can possibly interfere with one's normal gait which can cause injury. It is important for one to consult a physician before trying any of the above treatments. Treatments that are beneficial to one patient may be detrimental to another. Do you know of something that may help POTS patients but is not listed here? Please send suggestions to: Dysautonomia Information Network *The Dysautonomia Information Network is in no way affiliated with Cool Sport or BrightLife direct and is not promoting their products. References 1. Gaffney, F. A., Lane, L. B., Pettinger, W., & Blomqvist C. G. (1983). Effects of long-term clonidine administration on the hemodynamic and neuroendocrine postural responses of patients with dysautonomia. Chest, 83(2 Suppl), 436-438. PMID: 6295714 [PubMed - indexed for MEDLINE] 2. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 3. Grubb, B. P. (2002, October). The heterogeneity of symptoms related to dysautonomia. Symposium conducted at the meeting of the National Dysautonomia Research Foundation Northwest Ohio Support Group. Toledo, Ohio. 4. Grubb, B. P., & Karas, B. J. (1998). The potential role of serotonin in the pathogenesis of neurocardiogenic syncope and related autonomic disturbances. Journal of Interventional Cardiac Electrophysiology, 2, 325-332. No abstract available. PMID: 10027117 [PubMed - indexed for MEDLINE] 5. Grubb, B.P., & Karas, B. (1999). Clinical disorders of the autonomic nervous system associated with orthostatic intolerance: an overview of classification, clinical evaluation, and management. Pacing and Clinical Electrophysiology. 22, 798-810. Full text: http://www.ndrf.org/PDF%20Files/disorders.PDF 6. Grubb, B.P., Kanjwal, Y., & Kosinski, D.J. (2006). The postural tachycardia syndrome: a concise guide to diagnosis and management. J Cardiovasc Electrophysiol, 17(1), 108-112. 7. Grubb, B.P., Kosinski, D., Mouhaffel, A., & Pothoulakis, A. (1996). The use of methylphenidate in the treatment of refractory neurocardiogenic syncope. Pace, 19, 836-840. PMID: 8734752 [PubMed - indexed for MEDLINE] 8. Grubb, B. P., & McMann, M. C. (2001) The Fainting Phenomenon: Understanding why people faint and what can be done about it. New York: Futura Publishing Company. 9. Hain, T. C., (2001). Orthostatic hypotension. Information about dizziness, ataxia and hearing disorders. (website no longer available) 10. Haran, C. (2004, January 30). Pressure Drop: Treating Orthostatic Hypotension [Interview with Dr. Blair P. Grubb]. Retrieved July 30, 2004 from Healtholgy. 11. Hilz, M. J., Marthol, H., Neundorfer, B. (2002). Syncope - a systematic overview of classification, pathogenesis, diagnosis and management. Fortschritte der Neurologie-Psychiatrie, 70, 95-107. PMID: 11823926 [PubMed - indexed for MEDLINE] 12. Hoeldtke, R. D., Bryner, K. D., Hoeldtke, M. E. & Hobbs G. (2007) Treatment of autonomic neuropathy, postural tachycardia and orthostatic syncope with octreotide LAR. Clin Auton Res. Aug., 31. PubMed 13. Hoeldtke, R. D., Horvath, G. G., & Bryner, K. D. (1995). Treatment of orthostatic tachycardia with erythropoietin. American Journal of Medicine, 99, 525-9. PMID: 7485211 [PubMed - indexed for MEDLINE] 14. Hoeldtke, R. D., & Streeten, D. H. P. (1993). Treatment of orthostatic hypotension with erythropoietin. The New England Journal of Medicine, 329, 611-615. PMID: 8341335 [PubMed - indexed for MEDLINE] 15. in t' Veld, B. A., Ruitenberg, A., Hofman, A., Launer, L. J., van Duijn, C. M., Stijnen, T., Breteler, M. M., & Stricker, B. H. (2001). Nonsteroidal antiinflammatory drugs and the risk of Alzheimer's disease. New England Journal of Medicine, 345, 1515-1521. PMID: 11794217 [PubMed - indexed for MEDLINE] 16. Jacob, G., & Biaggioni I. (1999). Idiopathic orthostatic intolerance and postural tachycardia syndromes. The American Journal of the Medical Sciences, 317, 88-101. PMID: 10037112 [PubMed - indexed for MEDLINE] 17. Jacob, G., Robertson, D., Mosqueda-Garcia, R., Ertl, A. C., Robertson, M. R., Biaggioni, I. (1997). Hypovolemia in syncope and orthostatic intolerance: role of the renin-angiotensin system. The American Journal of Medicine, 103, 128-133. PMID: 9274896 [PubMed - indexed for MEDLINE] 18. Jordan, J., Shannon, J.R., Grogan, E., Biaggioni, I., & Robertson, D. (1999). A potent pressor response elicited by drinking water. The Lancet, 353, 723. No abstract available. PMID: 10073520 [PubMed - indexed for MEDLINE] 19. Kadri, N. N., Hee, T. T., Rovang, K. S., Mohiuddin, S. M., Ryan, T., Ashraf, R., Huebert, V., & Hilleman, D. E. (1999). Efficacy and safety of clonazepam in refractory neurally mediated syncope. Pacing and Clinical Electrophysiology, 22, 307-314. PMID: 10087545 [PubMed - indexed for MEDLINE] 20. Low, P. A. (1994). Autonomic neuropathies. Current Opinion in Neurology, 7, 402-406. PMID: 7804460 [PubMed - indexed for MEDLINE] 21. Low, P. A. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 22. Low, P. A., Schondorf, R., Novak, V., Sandroni, P., Opfer-Gehrking, T. L., & Novak, P. (1997). Postural Tachycardia Syndrome. In P.A. Low (Ed.), Clinical Autonomic Disorders (pp. 681-697). Philadelphia: Lippincott-Raven Publishers. 23. Mathias, C. J. (2000, July). Other autonomic disorders. National Dysautonomia Research Foundation Patient conference. Minneapolis, Minnesota. 24. Mathias, C. J. (2003). Autonomic diseases: management. Journal of Neurology, Neurosurgery & Psychiatry. 74 Suppl 3:iii, 42-47. Full Text: http://jnnp.bmjjournals.com/cgi/content/full/74/suppl_3/iii42 25. Raj, S. R., Biaggioni, I., Yamhure, P. C., Black, B. K., Paranjape, S. Y., Byrne, D. W., & Robertson, D. (2005). Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Circulation. 111(13), 1574-1582. 26. Redman, D. A. (2000). Ruscus aculeatus (butcher's broom) as a potential treatment for orthostatic hypotension, with a case report. The Journal of Alternative and Complementary Medicine. 6, 539-549. PMID: 11152059 [PubMed - indexed for MEDLINE] 27. Schondorf, R., & Freeman, R. (1999). The importance of orthostatic intolerance in the chronic fatigue syndrome. American Journal of the Medical Sciences, 317, 117-123. http://www.ncf-net.org/library/orthostaticreview.htm 28. Shannon, J. R., Diedrich, A., Biaggioni, I., Tank, J., Robertson, R. M., Robertson, D., & Jordan, J. (2002). Water drinking as a treatment for orthostatic syndromes. American Journal of Medicine, 112, 355-60. PMID: 11904109 [PubMed - indexed for MEDLINE] 29. Shibao C, Arzubiaga C, Roberts LJ 2nd, Raj S, Black B, Harris P, Biaggioni I. (2005). Hyperadrenergic postural tachycardia syndrome in mast cell activation disorders. Hypertension, 45(3), 385-390. Full text: http://hyper.ahajournals.org/cgi/content/full/45/3/385 30. Shores, M. M., Pascualy, M., Lewis, N. L., Flatness, D., & Veith, R. C. (2001). Short-term sertraline treatment suppresses sympathetic nervous system activity in healthy human subjects. Psychoneuroendocrinology, 26, 433-439. PMID: 11259862 [PubMed - indexed for MEDLINE] 31. Streeten, D. H. (1999). Orthostatic intolerance. A historical introduction to the pathophysiological mechanisms. The American Journal of the Medical Sciences, 317, 78-87. PMID: 10037111. 32. van Lieshout JJ., Pott, F., Madsen, P. L., van Goudoever, J., Secher, N. H. (2001). Muscle tensing during standing: effects on cerebral tissue oxygenation and cerebral artery blood velocity. Stroke, 32, 1546- 1551. Full text: http://stroke.ahajournals.org/cgi/content/full/32/7/1546 33. Vanderbilt University Autonomic Dysfunction Center. (1999). Orthostatic Intolerance. Retrieved May 4, 2004, from the World Wide Web. http://www.mc.vanderbilt.edu/root/vumc.php?site=adc&doc=4788 34. Drugs & Medications: Medscape, Northera http://www.webmd.com/drugs/2/drug-166782/northera-oral/details

POTS is a disorder that can easily be overlooked or misdiagnosed. Some patients have had to wait years before their condition was properly labeled. POTS is sometimes misdiagnosed because of the wide array of symptoms that accompany this syndrome. The symptoms of postural orthostatic tachycardia often mimic other illnesses. Entities such as thyroid disease, pheochromocytoma, hypoadrenalism, cardiac disease, autonomic neuropathies, medication side effects and anxiety disorders need to be ruled out before a patient is labeled with POTS (Low, 2000). POTS is an easy disorder to overlook because physicians routinely take heart and blood pressure readings while the patient is sitting down. The POTS patient may have relatively normal vital signs while sitting down. Also, POTS symptoms can vary from day to day. Patients sometimes report good phases in which their symptoms are milder, followed by bad phases in which symptoms become more severe. This fluctuation in symptoms can also lead to difficulties in detecting POTS. Physicians that have experience in detecting and treating dysautonomia can be located on our Find a Physician database of dysautonomia specialists. There are a variety of tests that the POTS patient may undergo. Orthostatic symptoms are usually the most debilitating aspect of autonomic dysfunction readily amenable to therapy, and for this reason the blood pressure and heart rate response to upright posture should be the starting point of any autonomic laboratory evaluation (Robertson, 1996, p. 111). To learn about the tests used to diagnose POTS and other forms of dysautonomia, please visit our Autonomic Testing page.

POTS is a disorder that can easily be overlooked or misdiagnosed. Some patients have had to wait years before their condition was properly labeled. POTS is sometimes misdiagnosed because of the wide array of symptoms that accompany this syndrome. The symptoms of postural orthostatic tachycardia often mimic other illnesses. Entities such as thyroid disease, pheochromocytoma, hypoadrenalism, cardiac disease, autonomic neuropathies, medication side effects and anxiety disorders need to be ruled out before a patient is labeled with POTS (Low, 2000). POTS is an easy disorder to overlook because physicians routinely take heart and blood pressure readings while the patient is sitting down. The POTS patient may have relatively normal vital signs while sitting down. Also, POTS symptoms can vary from day to day. Patients sometimes report good phases in which their symptoms are milder, followed by bad phases in which symptoms become more severe. This fluctuation in symptoms can also lead to difficulties in detecting POTS. Physicians that have experience in detecting and treating dysautonomia can be located on our Find a Physician database of dysautonomia specialists. There are a variety of tests that the POTS patient may undergo. Orthostatic symptoms are usually the most debilitating aspect of autonomic dysfunction readily amenable to therapy, and for this reason the blood pressure and heart rate response to upright posture should be the starting point of any autonomic laboratory evaluation (Robertson, 1996, p. 111). To learn about the tests used to diagnose POTS and other forms of dysautonomia, please visit our Autonomic Testing page.

POTS symptoms can occur due to many different abnormalities in the body. Some disorders associated with POTS symptoms have been identified. Many of the causes of POTS still remain unknown. It can be difficult to distinguish between the causes and effects of this disorder, which further complicates matters. There are a multitude of disorders that can produce POTS-like symptoms. It is important that physicians attempt to find possible causes of a patient's orthostatic intolerance, as many secondary disorders are treatable. Some of the entities that may be contributing to one's orthostatic intolerance include: Adrenal disorders, such as Addison's disease,can produce symptoms that mimic POTS. Anemia patients sometimes exhibit the symptoms of POTS (Nand, Mohan, Khosla & Kumar, 1989). Some patients may have folic acid deficiency, which is contributing to their anemia and POTS symptoms. POTS patients may have a form of hidden anemia where the standard tests, such as hemoglobin and hematocrit, are relatively normal even though the patient has a severe anemia (Raj, Biaggioni, Yamhure, Black, Paranjape, Byrne & Robertson, 2005). A formal radioisotope dilution assessment of blood volumes was required to discover the red blood cell volume deficit documented in a 2005 study of POTS patients (Raj, et. al, 2005). The authors of this study state that it is possible a deficit in erythropoietin production might play a pathophysiological role in POTS, although this is not yet clear. Angiotensin II has been found to be increased in some people with postural orthostatic tachycardia syndrome. The results from one study imply impaired catabolism of Angiotensin II through the angiotensin-converting enzyme 2 pathway. Vasoconstriction in POTS may result from a reduction in Ang-(1-7) and an increase in angiotensin II (Stewart, Ocon, Clarke, Taneja & Medow, 2009). The angiotensin II type I receptor gene may be responsible for some orthostatic disorders.The NIH has researched vascular responsiveness in subjects with polymorphisms of the angiotensin II type I receptor gene. Angiotensin II is a hormone that constricts blood vessels by attaching to a protein on the blood vessels. People can have a variety of forms of this protein. Researchers have looked for differences in the gene that makes this protein to determine if these genetic differences have any effect on blood pressure. Autoimmune disorders,such as Guillain-Barre (NIH.gov) and lupus are suspected of causing POTS symptoms in some individuals. Researchers have discovered an antibody to neuronal nicotinic acetylcholine receptors of autonomic ganglia (Vernino, Low, Fealey, Stewart, Farrugia & Lennon, 2000). Some people with POTS have an antibody titer test that is positive to this antibody. Patients with orthostatic intolerance, anhidrosis, constipation, urinary dysfunction, sjogrens syndrome and pupillary dysfunction had higher antibody titers than subjects that did not (Gibbons & Freeman, 2009). Patients with the highest levels of these ganglionic-receptor-binding antibodies have the most severe autonomic dysfunction. Physicians have discovered that antibody levels lower as some patients improve, which suggests a cause and effect relationship. Patients interested in being tested for the ganglionic antibody should have their physician contact: Mayo Clinic Laboratories 1-800-533-1710 mcl@mayo.edu Cardiac atrophy has been pinpointed as the cause of orthostatic intolerance in astronauts. Research has shown that astronauts' hearts actually shrink and stiffen due to the reduced blood volume caused by microgravity (Mitka, 2002). Researchers want to find out if the cardiac atrophy is entirely reversible, and if the loss of mass can reach a point where it leads to catastrophic consequences (Healthline Scripts: Cardiac Atrophy, 1998). This finding may have implications for people who develop orthostatic intolerance due to being bedridden. Whether or not the finding can be applied to a percentage of patients who develop orthostatic intolerance for other reasons has yet to be proven. Cardiac disease can cause POTS symptoms. Most physicians are quick to rule cardiac disease out. Cardiac electrophysiologic property abnormalities may be occurring in some POTS patients. Data from one study suggests abnormalities of atrioventricular conduction and ventricular repolarization in some patients with POTS (Singer, Shen, Opfer-Gehrking, McPhee, Hilz, & Low, 2003). The investigating physicians of this study concluded that these findings may reflect intrinsic cardiac electrophysiologic abnormalities or may be secondary due to abnormalities of cardiac autonomic innervation. Another study suggested a primary sinus node abnormality could be present in a subset of POTS patients (Singer, Shen, Opfer-Gehrking, McPhee, Hilz & Low, 2002). Abnormal rate-dependent P-wave axis behavior has been observed in a small subset of POTS patients. This could be interpreted as a primary sinus node abnormality. However, several publications caution against ablating POTS patients. A Mayo clinic study reported short-term success in five of seven ablated patients with inappropriate sinus tachycardia and postural orthostatic tachycardia features (Shen, Low, Jahangir, Munger, Friedman, Osborn, Stanton, Packer, Rea & Hammill, 2001). However, long-term outcomes were disappointing in these patients. None of the patients experienced complete eradication of symptoms. A follow-up evaluation showed no vast improvement in symptoms, despite better heart rate control. A later publication states "in our laboratory, sinus node modification, total sinus node ablation, or atrioventricular nodal ablation is not recommended for patients with inappropriate sinus tachycardia who have autonomic evidence of postural orthostatic tachycardia" (Shen, 2002). Ablations have reportedly been detrimental to some POTS patients who were misdiagnosed as having inappropriate sinus tachycardia. After the apparently successful elimination of their "sinus tachycardia", they were left with profound orthostatic hypotension (Grubb & Karas, 1999). Cervical stenosis is a condition in which the spinal canal is too narrow, causing compression of the spinal cord and nerve roots. It was once reported that POTS patients with cervical stenosis may benefit from craniovertebral decompression (Rosner, D'Amour & Rowe, 1999). A few patients have reported a decrease or resolution in POTS symptoms after undergoing surgery to correct this condition. Yet other patients have not had any decrease in POTS symptoms after undergoing surgery to correct cervical stenosis. Some physicians are convinced that cervical stenosis can cause POTS, others debate the relationship. Chemical exposure may cause POTS symptoms in some individuals. Researchers at Johns Hopkins University have tested Gulf War vets to see if they have neurally mediated hypotension or POTS. The study aimed to find out if environmental factors such as pesticides, vaccinations or infections are associated with having POTS. Chiari malformation is a condition in which the cerebellar tonsils protrude down into the spinal cord. This can restrict the flow of cerebral spinal fluid. The symptoms of Chiari are similar to those of POTS. A number of Chiari patients have reported being diagnosed with POTS. Some of these patients proclaim a decrease or resolution in POTS symptoms after undergoing surgical correction of their Chiari malformation. Other POTS patients with Chiari malformation have not experienced any benefits from corrective surgery. Some physicians are convinced that Chiari malformation is a cause of POTS, others doubt the relationship. CSF leaks are characterized by a severe headache that becomes worse when upright. This is a key factor in Spinal CSF leaks, but it is also a symptom in POTS patients and they are frequently confused. However, recent research has discovered that patients with CSF frequently have POTS as well, further making the diagnostic process difficult. Since all patients with CSF have orthostatic intolerance related to POTS, there is a danger that further investigation may stop there, causing missed exploration into a CSF leak. Read more Diabetes can produce the symptoms of POTS (Llamas, Garcia, Gaos, Jimenez, Villavicencio, Cueto & Arriaga, 1985). There are different types of diabetes, including diabetes insipidus, that are associated with POTS symptoms. Read more Ehlers-Danlos Syndrome (EDS), a connective tissue disorder, is found in some POTS patients. Physicians propose that these syndromes occur together due to abnormal connective tissue in dependent blood vessels in those with EDS, which permits veins to distend excessively in response to ordinary hydrostatic pressures (Rowe, Barron, Calkins, Maumenee, Tong & Geraghty, 1999).Simply put, this connective tissue abnormality allows excessive amount of blood to pool in these patients' lower limbs when they stand up. There are a variety of types of Ehlers-Danlos syndrome. Classical and Hypermobile EDS (hEDS) were originally reported in orthostatic intolerance patients (Rowe et al., 1999). Many POTS patients with EDS have hEDS (Grubb, 2002). The classical form of Ehlers-Danlos syndrome (types I and II) is characterized by soft, hyperextensible skin; easy bruising; poor wound healing; thin, atrophic scars; hypermobile joints; varicose veins and prematurity of affected newborns (Wenstrup & Hoechstetter, 2001). Mutations in type V collagen are a major cause of the classical type of Ehlers-Danlos syndrome. Clinical features associated with hEDS include soft skin and large and small joint hypermobility (Wenstrup & Hoechstetter, 2001). Skin may be stretchy but scarring tends to be normal. POTS patients with hEDS are often hypermoblie/hyperflexable, double jointed, pale, female and tend to have blond hair and blue eyes (Grubb, 2002). The genetic basis for hEDS is unknown. A wide variety of medical complications may occur with the classical and hypermobile types of EDS. Mitral valve prolapse can occur in all types of EDS and delayed gastric emptying has been observed in hEDS (personal observations, Wenstrup & Hoechstetter, 2001). A significant number of individuals with both the classical form and the hypermobile form have dilation and/or rupture of the ascending aorta (Saliba E et al. 2015, Rozado J et al. 2017). Hiatal hernia has been widely reported in adults with EDS (Nelson, Mouchli Valentin, et al 2015) Read more. As previously stated, premature rupture of the membranes in pregnancy (primarily classical type) and poor wound healing (particularly with severe classical type) may occur. Other complications include a mild to moderate increase in peripartum bleeding, joint dislocations, chronic pain (most common in the hypermobile type), surgical complications and intraoperative problems (more common in the classical than hypermobile type), diverticulitis, problems associated with fragile skin (particularly with the classical type) and motor delay (Leganger, Soborg, Mortensen, et al 2016)Read more. One study on patients with "joint hypermobility syndrome", a disorder similar if not identical to hEDS, showed that 78% had signs of dysautonomia, such as orthostatic hypotension, postural orthostatic tachycardia syndrome and uncategorized orthostatic intolerance (Gazit, Nahir, Grahame, & Jacob, 2003). These patients also had evidence of a-adrenergic and B-adrenergic hyperresponsiveness. The authors of this study note that patients with the joint hypermobility syndrome have apparently intact vagal control of heart rate with disturbed sympathetic function. They further state that "the sympathetic dysregulation associated with joint hypermobility syndrome may have several explanations, such as peripheral neuropathy, blood pooling in the lower limbs, impaired central sympathetic control, or deconditioning due to muscle disuse through pain or fear of pain". Another study of one hundred and seventy women with joint hypermobility syndrome concluded that non-musculoskeletal symptoms are common in patients with joint hypermobility syndrome, and that individuals with these symptoms may express more fatigue, anxiety, migraine, flushing, night sweats, and poor sleep than their peers (Hakim & Grahame, 2004). Read more A group of conditions related to joint hypermobility are hypermobility spectrum disorders (HSD). HSD is diagnosed after all other conditions are rules out, such as EDS and hEDS. HSD can be equal in severity to hEDS and calls for similar care and management. Read more about HSD Read more about EDS through these links Electrical injury has reportedly occurred prior to the development of POTS in a couple of cases (Kanjwal, Karabin, Kanjwal & Grubb, 2009). Gastric bypass surgery may cause orthostatic intolerance in some individuals. Lesions of the autonomic nervous system might be causing POTS in some individuals. Research shows that animals become dysautonomic by selectively lesioning postganglionic sympathetic neurons (Carson, Appalsamy, Diedrich, Davis & Robertson, 2001). Liver disease may contribue to orthostatic intolerance. Compensated Cirrhosis is a condition in which the liver is damaged but is able to compensate for it. This condition coincides with hypovolemia and vasodilation. POTS, as well as peripheral blood pooling and decreased arterial tone, has been found in some patients (Hartleb, Rudzki, Karpel, Becker, Waluga, Boldys, Nowak & Nowak, 1979). Mast-cell activation disorders may play a role in the development of POTS in some individuals. Some patients with orthostatic intolerance suffer from episodes of flushing, palpitations, shortness of breath, chest discomfort, headache, lightheadedness, hypotension or hypertension and occasionally syncope (Jacob & Biaggioni, 1999). Exercise may trigger an attack (Shibao, Arzubiaga, Roberts, Raj, Black, Harris & Biaggioni, 2005). Patients may complain of increased fatigue, sleepiness, increased urination and/or diarrhea after an attack (Jacob & Biaggioni, 1999). Symptoms of orthostatic intolerance often worsen after an episode. An increase in urinary methylhistamine, a marker of mast-cell activation, can be found in these patients. Mast-cell activation results in the release of the vasodilator histamine, which may contribute to symptoms of POTS. Other mast cell mediators, such as plasma prostaglandin 2, may contribute to symptoms as well. Urinary histamine is often measured in the evaluation of flushing, but it is less specific than methylhistamine and not useful in the diagnosis of mast-cell activation (Shibao et al., 2005). Patients should be instructed to collect urine for a 4-hour period immediately after a severe spontaneous flushing episode. Urinary methylhistamine is usually normal between episodes in patients with mast-cell activation disorders, although the patients may experience chronic fatigue and orthostatic intolerance between episodes, which can lead to a disabling condition (Shibao et al., 2005). Beta blockers should be used with caution, if at all, in those with mast-cell activation disorders (Shibao et al., 2005). Beta blockers may trigger mast-cell activation. Read more about MCAS Mitochondrial disease is sometimes found in patients who present with autonomic dysfunction. Read more Neuropathy may be involved in the development of POTS in some individuals. One study showed that POTS may be, in part, a manifestation of autonomic cardiac neuropathy (Haensch, Lerch, Schlemmer, Jigalin & Isenmann, 2009). Sympathetic denervation of the legs might be the cause of POTS in some patients as well. Nitric Oxide deficit may play a role in POTS symptoms. Nitric Oxide (NO) is a very simple molecule whose job it is to control blood vessel size with changes in blood flow, changes in blood vessels during inflammation and blood vessel leakiness (Stewart, 2005). Some POTS patients have a deficit of nitric oxide (Stewart, Taneja, Glover & Medow, 2008.). This deficit may relate to the nitric oxide synthase molecule called nNOS, but it also has a compelling relationship with the hormone angiotensin-II.Together angiotensin-II and NO may help to regulate sympathetic nerve activity in the brain and also in certain peripheral nerves (such as the splanchnic circulation). Moreover, angiotensin-II can result in increased oxidative stress which can itself reduce NO (Dr. Julian Stewart, personal communication, November 28, 2007). Researchers have found that NO levels can be increased by blocking the most important receptor for angiotensin-II. This may lead to treatments in the future in select groups of POTS patients. Norepinephrine transporter deficiency is thought to cause POTS in some patients. These patients have an abnormality in the clearance of norepinephrine from the synaptic cleft. The body normally recycles norepinephrine. The protein that recycles norepinephrine doesn't work well in people with the norepinephrine transporter deficiency (Grubb, 2002). Excessive amounts of norepinephrine is spilled over. These people soon become depleted of norepinephrine if the neuron is continually stimulated (Grubb, 2002). They go from having excessive amounts of norepinephrine to having no norepinephrine, at which point they crash. Read More Other researchers have reportedly discovered hypermethylation of the norepinephrine transporter (NET) gene promoter in POTS patients (Esler, Alvarenga, Pier, Richards, El-Osta, Barton, Haikerwal, Kaye, Schlaich, Guo, Jennings, Socratous & Lambert, 2006) In these patients, the gene for the protein that transports norepinephrine (NET) is turned off because its promoter is turned off. Further studies are being conducted to determine whether hypermethylation of the NET gene promoter is a mechanism or cause of POTS. The nutcracker phenomenon has reportedly produced POTS symptoms in some individuals. Nutcracker phenomenon (NC) is the congestion of the left renal vein due to its compression by the aorta and the superior mesenteric artery (Takahashi, Ohta, Sano, Kuroda, Kaji, Matusuki & Matsuo, 2000). The main and common findings of one study on pediatric NC patients were chronic fatigue associated with orthostatic hypotension and/or postural tachycardia (Takahashi, Ohta, Sano, Kuroda, Kaji, Matusuki & Matsuo, 2000). The authors of this study point out that "the originally reported symptom of NC is renal bleeding. However, reported 'renal bleeding' patients, including ours, have no complaints of chronic fatigue and our 'chronic fatigue' (NC) patients have no renal bleeding". Some of these patients did report fibromyalgia type pain. Some patients had proteinuria, others had no urinary abnormalities. The authors of this study explain the various ways in which NC might affect autonomic function: First, severe congestion in the kidney may cause the expansion of the renal venous bed, which would affect the renin-angiotensin system. Secondly, severe congestion in the adrenal medulla, which is innervated by sympathetic nerves, may disturb a complex set of central neural connections controlling the sympathoadrenal system. On the other hand, overproduction or night retention of catecholamines might be responsible for the various symptoms of pediatric chronic fatigue syndrome (Takahashi, Ohta, Sano, Kuroda, Kaji, Matusuki & Matsuo, 2000). The nutcracker phenomenon occurs in adults as well as children. Transluminal balloon angioplasty has successfully been used to treat compression of the left renal vein between the aorta and superior mesenteric artery (Takahashi, Sano & Matsuo, 2000). The methods used to diagnose nutcracker phenomenon include Doppler US, MRI and three-dimensional helical computed tomography. Dr. Takahashi (personal communication, September 8, 2002) explains the procedures for testing as follows: Conventional ultrasound requires patients to be examined for left renal vein obstruction in 4 positions: supine, semisitting, upright and prone. Nonvisualization of the left renal vein lumen or absence of the left renal vein wall between the aorta and superior mesenteric artery is regarded as signifying left renal vein obstruction. Doppler color flow imaging can be used to locate a blue-colored blood stream flowing to the dorsal direction. This is a collateral vein flowing from the left renal vein into the paravertebral vein. With MRI, oblique coronal images along the left renal vein, and also axial images, are recommended to visualize the collateral veins around the left renal vein. The relationship between headaches and nutcracker syndrome is explored in a recent study (Stuberrud, Cheema, et al 2020) Read more Nutritional deficiencies can lead to autonomic dysfunction. The B vitamins 1, 3, 6, and 12 have been reportedly linked to dysautonomia symptoms (Autonomic Dysfunction, 2000). Folic acid deficiency (B9) can also cause POTS symptoms. Other neurological conditions, such as multiple sclerosis, are sometimes associated with autonomic dysfunction. Parasites can transmit diseases, such as Chagas, that can cause POTS symptoms. Some patients report developing POTS after having Lyme disease. Porphyrias have been associated with POTS symptoms (Stewart & Hensley, 1981). Porphyrias are rare, mainly genetic disorders that affect the body's ability to make hemoglobin. They are caused by deficiencies in enzymes involved in the synthesis of heme. Porphyria patients are often overly sensitive to sunlight. It is important for physicians to rule out porphyrias before prescribing medication to POTS patients. Some medications that are considered unsafe for porphyria patients are used to treat dysautonomia. Read more Syringomyelia is a condition in which a cyst grows within the spinal cord. POTS can occur in patients with this condition. Syringomyelia is similar to POTS in that it usually occurs between the ages of 25 and 40, it can have a sudden onset, some patients have Chiari malformation and some patients may experience long periods of stability. The symptoms of syringomyelia can worsen with straining or any activity that causes cerebrospinal fluid to fluctuate. Many POTS patients also report a worsening of symptoms upon straining. Partial sympathetic denervation of the legs in those with syringomyelia might explain the occasional occurrence of postural tachycardia syndrome (NINDS Syringomyelia Information Page, 2020). Read more Tumors can lead to autonomic dysfunction. Tumors, such as pheochromocytoma and neuroblastoma, can secrete catecholamines that affect the autonomic system. Pelvic ganglioneuroma is another type of tumor that has also been associated with autonomic dysfunction (Gentile, Rainero, Luda & Pinessi, 2001). Tumors can cause compression, which directly affects the autonomic nervous system. Tumors are also capable of having a paraneoplastic effect on the ANS by producing autoantibodies against acetylcholine receptors in the autonomic ganglia (Mayo Clinic Fact Sheet, 2020). Thyroid disease can cause symptoms that are similar to those of POTS. Viruses are thought to be the provoking factor in approximately 50% of POTS patients (Low & Schondorf, 1997, p. 279). There are reports of dysautonomia occurring after the Epstein-Barr virus (Itoh, Oishi, Ohnishi, Murai & Imawatari, 1993). Viruses may directly affect the autonomic nervous system or lead to an immune pathogenesis (Grubb, 2000). Roughly one-half of post-viral POTS patients will make a good practical recovery over a 2-5 year period (Grubb, Kanjwal & Kosinski, 2006). These are but a few of the possible causes of POTS symptoms. More information on causes of autonomic dysfunction can be located at the National Dysautonomia Research Foundation. References 1. Autonomic Dysfunction. (2000). The WorldWide Anaesthetist. http://anaesthetist.com/anaes/patient/ans.htm 2. Bernstein, R. S., Pierson, R. N. 3rd., Ryan, S. F., & Crespin S. B. (1979). Adipose cell morphology and control of lipolysis in a patient with partial lipodystrophy. Metabolism, 28, 519-526. PMID: 449692 [PubMed - indexed for MEDLINE] 3. Carson, R. P., Appalsamy, M., Diedrich, A., Davis, T. L., & Robertson, D. (2001). Animal model of neuropathic tachycardia syndrome. Hypertension, 37, 1357-1361. Full text: http://hyper.ahajournals.org/cgi/content/full/37/6/1357 4. Esler M., Alvarenga M., Pier C., Richards J., El-Osta A., Barton D., Haikerwal D., Kaye D., Schlaich M., Guo L., Jennings G., Socratous F., & Lambert G. (2006). The neuronal noradrenaline transporter, anxiety and cardiovascular disease. J Psychopharmacol. Jul;20(4 Suppl):60-6. PubMed 5. Gazit, Y., Nahir, A. M., Grahame, R., & Jacob, G. (2003). Dysautonomia in the joint hypermobility syndrome. The American Journal of Medicine. 115(1), 33-40. PubMed 6. Gentile, S., Rainero, I., Luda, E., & Pinessi, L. (2001). Autonomic dysfunction associated with multiple pelvic ganglioneuromas. Acta Neurologica Scandinavica, 104(1), 54-56. PMID: 11442444 [PubMed - indexed for MEDLINE] 7. Gibbons C. H. & Freeman R. (2009). Antibody titers predict clinical features of autoimmune autonomic ganglionopathy. Auton Neurosci. 12;146(1-2), 8-12. PubMed. 8. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 9. Grubb, B. P. (2002, October). The heterogeneity of symptoms related to dysautonomia. Symposium conducted at the meeting of the National Dysautonomia Research Foundation Northwest Ohio Support Group. Toledo, Ohio. 10. Grubb B. P., Kanjwal, Y., & Kosinski, D. J. (2006). The postural tachycardia syndrome: A concise guide to diagnosis and management. J Cardiovasc Electrophysiol., 17, 108-112. 11. Grubb, B. P., & Karas, B. (1999). Clinical disorders of the autonomic nervous system associated with orthostatic intolerance. Pacing and Clinical Electrophysiology, 22, 798-810. Full text: http://www.ndrf.org/PDF%20Files/disorders.PDF 12. Haensch, C. A., Lerch, H., Schlemmer, H., Jigalin, A., & Isenmann, S. (2009). Cardiac Neurotransmission Imaging with 123I-Meta-iodobenzylguanidine in Postural Tachycardia Syndrome. J Neurol Neurosurg Psychiatry. 2009 Aug 16. PubMed 13. Hakim, A. J., & Grahame, R. (2004). Letters to the editor: Non-musculoskeletal symptoms in joint hypermobility syndrome. Indirect evidence for autonomic dysfunction? Rheumatology. 43, 1194-1195. Full Text 14. Hartleb, M., Rudzki, K., Karpel, E., Becker, A., Waluga, M., Boldys, H., Nowak, A., & Nowak, S. (1979). Cardiovascular status after postural change in compensated cirrhosis: an argument for vasodilatory concept. Liver, 17(1), 1-6. PMID: 9062872 [PubMed - indexed for MEDLINE] 15. Healthline Scripts: Cardiac Atrophy. (1998). National Space Biomedical Research Institute. 16. Itoh, Y., Oishi, T., Ohnishi, A., Murai, Y., & Imawatari, R. (1993). [Acute cerebellar ataxia with sympathotonic orthostatic hypotension following Epstein-Barr virus infection--a case report]. Rinsho Shinkeigaku, 33, 503-506. PMID: 8395987 [PubMed - indexed for MEDLINE] 17. Jacob, G., & Biaggioni I. (1999). Idiopathic orthostatic intolerance and postural tachycardia syndromes. The American Journal of the Medical Sciences, 317, 88-101. PMID: 10037112 [PubMed - indexed for MEDLINE] 18. Kanjwal, K., Karabin, B., Kanjwal, Y., & Grubb, B.P. (2009). Postural orthostatic tachycardia syndrome: a rare complication following electrical injury. Pacing and Clinical Electrophysiology. Dec 10. 19. Llamas, E. G., Garcia, R. G., Gaos, C. Jr., Jimenez, J. L., Villavicencio, R., Cueto, L., & Arriaga, G. J. (1985). Cardiac autonomic neauropathy in the diabetic patient. Archivos del Instituto de Cardiologia de Mexico, 55, 247-256. Spanish. PMID: 2932078 [PubMed - indexed for MEDLINE] 20. Low, P. A., Schondorf, R. (1996). Postural tachycardia syndrome. In D. Robertson, P. A. Low & R. J. Polinsky (Eds.), Primer on the autonomic nervous system (p. 279). San Diego, CA: Academic Press. 21. Mitka, M. (2002). Returning astronaut study helps some reeling patients. The Journal of the American Medical Association, 287, 837. 22. Nand, N., Mohan R., Khosla, S. N., & Kumar P. (1989). Autonomic function tests in cases of chronic severe anaemia. Journal of the Association of Physicians of India, 37, 508-510. PMID: 2621185 [PubMed - indexed for MEDLINE] 23. NINDS Syringomyelia Information Page. (2001). National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/syringomyelia/syringomyelia.htm 24. Raj, S. R., Biaggioni, I., Yamhure, P. C., Black, B. K., Paranjape, S. Y., Byrne, D. W., & Robertson, D. (2005). Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Circulation. 111(13), 1574-1582. 25. Rosner, M. J., D'Amour, P., & Rowe, P. C. (1999, September). Neurally Mediated Hypotension: its Surgical Evaluation, Management and Early Outcome as Part of the Fibromyalgia—Chronic Fatigue Syndrome. National Fibromyalgia Research Association's Subgroups in Fibromyalgia Symposium. Portland, Oregon. http://www.nfra.net/SubRosner2.htm 26. Rowe, P. C., Barron, D. F., Calkins, H., Maumenee, I. H., Tong, P. Y., & Geraghty, M. T. (1999). Orthostatic intolerance and chronic fatigue syndrome associated with Ehlers-Danlos syndrome. Journal of Pediatrics, 135, 494-499. PMID: 10518084 [PubMed - indexed for MEDLINE] 27. Shen, W. K. (2002). Modification and ablation for inappropriate sinus tachycardia: current status. Cardiac Electrophysiology Review. 6(4), 349-355. PubMed 28. Shen, W. K., Low, P.A., Jahangir, A., Munger, T. M., Friedman, P. A., Osborn, M. J., Stanton, M. S., Packer, D. L., Rea, R. F., Hammill, S. C. (2001). Is sinus node modification appropriate for inappropriate sinus tachycardia with features of postural orthostatic tachycardia syndrome? Pacing & Clinical Electrophysiology, 24(2), 217-230. PubMed 29. Singer, W., Shen, W. K., Opfer-Gehrking, T.L., McPhee, B. R., Hilz, M. J., & Low, P.A. (2002). Evidence of an intrinsic sinus node abnormality in patients with postural tachycardia syndrome. Mayo Clinic Proceedings, 77, 246-252. 30. Singer, W., Shen, W. K., Opfer-Gehrking, T.L., McPhee, B. R., Hilz, M. J., & Low, P.A. (2003). Heart rate-dependent electrocardiogram abnormalities in patients with postural tachycardia syndrome. Autononomic Neuroscience, 31, 103(1-2), 106-113. PMID: 12531404 [PubMed - in process] 31. Singh, N. K., Jaiswal, A. K., Misra, S., & Srivastava, P. K. (1987). Assessment of autonomic function in Guillain-Barre syndrome and its prognostic implications. Acta Neurologica Scandinavica, 75, 101-105. PMID: 3577674 [PubMed -indexed for MEDLINE] 32. Steinmann, B., Royce, P. M., Superti-Furga, A. (1993). The Ehlers-Danlos syndrome. In: P. M. Royce & B. Steinman (Eds), Connective tissue and its heritable disorders (pp. 351-408).New York: Wiley-Liss, Inc. 33. Stewart, J. M. Local vasoconstriction in postural tachycardia syndrome. Retrieved April 19, 2005, from Center for Pediatric Hypotension. 34. Stewart, J. M., Ocon, A. J., Clarke, D., Taneja, I., Medow, M. S. (2009). Defects in cutaneous angiotensin-converting enzyme 2 and angiotensin-(1-7) production in postural tachycardia syndrome. Hypertension. 53(5), 767-774. PubMed 35. Stewart, J. M., Taneja, I., Glover, J., & Medow, M. S. (2008). Angiotensin II type 1 receptor blockade corrects cutaneous nitric oxide deficit in postural tachycardia syndrome. American Journal of Physiology. Heart and Circulatory Physiology. 294(1), H466-73. PubMed 36. Stewart, P. M., & Hensley, W. J. (1981). An acute attack of variegate porphyria complicated by severe autonomic neuropathy. Australian and New Zealand Journal of Medicine, 11(1), 82-83. PMID: 6941785 [PubMed - indexed for MEDLINE] 37. Takahashi, Y., Ohta, S., Sano, A., Kuroda, Y., Kaji, Y., Matusuki, M., & Matsuo, M. (2000). Does severe nutcracker phenomenon cause pediatric chronic fatigue? Clinical Nephrology, 53, 174-181. PMID: 10749295 [PubMed - indexed for MEDLINE] 38. Takahashi, Y., Sano, A., Matsuo, M. (2000). An effective "transluminal balloon angioplasty" therapy for pediatric chronic fatigue syndrome with nutcracker phenomenon. Clinical Nephrology, 53, 77-78. PMID: 10661488 [PubMed - indexed for MEDLINE] 39. Wenstrup, R. J., & Hoechstetter, L. B. (2001). The Ehlers-Danlos syndromes. In S. B. Cassidy & J. E. Allanson (Eds.) , Management of genetic syndromes (pp. 131-149). New York: Wiley-Liss, Inc. 40. Vernino, S., Low, P. A., Fealey, R. D., Stewart, J. D., Farrugia, G., & Lennon, V. A. (2000). Autoantibodies to Ganglionic Acetylcholine Receptors in Autoimmune Autonomic Neuropathies. The New England Journal of Medicine, 343, 847-855. http://content.nejm.org/cgi/content/abstract/343/12/847

POTS symptoms can occur due to many different abnormalities in the body. Some disorders associated with POTS symptoms have been identified. Many of the causes of POTS still remain unknown. It can be difficult to distinguish between the causes and effects of this disorder, which further complicates matters. There are a multitude of disorders that can produce POTS-like symptoms. It is important that physicians attempt to find possible causes of a patient's orthostatic intolerance, as many secondary disorders are treatable. Some of the entities that may be contributing to one's orthostatic intolerance include: Adrenal disorders, such as Addison's disease,can produce symptoms that mimic POTS. Anemia patients sometimes exhibit the symptoms of POTS (Nand, Mohan, Khosla & Kumar, 1989). Some patients may have folic acid deficiency, which is contributing to their anemia and POTS symptoms. POTS patients may have a form of hidden anemia where the standard tests, such as hemoglobin and hematocrit, are relatively normal even though the patient has a severe anemia (Raj, Biaggioni, Yamhure, Black, Paranjape, Byrne & Robertson, 2005). A formal radioisotope dilution assessment of blood volumes was required to discover the red blood cell volume deficit documented in a 2005 study of POTS patients (Raj, et. al, 2005). The authors of this study state that it is possible a deficit in erythropoietin production might play a pathophysiological role in POTS, although this is not yet clear. Angiotensin II has been found to be increased in some people with postural orthostatic tachycardia syndrome. The results from one study imply impaired catabolism of Angiotensin II through the angiotensin-converting enzyme 2 pathway. Vasoconstriction in POTS may result from a reduction in Ang-(1-7) and an increase in angiotensin II (Stewart, Ocon, Clarke, Taneja & Medow, 2009). The angiotensin II type I receptor gene may be responsible for some orthostatic disorders.The NIH has researched vascular responsiveness in subjects with polymorphisms of the angiotensin II type I receptor gene. Angiotensin II is a hormone that constricts blood vessels by attaching to a protein on the blood vessels. People can have a variety of forms of this protein. Researchers have looked for differences in the gene that makes this protein to determine if these genetic differences have any effect on blood pressure. Autoimmune disorders,such as Guillain-Barre (Singh, Jaiswal, Misra & Srivastava, 1987) and lupus are suspected of causing POTS symptoms in some individuals. Researchers have discovered an antibody to neuronal nicotinic acetylcholine receptors of autonomic ganglia (Vernino, Low, Fealey, Stewart, Farrugia & Lennon, 2000). Some people with POTS have an antibody titer test that is positive to this antibody. Patients with orthostatic intolerance, anhidrosis, constipation, urinary dysfunction, sicca syndrome and pupillary dysfunction had higher antibody titers than subjects that did not (Gibbons & Freeman, 2009). Patients with the highest levels of these ganglionic-receptor-binding antibodies have the most severe autonomic dysfunction. Physicians have discovered that antibody levels lower as some patients improve, which suggests a cause and effect relationship. Patients interested in being tested for the ganglionic antibody should have their physician contact: Mayo Medical Laboratories 1-800-533-1710 mml@mayo.edu Cardiac atrophy has been pinpointed as the cause of orthostatic intolerance in astronauts. Research has shown that astronauts' hearts actually shrink and stiffen due to the reduced blood volume caused by microgravity (Mitka, 2002). Researchers want to find out if the cardiac atrophy is entirely reversible, and if the loss of mass can reach a point where it leads to catastrophic consequences (Healthline Scripts: Cardiac Atrophy, 1998). This finding may have implications for people who develop orthostatic intolerance due to being bedridden. Whether or not the finding can be applied to a percentage of patients who develop orthostatic intolerance for other reasons has yet to be proven. Cardiac disease can cause POTS symptoms. Most physicians are quick to rule cardiac disease out. Cardiac electrophysiologic property abnormalities may be occurring in some POTS patients. Data from one study suggests abnormalities of atrioventricular conduction and ventricular repolarization in some patients with POTS (Singer, Shen, Opfer-Gehrking, McPhee, Hilz, & Low, 2003). The investigating physicians of this study concluded that these findings may reflect intrinsic cardiac electrophysiologic abnormalities or may be secondary due to abnormalities of cardiac autonomic innervation. Another study suggested a primary sinus node abnormality could be present in a subset of POTS patients (Singer, Shen, Opfer-Gehrking, McPhee, Hilz & Low, 2002). Abnormal rate-dependent P-wave axis behavior has been observed in a small subset of POTS patients. This could be interpreted as a primary sinus node abnormality. However, several publications caution against ablating POTS patients. A Mayo clinic study reported short-term success in five of seven ablated patients with inappropriate sinus tachycardia and postural orthostatic tachycardia features (Shen, Low, Jahangir, Munger, Friedman, Osborn, Stanton, Packer, Rea & Hammill, 2001). However, long-term outcomes were disappointing in these patients. None of the patients experienced complete eradication of symptoms. A follow-up evaluation showed no vast improvement in symptoms, despite better heart rate control. A later publication states "in our laboratory, sinus node modification, total sinus node ablation, or atrioventricular nodal ablation is not recommended for patients with inappropriate sinus tachycardia who have autonomic evidence of postural orthostatic tachycardia" (Shen, 2002). Ablations have reportedly been detrimental to some POTS patients who were misdiagnosed as having inappropriate sinus tachycardia. After the apparently successful elimination of their "sinus tachycardia", they were left with profound orthostatic hypotension (Grubb & Karas, 1999). Cervical stenosis is a condition in which the spinal canal is too narrow, causing compression of the spinal cord and nerve roots. It was once reported that POTS patients with cervical stenosis may benefit from craniovertebral decompression (Rosner, D'Amour & Rowe, 1999). A few patients have reported a decrease or resolution in POTS symptoms after undergoing surgery to correct this condition. Yet other patients have not had any decrease in POTS symptoms after undergoing surgery to correct cervical stenosis. Some physicians are convinced that cervical stenosis can cause POTS, others debate the relationship. Chemical exposure may cause POTS symptoms in some individuals. Researchers at Johns Hopkins University have tested Gulf War vets to see if they have neurally mediated hypotension or POTS. The study aimed to find out if environmental factors such as pesticides, vaccinations or infections are associated with having POTS. Chiari malformation is a condition in which the cerebellar tonsils protrude down into the spinal cord. This can restrict the flow of cerebral spinal fluid. The symptoms of Chiari are similar to those of POTS. A number of Chiari patients have reported being diagnosed with POTS. Some of these patients proclaim a decrease or resolution in POTS symptoms after undergoing surgical correction of their Chiari malformation. Other POTS patients with Chiari malformation have not experienced any benefits from corrective surgery. Some physicians are convinced that Chiari malformation is a cause of POTS, others doubt the relationship. Physicians from the NIH and The Chiari Institute believe their is a connection between Ehlers-Danlos syndrome, POTS and Chiari 1 malformation. Read More Diabetes can produce the symptoms of POTS (Llamas, Garcia, Gaos, Jimenez, Villavicencio, Cueto & Arriaga, 1985). There are different types of diabetes, including diabetes insipidus, that are associated with POTS symptoms. Read more Ehlers-Danlos Syndrome (EDS), a connective tissue disorder,is found in some POTS patients. Physicians propose that these syndromes occur together due to abnormal connective tissue in dependent blood vessels in those with EDS, which permits veins to distend excessively in response to ordinary hydrostatic pressures (Rowe, Barron, Calkins, Maumenee, Tong & Geraghty, 1999). Simply put, this connective tissue abnormality allows excessive amounts of blood to pool in these patients' lower limbs when they stand up. There are a variety of types of Ehlers-Danlos syndrome. Classical and type III EDS were originally reported in orthostatic intolerance patients (Rowe et al., 1999). Many POTS patients with EDS have type III (Grubb, 2002). The classical form of Ehlers-Danlos syndrome (types I and II) is characterized by soft, hyperextensible skin; easy bruising; poor wound healing; thin, atrophic scars; hypermobile joints; varicose veins and prematurity of affected newborns (Wenstrup & Hoechstetter, 2001). Mutations in type V collagen are a major cause of the classical type of Ehlers-Danlos syndrome. Clinical features associated with EDS III include soft skin and large and small joint hypermobility (Wenstrup & Hoechstetter, 2001). Skin may be stretchy but scarring tends to be normal. POTS patients with EDS III are often hypermoblie/hyperflexable, double jointed, pale, female and tend to have blond hair and blue eyes (Grubb, 2002). The genetic basis for EDS III is unknown. A wide variety of medical complications may occur with the classical and hypermobile types of EDS. Mitral valve prolapse can occur in all types of EDS and delayed gastric emptying has been observed in type III (personal observations, Wenstrup & Hoechstetter, 2001). A significant number of individuals with both the classical form and the hypermobile form have dilation and/or rupture of the ascending aorta (Wenstrup & Hoechstetter, 2001). Hiatal hernia has been widely reported in adults with EDS (Steinman, Royce & Superti-Furga, 1993). As previously stated, premature rupture of the membranes in pregnancy (primarily classical type) and poor wound healing (particularly with severe classical type) may occur. Other complications include a mild to moderate increase in peripartum bleeding, joint dislocations, chronic pain (most common in the hypermobile type), surgical complications and intraoperative problems (more common in the classical than hypermobile type), diverticulitis, problems associated with fragile skin (particularly with the classical type) and motor delay (Wenstrup & Hoechstetter, 2001). One study on patients with "joint hypermobility syndrome", a disorder similar if not identical to EDS III, showed that 78% had signs of dysautonomia, such as orthostatic hypotension, postural orthostatic tachycardia syndrome and uncategorized orthostatic intolerance (Gazit, Nahir, Grahame, & Jacob, 2003). These patients also had evidence of a-adrenergic and B-adrenergic hyperresponsiveness. The authors of this study note that patients with the joint hypermobility syndrome have apparently intact vagal control of heart rate with disturbed sympathetic function. They further state that "the sympathetic dysregulation associated with joint hypermobility syndrome may have several explanations, such as peripheral neuropathy, blood pooling in the lower limbs, impaired central sympathetic control, or deconditioning due to muscle disuse through pain or fear of pain". Another study of one hundred and seventy women with joint hypermobility syndrome concluded that non-musculoskeletal symptoms are common in patients with joint hypermobility syndrome, and that individuals with these symptoms may express more fatigue, anxiety, migraine, flushing, night sweats, and poor sleep than their peers (Hakim & Grahame, 2004). Read more Electrical injury has reportedly occurred prior to the development of POTS in a couple of cases (Kanjwal, Karabin, Kanjwal & Grubb, 2009). Gastric bypass surgery may cause orthostatic intolerance in some individuals. Lesions of the autonomic nervous system might be causing POTS in some individuals. Research shows that animals become dysautonomic by selectively lesioning postganglionic sympathetic neurons (Carson, Appalsamy, Diedrich, Davis & Robertson, 2001). Lipodystrophy a rare metabolic disorder, has been associated with POTS symptoms (Bernstein, Pierson, Ryan & Crespin, 1979). Liver disease may contribue to orthostatic intolerance. Compensated Cirrhosis is a condition in which the liver is damaged but is able to compensate for it. This condition coincides with hypovolemia and vasodilation. POTS, as well as peripheral blood pooling and decreased arterial tone, has been found in some patients (Hartleb, Rudzki, Karpel, Becker, Waluga, Boldys, Nowak & Nowak, 1979). Mast-cell activation disorders may play a role in the development of POTS in some individuals. Some patients with orthostatic intolerance suffer from episodes of flushing, palpitations, shortness of breath, chest discomfort, headache, lightheadedness, hypotension or hypertension and occasionally syncope (Jacob & Biaggioni, 1999). Exercise may trigger an attack (Shibao, Arzubiaga, Roberts, Raj, Black, Harris & Biaggioni, 2005). Patients may complain of increased fatigue, sleepiness, increased urination and/or diarrhea after an attack (Jacob & Biaggioni, 1999). Symptoms of orthostatic intolerance often worsen after an episode. An increase in urinary methylhistamine, a marker of mast-cell activation, can be found in these patients. Mast-cell activation results in the release of the vasodilator histamine, which may contribute to symptoms of POTS. Other mast cell mediators, such as plasma prostaglandin 2, may contribute to symptoms as well. Urinary histamine is often measured in the evaluation of flushing, but it is less specific than methylhistamine and not useful in the diagnosis of mast-cell activation (Shibao et al., 2005). Patients should be instructed to collect urine for a 4-hour period immediately after a severe spontaneous flushing episode. Urinary methylhistamine is usually normal between episodes in patients with mast-cell activation disorders, although the patients may experience chronic fatigue and orthostatic intolerance between episodes, which can lead to a disabling condition (Shibao et al., 2005). Beta blockers should be used with caution, if at all, in those with mast-cell activation disorders (Shibao et al., 2005). Beta blockers may trigger mast-cell activation. Mitochondrial disease is sometimes found in patients who present with autonomic dysfunction. Read more Neuropathy may be involved in the development of POTS in some individuals. One study showed that POTS may be, in part, a manifestation of autonomic cardiac neuropathy (Haensch, Lerch, Schlemmer, Jigalin & Isenmann, 2009). Sympathetic denervation of the legs might be the cause of POTS in some patients as well. Nitric Oxide deficit may play a role in POTS symptoms. Nitric Oxide (NO) is a very simple molecule whose job it is to control blood vessel size with changes in blood flow, changes in blood vessels during inflammation and blood vessel leakiness (Stewart, 2005). Some POTS patients have a deficit of nitric oxide (Stewart, Taneja, Glover & Medow, 2008.). This deficit may relate to the nitric oxide synthase molecule called nNOS, but it also has a compelling relationship with the hormone angiotensin-II.Together angiotensin-II and NO may help to regulate sympathetic nerve activity in the brain and also in certain peripheral nerves (such as the splanchnic circulation). Moreover, angiotensin-II can result in increased oxidative stress which can itself reduce NO (Dr. Julian Stewart, personal communication, November 28, 2007). Researchers have found that NO levels can be increased by blocking the most important receptor for angiotensin-II. This may lead to treatments in the future in select groups of POTS patients. Norepinephrine transporter deficiency is thought to cause POTS in some patients. These patients have an abnormality in the clearance of norepinephrine from the synaptic cleft. The body normally recycles norepinephrine. The protein that recycles norepinephrine doesn't work well in people with the norepinephrine transporter deficiency (Grubb, 2002). Excessive amounts of norepinephrine is spilled over. These people soon become depleted of norepinephrine if the neuron is continually stimulated (Grubb, 2002). They go from having excessive amounts of norepinephrine to having no norepinephrine, at which point they crash. Read More Other researchers have reportedly discovered hypermethylation of the norepinephrine transporter (NET) gene promoter in POTS patients (Esler, Alvarenga, Pier, Richards, El-Osta, Barton, Haikerwal, Kaye, Schlaich, Guo, Jennings, Socratous & Lambert, 2006) In these patients, the gene for the protein that transports norepinephrine (NET) is turned off because its promoter is turned off. Further studies are being conducted to determine whether hypermethylation of the NET gene promoter is a mechanism or cause of POTS. The nutcracker phenomenon has reportedly produced POTS symptoms in some individuals. Nutcracker phenomenon (NC) is the congestion of the left renal vein due to its compression by the aorta and the superior mesenteric artery (Takahashi, Ohta, Sano, Kuroda, Kaji, Matusuki & Matsuo, 2000). The main and common findings of one study on pediatric NC patients were chronic fatigue associated with orthostatic hypotension and/or postural tachycardia (Takahashi, Ohta, Sano, Kuroda, Kaji, Matusuki & Matsuo, 2000). The authors of this study point out that "the originally reported symptom of NC is renal bleeding. However, reported 'renal bleeding' patients, including ours, have no complaints of chronic fatigue and our 'chronic fatigue' (NC) patients have no renal bleeding". Some of these patients did report fibromyalgia type pain. Some patients had proteinuria, others had no urinary abnormalities. The authors of this study explain the various ways in which NC might affect autonomic function: First, severe congestion in the kidney may cause the expansion of the renal venous bed, which would affect the renin-angiotensin system. Secondly, severe congestion in the adrenal medulla, which is innervated by sympathetic nerves, may disturb a complex set of central neural connections controlling the sympathoadrenal system. On the other hand, overproduction or night retention of catecholamines might be responsible for the various symptoms of pediatric chronic fatigue syndrome (Takahashi, Ohta, Sano, Kuroda, Kaji, Matusuki & Matsuo, 2000). The nutcracker phenomenon occurs in adults as well as children. Transluminal balloon angioplasty has successfully been used to treat compression of the left renal vein between the aorta and superior mesenteric artery (Takahashi, Sano & Matsuo, 2000). The methods used to diagnose nutcracker phenomenon include Doppler US, MRI and three-dimensional helical computed tomography. Dr. Takahashi (personal communication, September 8, 2002) explains the procedures for testing as follows: Conventional ultrasound requires patients to be examined for left renal vein obstruction in 4 positions: supine, semisitting, upright and prone. Nonvisualization of the left renal vein lumen or absence of the left renal vein wall between the aorta and superior mesenteric artery is regarded as signifying left renal vein obstruction. Doppler color flow imaging can be used to locate a blue-colored blood stream flowing to the dorsal direction. This is a collateral vein flowing from the left renal vein into the paravertebral vein. With MRI, oblique coronal images along the left renal vein, and also axial images, are recommended to visualize the collateral veins around the left renal vein. Read more Nutritional deficiencies can lead to autonomic dysfunction. The B vitamins 1, 3, 6, and 12 have been reportedly linked to dysautonomia symptoms (Autonomic Dysfunction, 2000). Folic acid deficiency (B9) can also cause POTS symptoms. Other neurological conditions, such as multiple sclerosis, are sometimes associated with autonomic dysfunction. Parasites can transmit diseases, such as Chagas, that can cause POTS symptoms. Some patients report developing POTS after having Lyme disease. Porphyrias have been associated with POTS symptoms (Stewart & Hensley, 1981). Porphyrias are rare, mainly genetic disorders that affect the body's ability to make hemoglobin. They are caused by deficiencies in enzymes involved in the synthesis of heme. Porphyria patients are often overly sensitive to sunlight. It is important for physicians to rule out porphyrias before prescribing medication to POTS patients. Some medications that are considered unsafe for porphyria patients are used to treat dysautonomia. Read more Syringomyelia is a condition in which a cyst grows within the spinal cord. POTS can occur in patients with this condition. Syringomyelia is similar to POTS in that it usually occurs between the ages of 25 and 40, it can have a sudden onset, some patients have Chiari malformation and some patients may experience long periods of stability. The symptoms of syringomyelia can worsen with straining or any activity that causes cerebrospinal fluid to fluctuate. Many POTS patients also report a worsening of symptoms upon straining. Partial sympathetic denervation of the legs in those with syringomyelia might explain the occasional occurrence of postural tachycardia syndrome (NINDS Syringomyelia Information Page, 2001). Read more Tumors can lead to autonomic dysfunction. Tumors, such as pheochromocytoma and neuroblastoma, can secrete catecholamines that affect the autonomic system. Pelvic ganglioneuroma is another type of tumor that has also been associated with autonomic dysfunction (Gentile, Rainero, Luda & Pinessi, 2001). Tumors can cause compression, which directly affects the autonomic nervous system. Tumors are also capable of having a paraneoplastic effect on the ANS by producing autoantibodies against acetylcholine receptors in the autonomic ganglia (Grubb, Kanjwal & Kosinski, 2006). Thyroid disease can cause symptoms that are similar to those of POTS. Viruses are thought to be the provoking factor in approximately 50% of POTS patients (Low & Schondorf, 1997, p. 279). There are reports of dysautonomia occurring after the Epstein-Barr virus (Itoh, Oishi, Ohnishi, Murai & Imawatari, 1993). Viruses may directly affect the autonomic nervous system or lead to an immune pathogenesis (Grubb, 2000). Roughly one-half of post-viral POTS patients will make a good practical recovery over a 2-5 year period (Grubb, Kanjwal & Kosinski, 2006). These are but a few of the possible causes of POTS symptoms. More information on causes of autonomic dysfunction can be located at the National Dysautonomia Research Foundation. References 1. Autonomic Dysfunction. (2000). The WorldWide Anaesthetist. http://anaesthetist.com/anaes/patient/ans.htm 2. Bernstein, R. S., Pierson, R. N. 3rd., Ryan, S. F., & Crespin S. B. (1979). Adipose cell morphology and control of lipolysis in a patient with partial lipodystrophy. Metabolism, 28, 519-526. PMID: 449692 [PubMed - indexed for MEDLINE] 3. Carson, R. P., Appalsamy, M., Diedrich, A., Davis, T. L., & Robertson, D. (2001). Animal model of neuropathic tachycardia syndrome. Hypertension, 37, 1357-1361. Full text: http://hyper.ahajournals.org/cgi/content/full/37/6/1357 4. Esler M., Alvarenga M., Pier C., Richards J., El-Osta A., Barton D., Haikerwal D., Kaye D., Schlaich M., Guo L., Jennings G., Socratous F., & Lambert G. (2006). The neuronal noradrenaline transporter, anxiety and cardiovascular disease. J Psychopharmacol. Jul;20(4 Suppl):60-6. PubMed 5. Gazit, Y., Nahir, A. M., Grahame, R., & Jacob, G. (2003). Dysautonomia in the joint hypermobility syndrome. The American Journal of Medicine. 115(1), 33-40. PubMed 6. Gentile, S., Rainero, I., Luda, E., & Pinessi, L. (2001). Autonomic dysfunction associated with multiple pelvic ganglioneuromas. Acta Neurologica Scandinavica, 104(1), 54-56. PMID: 11442444 [PubMed - indexed for MEDLINE] 7. Gibbons C. H. & Freeman R. (2009). Antibody titers predict clinical features of autoimmune autonomic ganglionopathy. Auton Neurosci. 12;146(1-2), 8-12. PubMed. 8. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 9. Grubb, B. P. (2002, October). The heterogeneity of symptoms related to dysautonomia. Symposium conducted at the meeting of the National Dysautonomia Research Foundation Northwest Ohio Support Group. Toledo, Ohio. 10. Grubb B. P., Kanjwal, Y., & Kosinski, D. J. (2006). The postural tachycardia syndrome: A concise guide to diagnosis and management. J Cardiovasc Electrophysiol., 17, 108-112. 11. Grubb, B. P., & Karas, B. (1999). Clinical disorders of the autonomic nervous system associated with orthostatic intolerance. Pacing and Clinical Electrophysiology, 22, 798-810. Full text: http://www.ndrf.org/PDF%20Files/disorders.PDF 12. Haensch, C. A., Lerch, H., Schlemmer, H., Jigalin, A., & Isenmann, S. (2009). Cardiac Neurotransmission Imaging with 123I-Meta-iodobenzylguanidine in Postural Tachycardia Syndrome. J Neurol Neurosurg Psychiatry. 2009 Aug 16. PubMed 13. Hakim, A. J., & Grahame, R. (2004). Letters to the editor: Non-musculoskeletal symptoms in joint hypermobility syndrome. Indirect evidence for autonomic dysfunction? Rheumatology. 43, 1194-1195. Full Text 14. Hartleb, M., Rudzki, K., Karpel, E., Becker, A., Waluga, M., Boldys, H., Nowak, A., & Nowak, S. (1979). Cardiovascular status after postural change in compensated cirrhosis: an argument for vasodilatory concept. Liver, 17(1), 1-6. PMID: 9062872 [PubMed - indexed for MEDLINE] 15. Healthline Scripts: Cardiac Atrophy. (1998). National Space Biomedical Research Institute. 16. Itoh, Y., Oishi, T., Ohnishi, A., Murai, Y., & Imawatari, R. (1993). [Acute cerebellar ataxia with sympathotonic orthostatic hypotension following Epstein-Barr virus infection--a case report]. Rinsho Shinkeigaku, 33, 503-506. PMID: 8395987 [PubMed - indexed for MEDLINE] 17. Jacob, G., & Biaggioni I. (1999). Idiopathic orthostatic intolerance and postural tachycardia syndromes. The American Journal of the Medical Sciences, 317, 88-101. PMID: 10037112 [PubMed - indexed for MEDLINE] 18. Kanjwal, K., Karabin, B., Kanjwal, Y., & Grubb, B.P. (2009). Postural orthostatic tachycardia syndrome: a rare complication following electrical injury. Pacing and Clinical Electrophysiology. Dec 10. 19. Llamas, E. G., Garcia, R. G., Gaos, C. Jr., Jimenez, J. L., Villavicencio, R., Cueto, L., & Arriaga, G. J. (1985). Cardiac autonomic neauropathy in the diabetic patient. Archivos del Instituto de Cardiologia de Mexico, 55, 247-256. Spanish. PMID: 2932078 [PubMed - indexed for MEDLINE] 20. Low, P. A., Schondorf, R. (1996). Postural tachycardia syndrome. In D. Robertson, P. A. Low & R. J. Polinsky (Eds.), Primer on the autonomic nervous system (p. 279). San Diego, CA: Academic Press. 21. Mitka, M. (2002). Returning astronaut study helps some reeling patients. The Journal of the American Medical Association, 287, 837. 22. Nand, N., Mohan R., Khosla, S. N., & Kumar P. (1989). Autonomic function tests in cases of chronic severe anaemia. Journal of the Association of Physicians of India, 37, 508-510. PMID: 2621185 [PubMed - indexed for MEDLINE] 23. NINDS Syringomyelia Information Page. (2001). National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/syringomyelia/syringomyelia.htm 24. Raj, S. R., Biaggioni, I., Yamhure, P. C., Black, B. K., Paranjape, S. Y., Byrne, D. W., & Robertson, D. (2005). Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Circulation. 111(13), 1574-1582. 25. Rosner, M. J., D'Amour, P., & Rowe, P. C. (1999, September). Neurally Mediated Hypotension: its Surgical Evaluation, Management and Early Outcome as Part of the Fibromyalgia—Chronic Fatigue Syndrome. National Fibromyalgia Research Association's Subgroups in Fibromyalgia Symposium. Portland, Oregon. http://www.nfra.net/SubRosner2.htm 26. Rowe, P. C., Barron, D. F., Calkins, H., Maumenee, I. H., Tong, P. Y., & Geraghty, M. T. (1999). Orthostatic intolerance and chronic fatigue syndrome associated with Ehlers-Danlos syndrome. Journal of Pediatrics, 135, 494-499. PMID: 10518084 [PubMed - indexed for MEDLINE] 27. Shen, W. K. (2002). Modification and ablation for inappropriate sinus tachycardia: current status. Cardiac Electrophysiology Review. 6(4), 349-355. PubMed 28. Shen, W. K., Low, P.A., Jahangir, A., Munger, T. M., Friedman, P. A., Osborn, M. J., Stanton, M. S., Packer, D. L., Rea, R. F., Hammill, S. C. (2001). Is sinus node modification appropriate for inappropriate sinus tachycardia with features of postural orthostatic tachycardia syndrome? Pacing & Clinical Electrophysiology, 24(2), 217-230. PubMed 29. Singer, W., Shen, W. K., Opfer-Gehrking, T.L., McPhee, B. R., Hilz, M. J., & Low, P.A. (2002). Evidence of an intrinsic sinus node abnormality in patients with postural tachycardia syndrome. Mayo Clinic Proceedings, 77, 246-252. 30. Singer, W., Shen, W. K., Opfer-Gehrking, T.L., McPhee, B. R., Hilz, M. J., & Low, P.A. (2003). Heart rate-dependent electrocardiogram abnormalities in patients with postural tachycardia syndrome. Autononomic Neuroscience, 31, 103(1-2), 106-113. PMID: 12531404 [PubMed - in process] 31. Singh, N. K., Jaiswal, A. K., Misra, S., & Srivastava, P. K. (1987). Assessment of autonomic function in Guillain-Barre syndrome and its prognostic implications. Acta Neurologica Scandinavica, 75, 101-105. PMID: 3577674 [PubMed -indexed for MEDLINE] 32. Steinmann, B., Royce, P. M., Superti-Furga, A. (1993). The Ehlers-Danlos syndrome. In: P. M. Royce & B. Steinman (Eds), Connective tissue and its heritable disorders (pp. 351-408).New York: Wiley-Liss, Inc. 33. Stewart, J. M. Local vasoconstriction in postural tachycardia syndrome. Retrieved April 19, 2005, from Center for Pediatric Hypotension. 34. Stewart, J. M., Ocon, A. J., Clarke, D., Taneja, I., Medow, M. S. (2009). Defects in cutaneous angiotensin-converting enzyme 2 and angiotensin-(1-7) production in postural tachycardia syndrome. Hypertension. 53(5), 767-774. PubMed 35. Stewart, J. M., Taneja, I., Glover, J., & Medow, M. S. (2008). Angiotensin II type 1 receptor blockade corrects cutaneous nitric oxide deficit in postural tachycardia syndrome. American Journal of Physiology. Heart and Circulatory Physiology. 294(1), H466-73. PubMed 36. Stewart, P. M., & Hensley, W. J. (1981). An acute attack of variegate porphyria complicated by severe autonomic neuropathy. Australian and New Zealand Journal of Medicine, 11(1), 82-83. PMID: 6941785 [PubMed - indexed for MEDLINE] 37. Takahashi, Y., Ohta, S., Sano, A., Kuroda, Y., Kaji, Y., Matusuki, M., & Matsuo, M. (2000). Does severe nutcracker phenomenon cause pediatric chronic fatigue? Clinical Nephrology, 53, 174-181. PMID: 10749295 [PubMed - indexed for MEDLINE] 38. Takahashi, Y., Sano, A., Matsuo, M. (2000). An effective "transluminal balloon angioplasty" therapy for pediatric chronic fatigue syndrome with nutcracker phenomenon. Clinical Nephrology, 53, 77-78. PMID: 10661488 [PubMed - indexed for MEDLINE] 39. Wenstrup, R. J., & Hoechstetter, L. B. (2001). The Ehlers-Danlos syndromes. In S. B. Cassidy & J. E. Allanson (Eds.) , Management of genetic syndromes (pp. 131-149). New York: Wiley-Liss, Inc. 40. Vernino, S., Low, P. A., Fealey, R. D., Stewart, J. D., Farrugia, G., & Lennon, V. A. (2000). Autoantibodies to Ganglionic Acetylcholine Receptors in Autoimmune Autonomic Neuropathies. The New England Journal of Medicine, 343, 847-855. http://content.nejm.org/cgi/content/abstract/343/12/847

There are identifiable mechanisms that can be contributing to a patient's orthostatic intolerance. Many of these mechanisms may result in a lack of oxygen to the brain upon standing. Blood pooling in the veins of the lower body is a major factor in the vast majority of patients with orthostatic intolerance (Streeten, 1999). The following is a partial list of proposed mechanisms that may be occurring in patients with orthostatic intolerance: Alpha-receptor dysfunction may be occurring in some POTS patients (Gordon, Opfer-Gehrking, Novak & Low, 2000). Alpha-1 receptors cause peripheral vasoconstriction when stimulated. Alpha-1 receptor supersensitivity may be causing dysautonomia in some patients (Stewart & Erickson, 2002). Others with POTS may have an autonomic neuropathy that predominantly affects the lower extremities. This neuropathy may be resulting in alpha-1 adrenergic denervation hypersensitivity. Denervation hypersensitivity may be provoking the pooling of blood in a number of individuals with this disorder (Stewart & Erickson, 2002). Beta-receptor supersensitivity may occur with hyperadrenergic states in some people with POTS (Low, 2000). The heart is responding to excessive catecholamine output in these patients. Brain-stem dysregulation may be occurring in some POTS patients (Novak, Novak, Opfer-Gehrking, O'Brien & Low, 1998). Researchers have identified a subset of patients with marked orthostatic hypertension, markedly labile blood pressure and troublesome orthostatic symptoms (Low, Schondorf, Novak, Sandroni, Opfer-Gehrking & Novak, 1997, pp. 686-687). These patients present as though they are suffering from baroreflex failure, although the baroreflexes are working. Excessive sympathetic activity is noted, which suggests the possibility of central (presumably brain-stem) dysregulation. One patient reportedly improved after microvascular decompression at the region of the left medulla (Low et al., 1997, p. 687). Central autonomic regulation abnormalities leading to a hyperadrenergic state are a proposed cause of POTS. However, physicians have yet to determine whether a central abnormality of the autonomic nervous system is the primary mechanism or if the increase in sympathetic activity is an appropriate response to an underlying defect, such as a decreased blood volume or a circulating vasodilator (Jacob & Biaggioni, 1999). Circulating vasodilators are suspected of provoking dysautonomia in disorders such as hyperbradykininism, mast-cell activation and hyperdopaminergic states. Delayed forms of orthostatic intolerance have been observed in POTS patients. Some physicians believe POTS symptoms should occur within 10 minutes of standing. However, studies on orthostatic intolerant patients prove that some display a delayed form of orthostatic intolerance in which orthostatic hypotension occurs after ten minutes of standing (Streeten & Anderson, 1992). One study showed that out of 23 chronic fatigue patients, 17 had orthostatic tachycardia alone during the initial period of head-up tilt. However, 22 eventually had obvious orthostatic hypotension after an extended period of time (Bou-Holaigah, Rowe, Kan & Calkins, 1995). Hyperdopaminergic states maybe the underlying problem for some people with orthostatic intolerance. Some patients have been found to have a significant increase in upright (free + sulfconjugated) dopamine levels (Kuchel, Buu, Hamet, Larochelle, Gutkowska, Schiffrin, Bourque & Genest, 1985). Free plasma norepinephrine also tends to be higher in these patients. The excessive dopamine release might be causing natriuresis and vasodilatation, thus contributing to the pathophysiology of this disorder (Jacob & Biaggioni, 1999). Orthostatic hypotension occurs in some patients with orthostatic intolerance. However, there are physicians who exclude orthostatic hypotension when defining POTS. Orthostatic hypotension is traditionally defined as a fall in systolic blood pressure of 20 mm Hg or more upon standing. Some physicians believe smaller drops in blood pressure associated with symptoms are also significant (Grubb & Karas, 1999). Orthostatic hypotension may become apparent only after prolonged standing. Baroreceptor-initiated reflex tachycardia is a potent physiological mechanism for correcting hypotension (Streeten, 1999). Hence, the standing tachycardia observed in POTS patients is sometimes occurring because the body is attempting to counteract falling blood pressure. Some patients become more symptomatic than others when their blood pressure drops. Patients who experience few symptoms while hypotensive have a minimal decline in brain blood flow and good dilating blood vessels. Patients who become symptomatic when their blood pressure drops have a greater decline in blood flow to the brain (Coghlan, 2002). Reduced cerebral blood flow has been noted in several studies of POTS patients. However, one studydid not report this finding, and concluded that cerebral perfusion and autoregulation in many patients with POTS does not differ from that of normal control subjects (Schondorf, Benoit & Stein, 2005). A reduction of cardiac output by arrhythmias, bradycardia, or intrinsic cardiac causes of pump failure can cause fainting, or other clinical manifestations of reduced cerebral blood flow (Streeten, 1999). Blood pooling in the lower body may also cause reduced blood flow to the brain. It has been reported that a person with POTS can have a 28% decrease in brain blood flow upon standing (Robertson, 2000). A normal person will have about a 9% decrease in blood flow to the brain upon standing. Transcranial Doppler ultrasonography is useful in detecting a reduction in cerebral blood flow (Fredman, Biermann, Patel, Uppstrom & Auer, 1995). Orthostatic symptoms have been attributed to impaired cerebral perfusion, even in the absence of a significant fall in blood pressure (Jacob & Biaggioni, 1999). Central nervous system abnormalities may be occurring in patients with reduced cerebral blood flow (Hermosillo, Jauregui-Renaud, Kostine, Marquez, Lara & Cardenas, 2002). One study reported that continuous observation of the Doppler recording in patients with postural tachycardia showed intermittent fluctuation of the cerebral blood flow velocity, with an oscillatory pattern (Hermosillo et al., 2002). This fluctuation in cerebral blood flow velocity occurred in spite of there being no systemic hypotension. This study also showed that when compared with neurocardiogenic syncope patients, those with postural tachycardia had larger variations of the pulsatility index (systolic velocity-diastolic velocity/mean velocity). The results suggest that patients with postural tachycardia, on standing up, could have an inefficient regulation of cerebral blood vessels (Hermosillo, et al., 2002). These findings led the researchers to conclude that central nervous system abnormalities may play a pivotal role in the pathogenesis of postural tachycardia syndrome (Hermosillo, et al., 2002). Reduced venous return is one of the main mechanisms that results in POTS symptoms. Venous return can be reduced due to conditions such as low plasma volume (see hypovolemia), venous pooling and denervation (Low, 2000). A hyperadrenergic state may result as the body attempts to compensate for these abnormalities. Conditions resulting in reduced venous return often overlap or occur because of one another. The following are some abnormalities that can result in reduced venous return: Abnormal veins that stretch excessively can result in pooling blood (Stewart, 2000). Altered capillary permeability can affect capillary leakiness and cause excessive fluid collection in the lower body (Stewart, 2000). This may be contributing to orthostatic intolerance in a number of POTS patients. Blood vessels that don't seem to constrict appropriately have been noted in POTS patients. Some physicians believe this subnormal orthostatic venous constriction, resulting from impaired sympathetic innervation, is the cause of blood pooling excessively in the legs of POTS patients (Streeten, 1999). This loss in the ability to vasoconstrict leads to excessive heart rate increases and contractions (Grubb, 2000). Denervation occurs in some POTS patients. A number of patients do not sweat in various parts of their bodies. Some patients report losing their ability to sweat altogether. This lack of sweating shows that the nerve supply to the area is damaged (Low, 2000). As a result, the vessels that the nerve supplies lose their tone and become slack. Blood volume is normal but vessel capacity is excessive (Low, 2000). This causes decreased venous return of blood flow to the heart, decreased cardiac output and (probably) orthostatic reduction in cerebral blood flow (Streeten, 1999). Peripheral neuropathy may be present in these patients. This neuropathy seems to be selective, with slight responses in some regions being compensated for by overactivity in other regions (Bush, Wight, Brown & Hainsworth, 2000). Hypovolemia (low blood volume) sometimes occurs in POTS patients. The patients may have a reduced blood volume throughout their body, or the hypovolemia may occur due to blood pooling in the abdomen and legs. Reduced plasma renin activity often accompanies the low blood volume. Reduced levels of renin release consequently result in reduced secretion of aldosterone. This would be expected to impair renal sodium conservation thereby contributing to hypovolemia (Streeten, 1999). Findings suggest that the impaired renin release may possibly result from sympathetic denervation (Jacob & Biaggioni, 1999). Abnormalities in the kidney are also suspected of causing the reduced renin and aldosterone levels (Raj, Biaggioni, Yamhure, Black, Paranjape, Byrne & Robertson, 2005). Physicians believe hypovolemia and inappropriately low levels of plasma renin activity may be important pathophysiological components of orthostatic intolerance (Jacob, Robertson, Mosqueda-Garcia, Ertl, Robertson & Biaggioni, 1997). Decreases in body temperature may result from hypovolemia (Heitz & Horne, 2005, 35). The findings in hypovolemic POTS patients have been dubbed the "renin-aldosterone paradox" and are explained as follows: Under normal circumstances, low plasma volume is sensed in the kidney (and in the heart and aorta) and stimulates an increase in plasma renin activity (renin), angiotensin II (A-II), and aldosterone (ALDO). The increase in plasma renin activity and aldosterone promotes salt and water retention, which leads to an increase in extracellular fluid volume and plasma volume. In POTS, there is a failure to sense and appropriately respond to low plasma volume. There is no appropriate increase in plasma renin activity, angiotensin II, and aldosterone given the hypovolemia. Because plasma renin activity and aldosterone are not increased, salt and water retention is not increased, and plasma volume is not increased (Raj, et. al., 2005). Erythropoietin response impairment may be contributing to a patient's hypovolemia. Erythropoietin is a hormone made by the kidneys. It helps stimulate red blood cell production. Impairment of the normal erythropoietin response to low levels of red blood cell mass could contribute to hypovolemia. Physicians postulate that subnormal erythropoietin response may be resulting from a disorder in the normal sympathetic stimulation of erythropoietin release by the kidney (Streeten, 1999). Read more Paradoxically, POTS can occur because of hypovolemia or hypovolemia can occur because of POTS. This can happen because hypovolemia may lead to a chronic state of adrenergic activation, which may produce POTS symptoms. Chronic adrenergic activation reduces intravascular volume, which may produce hypovolemia (Stewart & Erickson, 2002). Read more Impaired venous emptying can cause excessive fluid collection in the lower body. This can lead to blood pooling in the lower limbs and consequently, orthostatic intolerance. Splanchnic pooling is occurring after meals in some POTS patients. Excessive pooling of blood in the abdomen has been shown to occur while the patient is supine and at rest (Tani, Singer, McPhee, Opfer-Gehrking, Haruma, Kajiyama & Low, 2000). The splanchnic vascular bed contains up to 30% of blood volume. Limited autonomic neuropathy causing peripheral denervation may be the cause of increased resting flow and reduced mesenteric resistance in these patients. Sympathetic Overactivity is observed in many POTS patients. The sympathetic overactivity can be secondary to a number of factors, some of which may be peripheral denervation, venous pooling, or end-organ dysfunction (Low et al, 1998). Hyperadrenergic states with elevated norepinephrine levels are often found in patients with sympathetic overactivity. One study found that 29% of POTS patients had elevated norepinephrine levels upon standing, and the mean level was 531 pg/mL (Thieben, Sandroni, Sletten, Benrud-Larson, Fealey, Vernino, Lennon, Shen & Low, 2007). Norepinephrine is similar to adrenaline and is a natural vasoconstrictor. Genetic or acquired deficits in norepinephrine activation may result in hyperadrenergic states that lead to orthostatic intolerance (Shannon, Flattem, Jordan, Jacob, Black, Biaggioni, Blakely & Robertson, 2000). These deficits can cause patients to experience symptoms suggestive of not enough norepinephrine simultaneously with high norepinephrine levels. Many of the mechanisms listed here can result in states of chronic adrenergic activation that lead to orthostatic intolerance. Sympathetic underactivty can also occur in some forms of orthostatic intolerance (Robertson, 2000), such as pure autonomic failure. The above are some of the possible mechanisms that may be resulting in orthostatic intolerance. Physicians should attempt to discover the underlying mechanisms contributing to a patient's symptoms. This will ensure that treatment plans are tailored to target the specific mechanisms resulting in autonomic dysfunction, and that patients will receive the most effective care. References 1. Bou-Holaigah, I., Rowe, P. C., Kan, J., & Calkins, H. (1995). The relationship between neurally mediated hypotension and the chronic fatigue syndrome. Journal of the American Medical Association, 27, 961-967. PMID: 7674527 [PubMed - indexed for MEDLINE] 2. Bush, V. E., Wight, V. L., Brown, C. M., & Hainsworth, R. (2000). Vascular responses to orthostatic stress in patients with postural tachycardia syndrome (POTS), in patients with low orthostatic tolerance, and in asymptomatic controls. Clinical Autonomic Research 10, 279-284. PMID: 11198483 [PubMed - indexed for MEDLINE] 3. Coghlan, H. C. (2002, July). Orthostatic Intolerance. National Dysautonomia Research Foundation Patient Conference. Washington, DC. 4. Fredman, C. S., Biermann, K. M., Patel, V., Uppstrom, E. L., & Auer, A. I. (1995). Transcranial Doppler Ultrasonography during Head-Upright Tilt-Table Testing. Annals of Internal Medicine 123, 848-849. 5. Gordon, V. M., Opfer-Gehrking, T. L., Novak, V., & Low, P. A. (2000). Hemodynamic and symptomatic effects of acute interventions on tilt in patients with postural tachycardia syndrome. Clinical Autonomic Research, 10(1), 29-33. PMID: 10750641 6. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 7. Grubb, B. P., & Karas, B. (1999) Clinical disorders of the autonomic nervous system associated with orthostatic intolerance. Pacing and Clinical Electrophysiology, 22, 798-810. Full text: http://www.ndrf.org/PDF%20Files/disorders.PDF 8. Heitz, U. & Horne, M. M. (2005). Fluid, Electrolyte and Acid-Base Balance. St. Louis, MO: Elsevier Mosby. 9.Hermosillo, A. G., Jauregui-Renaud, K., Kostine, A., Marquez, M. F., Lara, J. L., Cardenas, M. (2002). Comparative study of cerebral blood flow between postural tachycardia and neurocardiogenic syncope, during head-up tilt test. Europace, 4, 369-74. Full text: http://europace.oxfordjournals.org/cgi/reprint/4/4/369 .10. Jacob, G., & Biaggioni I. (1999). Idiopathic orthostatic intolerance and postural tachycardia syndromes. The American Journal of the Medical Sciences, 317, 88-101. PMID: 10037112 11. Jacob, G., Robertson, D., Mosqueda-Garcia, R., Ertl, A. C., Robertson, R. M., Biaggioni, I. (1997). Hypovolemia in syncope and orthostatic intolerance: role of the renin-angiotensin system. American Journal of Medicine, 103(2), 128-133. PMID: 9274896 12. Kuchel, O., Buu, N. T., Hamet, P., Larochelle, P., Gutkowska, J., Schiffrin, E. L., Bourque, M., & Genest, J. (1985). Orthostatic hypotension: a posture-induced hyperdopaminergic state. The American Journal of the Medical Sciences, 289, 3-11. PMID: 3881951 13. Low, P. A. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 14. Low, P. A., Schondorf, R., Novak, V., Sandroni, P., Opfer-Gehrking, T. L., & Novak, P. (1997). Postural Tachycardia Syndrome. In P.A. Low (Ed.), Clinical Autonomic Disorders (pp. 681-697). Philadelphia: Lippincott-Raven Publishers. 15. Novak, V., Novak, P., Opfer-Gehrking, T. L., O'Brien, P. C., & Low P. A. (1998). Clinical and laboratory indices that enhance the diagnosis of postural tachycardia syndrome. Mayo Clinic Proceedings, 73, 1141-50. PMID: 9868411 [PubMed - indexed for MEDLINE] 16. Raj, S. R., Biaggioni, I., Yamhure, P. C., Black, B. K., Paranjape, S. Y., Byrne, D. W., & Robertson, D. (2005). Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Circulation. 111(13), 1574-1582. Full Text 17. Robertson, D. (2000, July). General description of the autonomic nervous system and orthostatic intolerance overview. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 18. Schondorf, R., Benoit, J., & Stein, R. (2005). Cerebral autoregulation is preserved in postural tachycardia syndrome (POTS). Journal of Applied Physiology, Apr 28; [Epub ahead of print] Full Text 19. Shannon, J. R., Flattem, N. L., Jordan, J., Jacob, G., Black, B. K., Biaggioni, I., Blakely, R. D., & Robertson, D. (2000). Orthostatic intolerance and tachycardia associated with norepinephrine-transporter deficiency. New England Journal of Medicine, 24, 541-9. http://content.nejm.org/cgi/content/abstract/342/8/541 20. Stewart, J. M. (2000, July). Pediatric and adolescent orthostatic intolerance and CFIDS. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 21. Stewart, J. M., & Erickson, L.C., (2002). Orthostatic intolerance: an overview. In Alejos, J. C., Konop, R., Chin, A. J., Herzberg, G., Neish, S. (Eds.). emedicine Journal, 3, (1). http://www.emedicine.com/ped/topic2860.htm 22. Stewart, J. M., & Weldon, A. (2001). Reflex vascular defects in the orthostatic tachycardia syndrome of adolescents. Journal of Applied Physiology, 90, 2025-2032. Full text: http://jap.physiology.org/cgi/content/full/90/6/2025 23. Streeten, D. H. (1999). Orthostatic intolerance. A historical introduction to the pathophysiological mechanisms. The American Journal of the Medical Sciences, 317, 78-87. PMID: 10037111 24. Streeten, D. H., & Anderson, G. H. (1992). Delayed orthostatic intolerance. Archives of Internal Medicine, 152, 1066-72 PMID: 1580710 [PubMed - indexed for MEDLINE] 25. Thieben, M. J., Sandroni, P., Sletten, D. N., Benrud-Larson, L. M., Fealey, R. D., Vernino, S., Lennon, V. A., Shen, W. K., & Low, P. A., (2007). Postural orthostatic tachycardia syndrome: the Mayo Clinic experience. Mayo Clin. Proc. 82, (3), 308-313.

There are identifiable mechanisms that can be contributing to a patient's orthostatic intolerance. Many of these mechanisms may result in a lack of oxygen to the brain upon standing. Blood pooling in the veins of the lower body is a major factor in the vast majority of patients with orthostatic intolerance (Streeten, 1999). The following is a partial list of proposed mechanisms that may be occurring in patients with orthostatic intolerance: Alpha-receptor dysfunction may be occurring in some POTS patients (Gordon, Opfer-Gehrking, Novak & Low, 2000). Alpha-1 receptors cause peripheral vasoconstriction when stimulated. Alpha-1 receptor supersensitivity may be causing dysautonomia in some patients (Stewart & Erickson, 2002). Others with POTS may have an autonomic neuropathy that predominantly affects the lower extremities. This neuropathy may be resulting in alpha-1 adrenergic denervation hypersensitivity. Denervation hypersensitivity may be provoking the pooling of blood in a number of individuals with this disorder (Stewart & Erickson, 2002). Beta-receptor supersensitivity may occur with hyperadrenergic states in some people with POTS (Low, 2000). The heart is responding to excessive catecholamine output in these patients. Brain-stem dysregulation may be occurring in some POTS patients (Novak, Novak, Opfer-Gehrking, O'Brien & Low, 1998). Researchers have identified a subset of patients with marked orthostatic hypertension, markedly labile blood pressure and troublesome orthostatic symptoms (Low, Schondorf, Novak, Sandroni, Opfer-Gehrking & Novak, 1997, pp. 686-687). These patients present as though they are suffering from baroreflex failure, although the baroreflexes are working. Excessive sympathetic activity is noted, which suggests the possibility of central (presumably brain-stem) dysregulation. One patient reportedly improved after microvascular decompression at the region of the left medulla (Low et al., 1997, p. 687). Central autonomic regulation abnormalities leading to a hyperadrenergic state are a proposed cause of POTS. However, physicians have yet to determine whether a central abnormality of the autonomic nervous system is the primary mechanism or if the increase in sympathetic activity is an appropriate response to an underlying defect, such as a decreased blood volume or a circulating vasodilator (Jacob & Biaggioni, 1999). Circulating vasodilators are suspected of provoking dysautonomia in disorders such as hyperbradykininism, mast-cell activation and hyperdopaminergic states. Delayed forms of orthostatic intolerance have been observed in POTS patients. Some physicians believe POTS symptoms should occur within 10 minutes of standing. However, studies on orthostatic intolerant patients prove that some display a delayed form of orthostatic intolerance in which orthostatic hypotension occurs after ten minutes of standing (Streeten & Anderson, 1992). One study showed that out of 23 chronic fatigue patients, 17 had orthostatic tachycardia alone during the initial period of head-up tilt. However, 22 eventually had obvious orthostatic hypotension after an extended period of time (Bou-Holaigah, Rowe, Kan & Calkins, 1995). Hyperdopaminergic states maybe the underlying problem for some people with orthostatic intolerance. Some patients have been found to have a significant increase in upright (free + sulfconjugated) dopamine levels (Kuchel, Buu, Hamet, Larochelle, Gutkowska, Schiffrin, Bourque & Genest, 1985). Free plasma norepinephrine also tends to be higher in these patients. The excessive dopamine release might be causing natriuresis and vasodilatation, thus contributing to the pathophysiology of this disorder (Jacob & Biaggioni, 1999). Orthostatic hypotension occurs in some patients with orthostatic intolerance. However, there are physicians who exclude orthostatic hypotension when defining POTS. Orthostatic hypotension is traditionally defined as a fall in systolic blood pressure of 20 mm Hg or more upon standing. Some physicians believe smaller drops in blood pressure associated with symptoms are also significant (Grubb & Karas, 1999). Orthostatic hypotension may become apparent only after prolonged standing. Baroreceptor-initiated reflex tachycardia is a potent physiological mechanism for correcting hypotension (Streeten, 1999). Hence, the standing tachycardia observed in POTS patients is sometimes occurring because the body is attempting to counteract falling blood pressure. Some patients become more symptomatic than others when their blood pressure drops. Patients who experience few symptoms while hypotensive have a minimal decline in brain blood flow and good dilating blood vessels. Patients who become symptomatic when their blood pressure drops have a greater decline in blood flow to the brain (Coghlan, 2002). Reduced cerebral blood flow has been noted in several studies of POTS patients. However, one studydid not report this finding, and concluded that cerebral perfusion and autoregulation in many patients with POTS does not differ from that of normal control subjects (Schondorf, Benoit & Stein, 2005). A reduction of cardiac output by arrhythmias, bradycardia, or intrinsic cardiac causes of pump failure can cause fainting, or other clinical manifestations of reduced cerebral blood flow (Streeten, 1999). Blood pooling in the lower body may also cause reduced blood flow to the brain. It has been reported that a person with POTS can have a 28% decrease in brain blood flow upon standing (Robertson, 2000). A normal person will have about a 9% decrease in blood flow to the brain upon standing. Transcranial Doppler ultrasonography is useful in detecting a reduction in cerebral blood flow (Fredman, Biermann, Patel, Uppstrom & Auer, 1995). Orthostatic symptoms have been attributed to impaired cerebral perfusion, even in the absence of a significant fall in blood pressure (Jacob & Biaggioni, 1999). Central nervous system abnormalities may be occurring in patients with reduced cerebral blood flow (Hermosillo, Jauregui-Renaud, Kostine, Marquez, Lara & Cardenas, 2002). One study reported that continuous observation of the Doppler recording in patients with postural tachycardia showed intermittent fluctuation of the cerebral blood flow velocity, with an oscillatory pattern (Hermosillo et al., 2002). This fluctuation in cerebral blood flow velocity occurred in spite of there being no systemic hypotension. This study also showed that when compared with neurocardiogenic syncope patients, those with postural tachycardia had larger variations of the pulsatility index (systolic velocity-diastolic velocity/mean velocity). The results suggest that patients with postural tachycardia, on standing up, could have an inefficient regulation of cerebral blood vessels (Hermosillo, et al., 2002). These findings led the researchers to conclude that central nervous system abnormalities may play a pivotal role in the pathogenesis of postural tachycardia syndrome (Hermosillo, et al., 2002). Reduced venous return is one of the main mechanisms that results in POTS symptoms. Venous return can be reduced due to conditions such as low plasma volume (see hypovolemia), venous pooling and denervation (Low, 2000). A hyperadrenergic state may result as the body attempts to compensate for these abnormalities. Conditions resulting in reduced venous return often overlap or occur because of one another. The following are some abnormalities that can result in reduced venous return: Abnormal veins that stretch excessively can result in pooling blood (Stewart, 2000). Altered capillary permeability can affect capillary leakiness and cause excessive fluid collection in the lower body (Stewart, 2000). This may be contributing to orthostatic intolerance in a number of POTS patients. Blood vessels that don't seem to constrict appropriately have been noted in POTS patients. Some physicians believe this subnormal orthostatic venous constriction, resulting from impaired sympathetic innervation, is the cause of blood pooling excessively in the legs of POTS patients (Streeten, 1999). This loss in the ability to vasoconstrict leads to excessive heart rate increases and contractions (Grubb, 2000). Denervation occurs in some POTS patients. A number of patients do not sweat in various parts of their bodies. Some patients report losing their ability to sweat altogether. This lack of sweating shows that the nerve supply to the area is damaged (Low, 2000). As a result, the vessels that the nerve supplies lose their tone and become slack. Blood volume is normal but vessel capacity is excessive (Low, 2000). This causes decreased venous return of blood flow to the heart, decreased cardiac output and (probably) orthostatic reduction in cerebral blood flow (Streeten, 1999). Peripheral neuropathy may be present in these patients. This neuropathy seems to be selective, with slight responses in some regions being compensated for by overactivity in other regions (Bush, Wight, Brown & Hainsworth, 2000). Hypovolemia (low blood volume) sometimes occurs in POTS patients. The patients may have a reduced blood volume throughout their body, or the hypovolemia may occur due to blood pooling in the abdomen and legs. Reduced plasma renin activity often accompanies the low blood volume. Reduced levels of renin release consequently result in reduced secretion of aldosterone. This would be expected to impair renal sodium conservation thereby contributing to hypovolemia (Streeten, 1999). Findings suggest that the impaired renin release may possibly result from sympathetic denervation (Jacob & Biaggioni, 1999). Abnormalities in the kidney are also suspected of causing the reduced renin and aldosterone levels (Raj, Biaggioni, Yamhure, Black, Paranjape, Byrne & Robertson, 2005). Physicians believe hypovolemia and inappropriately low levels of plasma renin activity may be important pathophysiological components of orthostatic intolerance (Jacob, Robertson, Mosqueda-Garcia, Ertl, Robertson & Biaggioni, 1997). Decreases in body temperature may result from hypovolemia (Heitz & Horne, 2005, 35). The findings in hypovolemic POTS patients have been dubbed the "renin-aldosterone paradox" and are explained as follows: Under normal circumstances, low plasma volume is sensed in the kidney (and in the heart and aorta) and stimulates an increase in plasma renin activity (renin), angiotensin II (A-II), and aldosterone (ALDO). The increase in plasma renin activity and aldosterone promotes salt and water retention, which leads to an increase in extracellular fluid volume and plasma volume. In POTS, there is a failure to sense and appropriately respond to low plasma volume. There is no appropriate increase in plasma renin activity, angiotensin II, and aldosterone given the hypovolemia. Because plasma renin activity and aldosterone are not increased, salt and water retention is not increased, and plasma volume is not increased (Raj, et. al., 2005). Erythropoietin response impairment may be contributing to a patient's hypovolemia. Erythropoietin is a hormone made by the kidneys. It helps stimulate red blood cell production. Impairment of the normal erythropoietin response to low levels of red blood cell mass could contribute to hypovolemia. Physicians postulate that subnormal erythropoietin response may be resulting from a disorder in the normal sympathetic stimulation of erythropoietin release by the kidney (Streeten, 1999). Read more Paradoxically, POTS can occur because of hypovolemia or hypovolemia can occur because of POTS. This can happen because hypovolemia may lead to a chronic state of adrenergic activation, which may produce POTS symptoms. Chronic adrenergic activation reduces intravascular volume, which may produce hypovolemia (Stewart & Erickson, 2002). Read more Impaired venous emptying can cause excessive fluid collection in the lower body. This can lead to blood pooling in the lower limbs and consequently, orthostatic intolerance. Splanchnic pooling is occurring after meals in some POTS patients. Excessive pooling of blood in the abdomen has been shown to occur while the patient is supine and at rest (Tani, Singer, McPhee, Opfer-Gehrking, Haruma, Kajiyama & Low, 2000). The splanchnic vascular bed contains up to 30% of blood volume. Limited autonomic neuropathy causing peripheral denervation may be the cause of increased resting flow and reduced mesenteric resistance in these patients. Sympathetic Overactivity is observed in many POTS patients. The sympathetic overactivity can be secondary to a number of factors, some of which may be peripheral denervation, venous pooling, or end-organ dysfunction (Low et al, 1998). Hyperadrenergic states with elevated norepinephrine levels are often found in patients with sympathetic overactivity. One study found that 29% of POTS patients had elevated norepinephrine levels upon standing, and the mean level was 531 pg/mL (Thieben, Sandroni, Sletten, Benrud-Larson, Fealey, Vernino, Lennon, Shen & Low, 2007). Norepinephrine is similar to adrenaline and is a natural vasoconstrictor. Genetic or acquired deficits in norepinephrine activation may result in hyperadrenergic states that lead to orthostatic intolerance (Shannon, Flattem, Jordan, Jacob, Black, Biaggioni, Blakely & Robertson, 2000). These deficits can cause patients to experience symptoms suggestive of not enough norepinephrine simultaneously with high norepinephrine levels. Many of the mechanisms listed here can result in states of chronic adrenergic activation that lead to orthostatic intolerance. Sympathetic underactivty can also occur in some forms of orthostatic intolerance (Robertson, 2000), such as pure autonomic failure. The above are some of the possible mechanisms that may be resulting in orthostatic intolerance. Physicians should attempt to discover the underlying mechanisms contributing to a patient's symptoms. This will ensure that treatment plans are tailored to target the specific mechanisms resulting in autonomic dysfunction, and that patients will receive the most effective care. References 1. Bou-Holaigah, I., Rowe, P. C., Kan, J., & Calkins, H. (1995). The relationship between neurally mediated hypotension and the chronic fatigue syndrome. Journal of the American Medical Association, 27, 961-967. PMID: 7674527 [PubMed - indexed for MEDLINE] 2. Bush, V. E., Wight, V. L., Brown, C. M., & Hainsworth, R. (2000). Vascular responses to orthostatic stress in patients with postural tachycardia syndrome (POTS), in patients with low orthostatic tolerance, and in asymptomatic controls. Clinical Autonomic Research 10, 279-284. PMID: 11198483 [PubMed - indexed for MEDLINE] 3. Coghlan, H. C. (2002, July). Orthostatic Intolerance. National Dysautonomia Research Foundation Patient Conference. Washington, DC. 4. Fredman, C. S., Biermann, K. M., Patel, V., Uppstrom, E. L., & Auer, A. I. (1995). Transcranial Doppler Ultrasonography during Head-Upright Tilt-Table Testing. Annals of Internal Medicine 123, 848-849. 5. Gordon, V. M., Opfer-Gehrking, T. L., Novak, V., & Low, P. A. (2000). Hemodynamic and symptomatic effects of acute interventions on tilt in patients with postural tachycardia syndrome. Clinical Autonomic Research, 10(1), 29-33. PMID: 10750641 6. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 7. Grubb, B. P., & Karas, B. (1999) Clinical disorders of the autonomic nervous system associated with orthostatic intolerance. Pacing and Clinical Electrophysiology, 22, 798-810. Full text: http://www.ndrf.org/PDF%20Files/disorders.PDF 8. Heitz, U. & Horne, M. M. (2005). Fluid, Electrolyte and Acid-Base Balance. St. Louis, MO: Elsevier Mosby. 9.Hermosillo, A. G., Jauregui-Renaud, K., Kostine, A., Marquez, M. F., Lara, J. L., Cardenas, M. (2002). Comparative study of cerebral blood flow between postural tachycardia and neurocardiogenic syncope, during head-up tilt test. Europace, 4, 369-74. Full text: http://europace.oxfordjournals.org/cgi/reprint/4/4/369 .10. Jacob, G., & Biaggioni I. (1999). Idiopathic orthostatic intolerance and postural tachycardia syndromes. The American Journal of the Medical Sciences, 317, 88-101. PMID: 10037112 11. Jacob, G., Robertson, D., Mosqueda-Garcia, R., Ertl, A. C., Robertson, R. M., Biaggioni, I. (1997). Hypovolemia in syncope and orthostatic intolerance: role of the renin-angiotensin system. American Journal of Medicine, 103(2), 128-133. PMID: 9274896 12. Kuchel, O., Buu, N. T., Hamet, P., Larochelle, P., Gutkowska, J., Schiffrin, E. L., Bourque, M., & Genest, J. (1985). Orthostatic hypotension: a posture-induced hyperdopaminergic state. The American Journal of the Medical Sciences, 289, 3-11. PMID: 3881951 13. Low, P. A. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 14. Low, P. A., Schondorf, R., Novak, V., Sandroni, P., Opfer-Gehrking, T. L., & Novak, P. (1997). Postural Tachycardia Syndrome. In P.A. Low (Ed.), Clinical Autonomic Disorders (pp. 681-697). Philadelphia: Lippincott-Raven Publishers. 15. Novak, V., Novak, P., Opfer-Gehrking, T. L., O'Brien, P. C., & Low P. A. (1998). Clinical and laboratory indices that enhance the diagnosis of postural tachycardia syndrome. Mayo Clinic Proceedings, 73, 1141-50. PMID: 9868411 [PubMed - indexed for MEDLINE] 16. Raj, S. R., Biaggioni, I., Yamhure, P. C., Black, B. K., Paranjape, S. Y., Byrne, D. W., & Robertson, D. (2005). Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Circulation. 111(13), 1574-1582. Full Text 17. Robertson, D. (2000, July). General description of the autonomic nervous system and orthostatic intolerance overview. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 18. Schondorf, R., Benoit, J., & Stein, R. (2005). Cerebral autoregulation is preserved in postural tachycardia syndrome (POTS). Journal of Applied Physiology, Apr 28; [Epub ahead of print] Full Text 19. Shannon, J. R., Flattem, N. L., Jordan, J., Jacob, G., Black, B. K., Biaggioni, I., Blakely, R. D., & Robertson, D. (2000). Orthostatic intolerance and tachycardia associated with norepinephrine-transporter deficiency. New England Journal of Medicine, 24, 541-9. http://content.nejm.org/cgi/content/abstract/342/8/541 20. Stewart, J. M. (2000, July). Pediatric and adolescent orthostatic intolerance and CFIDS. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 21. Stewart, J. M., & Erickson, L.C., (2002). Orthostatic intolerance: an overview. In Alejos, J. C., Konop, R., Chin, A. J., Herzberg, G., Neish, S. (Eds.). emedicine Journal, 3, (1). http://www.emedicine.com/ped/topic2860.htm 22. Stewart, J. M., & Weldon, A. (2001). Reflex vascular defects in the orthostatic tachycardia syndrome of adolescents. Journal of Applied Physiology, 90, 2025-2032. Full text: http://jap.physiology.org/cgi/content/full/90/6/2025 23. Streeten, D. H. (1999). Orthostatic intolerance. A historical introduction to the pathophysiological mechanisms. The American Journal of the Medical Sciences, 317, 78-87. PMID: 10037111 24. Streeten, D. H., & Anderson, G. H. (1992). Delayed orthostatic intolerance. Archives of Internal Medicine, 152, 1066-72 PMID: 1580710 [PubMed - indexed for MEDLINE] 25. Thieben, M. J., Sandroni, P., Sletten, D. N., Benrud-Larson, L. M., Fealey, R. D., Vernino, S., Lennon, V. A., Shen, W. K., & Low, P. A., (2007). Postural orthostatic tachycardia syndrome: the Mayo Clinic experience. Mayo Clin. Proc. 82, (3), 308-313.

Postural Orthostatic Tachycardia is a syndrome. As such, there is a collection of symptoms that distinguish it. The symptoms are widespread because the autonomic nervous system plays an extensive role in regulating functions throughout the body. Many of these symptoms, such as low blood pressure,* may present only after prolonged standing. Symptoms will vary from person to person. The following is a list of symptoms reported by patients. When possible, we have included the percentage of patients that research reports have experienced a given symptom. Symptoms presumed to be related to cerebral hypoperfusion:** Lightheadedness 77.6 % (Grubb, 2000) Fainting or near fainting 60.5% of patients report near fainting (Grubb, 2000) Generalized weakness 50% (Low et al.) Symptoms presumed to be related to autonomic overactivity include the following:** Palpitations 75% (Grubb, 2000) Tremulousness 37.5% (Low, Opffer-Gehrking, Textor, Benarroch, Shen, Schondorf, Suarez & Rummans, 1995) Shortness of breath 27.6 % (Grubb, 2000) Chest discomfort and/or pain 24.3 % (Grubb, 2000) Sudomotor symptoms include the following:** Loss of sweating 5.3 % (Low et al.) Excessive sweating 9.2 % (Robertson, 2000) Loss of sweating and excessive sweating are more common in patients with elevated norepinephrine levels (Thieben, Sandroni, Sletten, Benrud-Larson, Fealey, Vernino, Lennon, Shen & Low, 2007). Symptoms that may reflect dysautonomia:** Delayed gastric emptying 23.7% of patients report gastrointestinal complaints, including bloating (Grubb et al., 1997) Bloating after meals (Grubb et al., 1997) Nausea 38.8% (Robertson, 2000) Vomiting 8.6% (Thieben et al., 2007) Abdominal pain 15.1% (Thieben et al., 2007) Diarrhea 17.8% (Jacob & Biaggioni, 1999) (sometimes with alternating constipation) Constipation 15.1% (Thieben et al., 2007) Bladder dysfunction 9.2% (Thieben et al., 2007) (this may include Polyuria(Jacob & Biaggioni, 1999) (excessive urination) Pupillary dysfunction 3.3% (Thieben et al., 2007) Pupillary dysfunction may or may not be responsible for some other reported symptoms, such as: Blurred Vision (Grubb, 2000) and Tunnel vision (Low et al.). Generalized Complaint symptoms:** Fatigue 48% (Grubb, 2000) (which can be disabling) Sleep disorders 31.6% (Low et al.) (can cause unrefreshing sleep and an increased need for sleep) Headache/migraine 27.6% (Grubb, 2000) Myofascial pain 15.8% (Thieben et al., 2007) (characterized by regional muscle pain accompanied by trigger points) Neuropathic pain 3% (Thieben et al., 2007) Other symptoms reported in research that are not categorized above include: Dizziness (Grubb, 2000) Tachycardia(Grubb, 2000) Exercise intolerance (Grubb, 2000) Clamminess (Grubb, 2000) Anxiety (Grubb, 2000) Flushing (Grubb, 2000) Postprandial hypotension (Grubb, 2000) (low blood pressure after meals) Blood pooling in limbs (Grubb, 2000) (can make legs feel heavy and appear mottled and purple in color) Intolerance to heat (Grubb & Karas, 1999) Feeling cold all over (Grubb & Karas, 1999) Low blood pressure upon standing (Grubb, Kosinski, Boehm & Kip, 1997) (Some physicians feel orthostatic hypotension is a separate entity from POTS) Cognitive impairment (Grubb et al., 1997) (may include difficulties with concentration, brain fog, memory and/or word recall) Narrowing of upright pulse pressure (Jacob & Biaggioni, 1999) Cold hands (Low et al.) (and often feet & nose) Hypovolemia (Low et al.) (low blood volume) Chills (Low et al.) High blood pressure (Low et al.) Hyperventilation (Low et al.) Numbness or tingling sensations (Low et al.) Reduced pulse pressure upon standing (Low et al.) Low back pain (Mathias, 2000) Aching neck and shoulders (Mathias, 2000) Noise sensitivity (Stewart, 2001) Light Sensitivity (Stewart, 2001) Disequalibrium (Sandroni, Opfer-Gehrking, McPhee & Low, 1999) The above are symptoms reported by POTS researchers. Other symptoms sometimes reported by POTS patients include: Arrhythmias (irregular heart beats) Chemical sensitivities (May have multiple chemical sensitivity and can be very sensitive to medications - may only need small doses) Easily over-stimulated Feeling full quickly Feeling "wired" Food allergies/sensitivities (some foods seem to make symptoms worse) Hyperreflexia Irregular menstrual cycles Loss of appetite Loss of sex drive Muscle aches and/or joint pains Swollen nodules/lymph nodes Polydipsia (excessive thirst) Weight loss or gain Feeling detached from surroundings Restless leg syndrome POTS symptoms can vary from day to day. They tend to multiply and become exaggerated upon upright posture. Blood flow and blood pressure regulation are also abnormal while supine or sitting, but these abnormalities may not be as apparent and may require orthostatic stress to become evident (Stewart & Erickson, 2002). Some patients do report symptoms occurring while sitting or lying down. Heat, exercise and eating can exacerbate symptoms. Women sometimes report an increase in symptoms around menstruation. If you are suffering from some of the above symptoms, you need to seek professional help. Please do not attempt self-diagnosis. *Some of the above symptoms are specifically related to orthostatic hypotension, traditionally defined as an excessive fall in BP (typically > 20/10 mm Hg) on assuming the upright posture. Not all patients will experience a drop in blood pressure upon standing. Some physicians define orthostatic hypotension as a separate entity from POTS. ** The hypothesized origin of symptoms and their frequency came from the "Postural Orthostatic Tachycardia Syndrome: The Mayo Clinic Experience" by Thieben, Sandroni, Sletten, Benrud-Larson, Fealey, Vernino, Lennon, Shen & Low, 2007. For more information about POTS, please view the additional articles, resources and links References 1. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 2. Grubb, B. P., & Karas, B. (1999) Clinical disorders of the autonomic nervous system associated with orthostatic intolerance. Pacing and Clinical Electrophysiology, 22, 798-810. Full text: www.ndrf.org/PDF%20Files/disorders.PDF 3. Grubb, B. P., Kosinski, D.J., Boehm, K., & Kip, K. (1997). The postural orthostatic tachycardia syndrome: a neurocardiogenic variant identified during head-up tilttable testing. Pacing and Clinical Electrophysiology, 20, (9, Pt. 1), 2205-12. PMID: 9309745 [PubMed - indexed for MEDLINE] 4. Jacob, G., & Biaggioni I. (1999). Idiopathic orthostatic intolerance and postural tachycardia syndromes. The American Journal of the Medical Sciences, 317, 88-101. PMID: 10037112 [PubMed - indexed for MEDLINE] 5. Low, P. A., Oper-Gehrking, T. L., Textor, S. C., Benarroch, E. E., Shen, W. K., Schondorf, R., Suarez, G. A., & Rummans, T. A. (1995). Postural tachycardia syndrome (POTS). Neurology, 45, (4, Supplement 5), S19-25. PMID: 7746369 [PubMed - indexed for MEDLINE] 6. Mathias, C. J. (2000, July). Other autonomic disorders. National Dysautonomia Research Foundation Patient conference. Minneapolis, Minnesota. 7. Robertson, D. (2000, July). General description of the autonomic nervous system and orthostatic intolerance overview. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 8. Sandroni, P., Opfer-Gehrking, T. L., McPhee, B. R., & Low, P. A. (1999). Postural tachycardia syndrome: clinical features and follow-up study. Mayo Clinic Proceedings, 74, (11), 1106-1110. PMID: 10560597 [PubMed - indexed for MEDLINE] 9. Stewart, J. M., (2001, Spring/Summer). About being young and dizzy: overview of dysautonomia. National Dysautonomia Research Foundation Youth Network Fainting Robins Newsletter, "The Young and the Dizzy", 1, 1-2. 10. Stewart, J. M., & Erickson, L.C., (2002). Orthostatic intolerance: an overview. In Alejos, J. C., Konop, R., Chin, A. J., Herzberg, G., Neish, S. (Eds.). emedicine Journal, 3, (1). http://www.emedicine.com/ped/topic2860.htm 11. Thieben, M. J., Sandroni, P., Sletten, D. N., Benrud-Larson, L. M., Fealey, R. D., Vernino, S., Lennon, V. A., Shen, W. K., & Low, P. A., (2007). Postural orthostatic tachycardia syndrome: the Mayo Clinic experience. Mayo Clin. Proc. 82, (3), 308-313.

Postural Orthostatic Tachycardia is a syndrome. As such, there is a collection of symptoms that distinguish it. The symptoms are widespread because the autonomic nervous system plays an extensive role in regulating functions throughout the body. Many of these symptoms, such as low blood pressure,* may present only after prolonged standing. Symptoms will vary from person to person. The following is a list of symptoms reported by patients. When possible, we have included the percentage of patients that research reports have experienced a given symptom. Symptoms presumed to be related to cerebral hypoperfusion:** Lightheadedness 77.6 % (Grubb, 2000) Fainting or near fainting 60.5% of patients report near fainting (Grubb, 2000) Generalized weakness 50% (Low et al.) Symptoms presumed to be related to autonomic overactivity include the following:** Palpitations 75% (Grubb, 2000) Tremulousness 37.5% (Low, Opffer-Gehrking, Textor, Benarroch, Shen, Schondorf, Suarez & Rummans, 1995) Shortness of breath 27.6 % (Grubb, 2000) Chest discomfort and/or pain 24.3 % (Grubb, 2000) Sudomotor symptoms include the following:** Loss of sweating 5.3 % (Low et al.) Excessive sweating 9.2 % (Robertson, 2000) Loss of sweating and excessive sweating are more common in patients with elevated norepinephrine levels (Thieben, Sandroni, Sletten, Benrud-Larson, Fealey, Vernino, Lennon, Shen & Low, 2007). Symptoms that may reflect dysautonomia:** Delayed gastric emptying 23.7% of patients report gastrointestinal complaints, including bloating (Grubb et al., 1997) Bloating after meals (Grubb et al., 1997) Nausea 38.8% (Robertson, 2000) Vomiting 8.6% (Thieben et al., 2007) Abdominal pain 15.1% (Thieben et al., 2007) Diarrhea 17.8% (Jacob & Biaggioni, 1999) (sometimes with alternating constipation) Constipation 15.1% (Thieben et al., 2007) Bladder dysfunction 9.2% (Thieben et al., 2007) (this may include Polyuria(Jacob & Biaggioni, 1999) (excessive urination) Pupillary dysfunction 3.3% (Thieben et al., 2007) Pupillary dysfunction may or may not be responsible for some other reported symptoms, such as: Blurred Vision (Grubb, 2000) and Tunnel vision (Low et al.). Generalized Complaint symptoms:** Fatigue 48% (Grubb, 2000) (which can be disabling) Sleep disorders 31.6% (Low et al.) (can cause unrefreshing sleep and an increased need for sleep) Headache/migraine 27.6% (Grubb, 2000) Myofascial pain 15.8% (Thieben et al., 2007) (characterized by regional muscle pain accompanied by trigger points) Neuropathic pain 3% (Thieben et al., 2007) Other symptoms reported in research that are not categorized above include: Dizziness (Grubb, 2000) Tachycardia(Grubb, 2000) Exercise intolerance (Grubb, 2000) Clamminess (Grubb, 2000) Anxiety (Grubb, 2000) Flushing (Grubb, 2000) Postprandial hypotension (Grubb, 2000) (low blood pressure after meals) Blood pooling in limbs (Grubb, 2000) (can make legs feel heavy and appear mottled and purple in color) Intolerance to heat (Grubb & Karas, 1999) Feeling cold all over (Grubb & Karas, 1999) Low blood pressure upon standing (Grubb, Kosinski, Boehm & Kip, 1997) (Some physicians feel orthostatic hypotension is a separate entity from POTS) Cognitive impairment (Grubb et al., 1997) (may include difficulties with concentration, brain fog, memory and/or word recall) Narrowing of upright pulse pressure (Jacob & Biaggioni, 1999) Cold hands (Low et al.) (and often feet & nose) Hypovolemia (Low et al.) (low blood volume) Chills (Low et al.) High blood pressure (Low et al.) Hyperventilation (Low et al.) Numbness or tingling sensations (Low et al.) Reduced pulse pressure upon standing (Low et al.) Low back pain (Mathias, 2000) Aching neck and shoulders (Mathias, 2000) Noise sensitivity (Stewart, 2001) Light Sensitivity (Stewart, 2001) Disequalibrium (Sandroni, Opfer-Gehrking, McPhee & Low, 1999) The above are symptoms reported by POTS researchers. Other symptoms sometimes reported by POTS patients include: Arrhythmias (irregular heart beats) Chemical sensitivities (May have multiple chemical sensitivity and can be very sensitive to medications - may only need small doses) Easily over-stimulated Feeling full quickly Feeling "wired" Food allergies/sensitivities (some foods seem to make symptoms worse) Hyperreflexia Irregular menstrual cycles Loss of appetite Loss of sex drive Muscle aches and/or joint pains Swollen nodules/lymph nodes Polydipsia (excessive thirst) Weight loss or gain Feeling detached from surroundings Restless leg syndrome POTS symptoms can vary from day to day. They tend to multiply and become exaggerated upon upright posture. Blood flow and blood pressure regulation are also abnormal while supine or sitting, but these abnormalities may not be as apparent and may require orthostatic stress to become evident (Stewart & Erickson, 2002). Some patients do report symptoms occurring while sitting or lying down. Heat, exercise and eating can exacerbate symptoms. Women sometimes report an increase in symptoms around menstruation. If you are suffering from some of the above symptoms, you need to seek professional help. Please do not attempt self-diagnosis. *Some of the above symptoms are specifically related to orthostatic hypotension, traditionally defined as an excessive fall in BP (typically > 20/10 mm Hg) on assuming the upright posture. Not all patients will experience a drop in blood pressure upon standing. Some physicians define orthostatic hypotension as a separate entity from POTS. ** The hypothesized origin of symptoms and their frequency came from the "Postural Orthostatic Tachycardia Syndrome: The Mayo Clinic Experience" by Thieben, Sandroni, Sletten, Benrud-Larson, Fealey, Vernino, Lennon, Shen & Low, 2007. For more information about POTS, please view the additional articles, resources and links References 1. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 2. Grubb, B. P., & Karas, B. (1999) Clinical disorders of the autonomic nervous system associated with orthostatic intolerance. Pacing and Clinical Electrophysiology, 22, 798-810. Full text: www.ndrf.org/PDF%20Files/disorders.PDF 3. Grubb, B. P., Kosinski, D.J., Boehm, K., & Kip, K. (1997). The postural orthostatic tachycardia syndrome: a neurocardiogenic variant identified during head-up tilttable testing. Pacing and Clinical Electrophysiology, 20, (9, Pt. 1), 2205-12. PMID: 9309745 [PubMed - indexed for MEDLINE] 4. Jacob, G., & Biaggioni I. (1999). Idiopathic orthostatic intolerance and postural tachycardia syndromes. The American Journal of the Medical Sciences, 317, 88-101. PMID: 10037112 [PubMed - indexed for MEDLINE] 5. Low, P. A., Oper-Gehrking, T. L., Textor, S. C., Benarroch, E. E., Shen, W. K., Schondorf, R., Suarez, G. A., & Rummans, T. A. (1995). Postural tachycardia syndrome (POTS). Neurology, 45, (4, Supplement 5), S19-25. PMID: 7746369 [PubMed - indexed for MEDLINE] 6. Mathias, C. J. (2000, July). Other autonomic disorders. National Dysautonomia Research Foundation Patient conference. Minneapolis, Minnesota. 7. Robertson, D. (2000, July). General description of the autonomic nervous system and orthostatic intolerance overview. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 8. Sandroni, P., Opfer-Gehrking, T. L., McPhee, B. R., & Low, P. A. (1999). Postural tachycardia syndrome: clinical features and follow-up study. Mayo Clinic Proceedings, 74, (11), 1106-1110. PMID: 10560597 [PubMed - indexed for MEDLINE] 9. Stewart, J. M., (2001, Spring/Summer). About being young and dizzy: overview of dysautonomia. National Dysautonomia Research Foundation Youth Network Fainting Robins Newsletter, "The Young and the Dizzy", 1, 1-2. 10. Stewart, J. M., & Erickson, L.C., (2002). Orthostatic intolerance: an overview. In Alejos, J. C., Konop, R., Chin, A. J., Herzberg, G., Neish, S. (Eds.). emedicine Journal, 3, (1). http://www.emedicine.com/ped/topic2860.htm 11. Thieben, M. J., Sandroni, P., Sletten, D. N., Benrud-Larson, L. M., Fealey, R. D., Vernino, S., Lennon, V. A., Shen, W. K., & Low, P. A., (2007). Postural orthostatic tachycardia syndrome: the Mayo Clinic experience. Mayo Clin. Proc. 82, (3), 308-313.

An overview of Postural Orthostatic Tachycardia Syndrome Standing up is something most of us take for granted; we've been doing it since childhood. Our bodies automatically adjust to the pull of gravity by increasing vascular tone, heart rate, and cardiac output. Blood vessels contract, heart rates increase and our systolic blood pressure remains the same or decreases slightly while diastolic pressure increases slightly (Brunner & Suddarth, 2000, p. 546). Our bodies operate in perfect homeostasis and we stand up with little effort. However, the simple act of standing up can be a challenge for some people. There are disorders that affect the body's ability to appropriately adjust to the pull of gravity. When the body cannot effectively adjust to upright posture, a person is said to have orthostatic intolerance. Postural orthostatic tachycardia syndrome (POTS) is a disorder characterized by orthostatic intolerance. POTS is a disorder that is a part of the dysautonomia family of disorders. The criteria for diagnosis of POTS is: (1) a sustained increase in HR of at least 30 bpm within 10 minutes of standing (often with an absolute upright HR ≥ 120bpm); (in the absence of sustained orthostatic hypotension (drop in BP > 20/10mm Hg); (2) with symptoms of orthostatic intolerance for at least 6 months. In patients < 19 years of age, there is a higher HR threshold for POTS (increment  ≥40 bpm or absolute uprights HR  ≥ 120 bpm) due to physiological orthostatic tachycardia in adolescents and children (Singer et al., 2012) (Arnold, Ng, Raj, 2018) While the hallmark of POTS is an excessive heart rate increment upon standing, patients often exhibit numerous symptoms of autonomic nervous system dysregulation, and research by the Mayo Clinic suggests POTS is a limited autonomic neuropathy (Thieben, Sandroni, Sletten, Benrud-Larson, Fealey, Vernino, Lennon, Shen & Low, 2007). Many POTS symptoms seem to be caused by an imbalance of the Autonomic Nervous System's (ANS) control over blood flow. It is the autonomic nervous system (ANS) that regulates the needed adjustments in vascular tone, heart rate and blood pressure upon standing. Some of the messages coming from the autonomic nervous system tell the blood vessels to relax or tighten. In people with POTS, the system seems to be out of balance and blood is not going to the right place at the right time to do what the body needs (Fischer, 2007). The autonomic nervous system is responsible for regulating a multitude of organs and functions throughout the body. Some of these functions include temperature, respiration, pupil dilation and constriction, salivation and the digestive tract. A patient experiencing ANS dysregulation may experience abnormalities in the many organs and functions the ANS regulates. For example, around one third to one-half of POTS patients have digestive troubles (Fischer, 2007). The problem is that blood flow is not matching the need, so blood is not going to the right part of the intestinal system when it needs to. As a result, these people have trouble with nausea. For a smaller percentage of patients, the trouble is that there is too much blood in parts of the intestines. The body is attempting to digest food when there is no food to digest. This leads to cramping and colicky-like pains (Fischer, 2007). Patients commonly suffer from cognitive dysfunction, sleep disturbances and exercise intolerance. The symptoms can be exacerbated by numerous factors including dehydration, heat exposure, prolonged recumbency (resting, reclining), alcohol, menstruation, and acute exercise. Syncope (fainting) is not a predominant feature of POTS (only ~20–30% actually pass out, and this is usually thought to be due to vasovagal syncope) (Shen et al., 2017); however, many patients experience frequent pre-syncopal episodes that impair functional capacity. (Arnold, Ng, Raj, 2018) POTS can be categorized as primary, meaning it is idiopathic and not associated with other diseases, or secondary, meaning it is associated with a known disease or disorder (Grubb, Kanjwal & Kosinski, 2006). Common comorbidities include chronic fatigue syndrome, hypermobility type of Ehlers-Danlos syndrome, migraine, bowel irregularities, autoimmune disorders, and fibromyalgia(Garland et al., 2015). POTS is described as a clinical syndrome consisting of multiple heterogeneous disorders (disorders with diverse character). Some have taken to labeling "POTS Subtypes", with article published alluding to hyperadrenergic POTS ("Hyper POTS"), neuropathic POTS ("Neuro POTS"), or hypovolemic POTS. It is important to note that these subtypes do not all have standard definitions therefore there is a non-exclusivity of names with patients often having overlapping clinical features and symptoms that involve more than one subtype. Also, these subtypes do not have universally accepted definitions, so the labels can be misleading. "While one doctor may use the term "Hyper POTS" to refer to a specific set of findings, another doctor might think that it refers to a different set of findings. In theory, this could harm a patient's care. In our experience, these "subtype" labels are not clinically helpful." (Arnold, Ng, Raj 2018) People generally develop POTS after becoming sick with a virus, giving birth, or being exposed to great bodily stressors (i.e. surgery, trauma or chemotherapy). Some people have had POTS their entire lives. Teenagers sometimes develop the disorder during the years of rapid growth, and 75-80% of them can look forward to being asymptomatic when they reach adulthood (Grubb, Kanjwal & Kosinski, 2006). The symptoms of POTS are life-altering and debilitating at times. POTS patients use about three times more energy to stand than a healthy person (Grubb, 2002). It is as if these patients are running in place all the time. Activities such as housework, bathing, and even meals can exacerbate symptoms (Grubb, Kanjwal & Kosinski, 2006). Research shows that POTS patients' quality of life is similar to those with congestive heart failure and chronic obstructive pulmonary disease (Benrud-Larson, Dewar, Sandroni, Rummans, Haythornthwaite & Low, 2002) Twenty-five percent of people with POTS are disabled and unable to work (Goldstein, Robertson, Esler, Straus, & Eisenhofer, 2002). Most patients will have to make some lifestyle adjustments to cope with this disorder. It was once estimated that nearly 500,000 Americans had POTS, which made standing up a challenge (Robertson, 1999). However, with research advances and growing physician education, the number of people found to have POTS symptoms is steadily rising. It is now estimated that one out of every hundred teens has POTS (Fischer, 2007). The minimal requirements to detect POTS on initial evaluation are a detailed medical history, physical examination with orthostatic vitals and a resting 12-lead ECG (Sheldon et al, 2015) The medical history should document medications, other medical conditions including personal and family history of cardiac disease, joint hypermobility, autoimmunity or neurological disorders, and the nature of tachycardia including potential triggers, frequency, time of day, association with pre-syncopal or syncopal episodes, symptoms, and impact on daily activities. (Arnold, Ng, Raj 2018) POTS has a strong female predominance (4–5:1), and primarily affects women of childbearing age. Most patients present with POTS between 13 and 50 years of age, with a family history of orthostatic intolerance reported in approximately 13% of patients (Thieben et al., 2007).The onset can be sudden or gradual. The quantity and severity of symptoms vary from day to day. There are treatments for POTS symptoms which can be tailored to each individual patient, especially if an underlying cause is discovered. Researchers are attempting to identify and treat the mechanisms and causes of POTS. Studies show that most patients will eventually be able to stand up with fewer symptoms (Low, 2000). Most people with POTS can look forward to experiencing improvement with proper treatment. For more information on POTS, please view our other POTS links and resources. References 1. Amy C. Arnold, Jessica Ng, Satish Raj Postural tachycardia syndrome: Diagnosis, Physiology and Prognosis Autonomic Neuroscience, Vol 215 December 2018 https://doi.org/10.1016/j.autneu.2018.02.005 2. Benrud-Larson, L. M., Dewar, M. S., Sandroni, P., Rummans, T. A., Haythornthwaite, J. A., & Low, P. A. (2002, June). Quality of life in patients with postural tachycardia syndrome. Mayo Clinic Proceedings, 77, 531-537. Full text: http://www.mayoclinicproceedings.com/inside.asp? AID=112&UID= 3. Brunner, L. S. & Suddarth, D. S. (2000). Assessment of cardiovascular function. In S. C. Smeltzer & B. G. Bare (Eds.), Brunner and Suddarth's textbook medical-surgical nursing (pp. 532-563). Philadelphia, PA: Lippincott Williams and Wilkins. 4. Fischer, P. (2007). Postural orthostatic tachycardia syndrome. Mayo Clinic Podcast. http://www.podcastingnews.com/details/www. mayoclinic.org/rss/heart-podcast.xml/view.htm 5. Goldstein, D., Robertson, D., Esler, M., Straus, S., & Eisenhofer, G. (2002). Dysautonomias: clinical disorders of the autonomic nervous System. Ann Intern Med., 137, 753–763. Full Text 6. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 7. Grubb, B. P. (2002, October). The heterogeneity of symptoms related to dysautonomia. Symposium conducted at the meeting of the National Dysautonomia Research Foundation Northwest Ohio Support Group. Toledo, Ohio. 8. Grubb B. P., Kanjwal, Y., & Kosinski, D. J. (2006). The postural tachycardia syndrome: A concise guide to diagnosis and management. J Cardiovasc Electrophysiol., 17, 108-112. 9. Grubb, B. P., & McMann, M. C. (2001). The Fainting Phenomenon: Understanding why people faint and what can be done about it. New York: Futura Publishing Company. 10. Low, P. A. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 11. Robertson, D. (1999). The epidemic of orthostatic tachycardia and orthostatic intolerance. The American Journal of the Medical Sciences, 317, 75- 77. 12. Thieben, M. J., Sandroni, P., Sletten, D. N., Benrud-Larson, L. M., Fealey, R. D., Vernino, S., Lennon, V. A., Shen, W. K., & Low, P. A., (2007). Postural orthostatic tachycardia syndrome: the Mayo Clinic experience. Mayo Clin. Proc. 82, (3), 308-313. Full Text

An overview of Postural Orthostatic Tachycardia Syndrome Standing up is something most of us take for granted; we've been doing it since childhood. Our bodies automatically adjust to the pull of gravity by increasing vascular tone, heart rate, and cardiac output. Blood vessels contract, heart rates increase and our systolic blood pressure remains the same or decreases slightly while diastolic pressure increases slightly (Brunner & Suddarth, 2000, p. 546). Our bodies operate in perfect homeostasis and we stand up with little effort. However, the simple act of standing up can be a challenge for some people. There are disorders that affect the body's ability to appropriately adjust to the pull of gravity. When the body cannot effectively adjust to upright posture, a person is said to have orthostatic intolerance. Postural orthostatic tachycardia syndrome (POTS) is a disorder characterized by orthostatic intolerance. POTS is a disorder that is a part of the dysautonomia family of disorders. The criteria for diagnosis of POTS is: (1) a sustained increase in HR of at least 30 bpm within 10 minutes of standing (often with an absolute upright HR ≥ 120bpm); (2) in the absence of sustained orthostatic hypotension (drop in BP > 20/10mm Hg); (3) with symptoms of orthostatic intolerance for at least 6 months. In patients < 19 years of age, there is a higher HR threshold for POTS (increment  ≥40 bpm or absolute uprights HR  ≥ 120 bpm) due to physiological orthostatic tachycardia in adolescents and children (Singer et al., 2012) (Arnold, Ng, Raj, 2018) While the hallmark of POTS is an excessive heart rate increment upon standing, patients often exhibit numerous symptoms of autonomic nervous system dysregulation, and research by the Mayo Clinic suggests POTS is a limited autonomic neuropathy (Thieben, Sandroni, Sletten, Benrud-Larson, Fealey, Vernino, Lennon, Shen & Low, 2007). Many POTS symptoms seem to be caused by an imbalance of the Autonomic Nervous System's (ANS) control over blood flow. It is the autonomic nervous system (ANS) that regulates the needed adjustments in vascular tone, heart rate and blood pressure upon standing. Some of the messages coming from the autonomic nervous system tell the blood vessels to relax or tighten. In people with POTS, the system seems to be out of balance and blood is not going to the right place at the right time to do what the body needs (Fischer, 2007). The autonomic nervous system is responsible for regulating a multitude of organs and functions throughout the body. Some of these functions include temperature, respiration, pupil dilation and constriction, salivation and the digestive tract. A patient experiencing ANS dysregulation may experience abnormalities in the many organs and functions the ANS regulates. For example, around one third to one-half of POTS patients have digestive troubles (Fischer, 2007). The problem is that blood flow is not matching the need, so blood is not going to the right part of the intestinal system when it needs to. As a result, these people have trouble with nausea. For a smaller percentage of patients, the trouble is that there is too much blood in parts of the intestines. The body is attempting to digest food when there is no food to digest. This leads to cramping and colicky-like pains (Fischer, 2007). Patients commonly suffer from cognitive dysfunction, sleep disturbances and exercise intolerance. The symptoms can be exacerbated by numerous factors including dehydration, heat exposure, prolonged recumbency (resting, reclining), alcohol, menstruation, and acute exercise. Syncope (fainting) is not a predominant feature of POTS (only ~20–30% actually pass out, and this is usually thought to be due to vasovagal syncope) (Shen et al., 2017); however, many patients experience frequent pre-syncopal episodes that impair functional capacity. (Arnold, Ng, Raj, 2018) POTS can be categorized as primary, meaning it is idiopathic and not associated with other diseases, or secondary, meaning it is associated with a known disease or disorder (Grubb, Kanjwal & Kosinski, 2006). Common comorbidities include chronic fatigue syndrome, hypermobility type of Ehlers-Danlos syndrome, migraine, bowel irregularities, autoimmune disorders, and fibromyalgia(Garland et al., 2015). POTS is described as a clinical syndrome consisting of multiple heterogeneous disorders (disorders with diverse character). Some have taken to labeling "POTS Subtypes", with article published alluding to hyperadrenergic POTS ("Hyper POTS"), neuropathic POTS ("Neuro POTS"), or hypovolemic POTS. It is important to note that these subtypes do not all have standard definitions therefore there is a non-exclusivity of names with patients often having overlapping clinical features and symptoms that involve more than one subtype. Also, these subtypes do not have universally accepted definitions, so the labels can be misleading. "While one doctor may use the term "Hyper POTS" to refer to a specific set of findings, another doctor might think that it refers to a different set of findings. In theory, this could harm a patient's care. In our experience, these "subtype" labels are not clinically helpful." (Arnold, Ng, Raj 2018) People generally develop POTS after becoming sick with a virus, giving birth, or being exposed to great bodily stressors (i.e. surgery, trauma or chemotherapy). Some people have had POTS their entire lives. Teenagers sometimes develop the disorder during the years of rapid growth, and 75-80% of them can look forward to being asymptomatic when they reach adulthood (Grubb, Kanjwal & Kosinski, 2006). The symptoms of POTS are life-altering and debilitating at times. POTS patients use about three times more energy to stand than a healthy person (Grubb, 2002). It is as if these patients are running in place all the time. Activities such as housework, bathing, and even meals can exacerbate symptoms (Grubb, Kanjwal & Kosinski, 2006). Research shows that POTS patients' quality of life is similar to those with congestive heart failure and chronic obstructive pulmonary disease (Benrud-Larson, Dewar, Sandroni, Rummans, Haythornthwaite & Low, 2002) Twenty-five percent of people with POTS are disabled and unable to work (Goldstein, Robertson, Esler, Straus, & Eisenhofer, 2002). Most patients will have to make some lifestyle adjustments to cope with this disorder. It was once estimated that nearly 500,000 Americans had POTS, which made standing up a challenge (Robertson, 1999). However, with research advances and growing physician education, the number of people found to have POTS symptoms is steadily rising. It is now estimated that one out of every hundred teens has POTS (Fischer, 2007). The minimal requirements to detect POTS on initial evaluation are a detailed medical history, physical examination with orthostatic vitals and a resting 12-lead ECG (Sheldon et al, 2015) The medical history should document medications, other medical conditions including personal and family history of cardiac disease, joint hypermobility, autoimmunity or neurological disorders, and the nature of tachycardia including potential triggers, frequency, time of day, association with pre-syncopal or syncopal episodes, symptoms, and impact on daily activities. (Arnold, Ng, Raj 2018) POTS has a strong female predominance (4–5:1), and primarily affects women of childbearing age. Most patients present with POTS between 13 and 50 years of age, with a family history of orthostatic intolerance reported in approximately 13% of patients (Thieben et al., 2007).The onset can be sudden or gradual. The quantity and severity of symptoms vary from day to day. There are treatments for POTS symptoms which can be tailored to each individual patient, especially if an underlying cause is discovered. Researchers are attempting to identify and treat the mechanisms and causes of POTS. Studies show that most patients will eventually be able to stand up with fewer symptoms (Low, 2000). Most people with POTS can look forward to experiencing improvement with proper treatment. For more information on POTS, please view our other POTS links and resources. References 1. Amy C. Arnold, Jessica Ng, Satish Raj Postural tachycardia syndrome: Diagnosis, Physiology and Prognosis Autonomic Neuroscience, Vol 215 December 2018 https://doi.org/10.1016/j.autneu.2018.02.005 2. Benrud-Larson, L. M., Dewar, M. S., Sandroni, P., Rummans, T. A., Haythornthwaite, J. A., & Low, P. A. (2002, June). Quality of life in patients with postural tachycardia syndrome. Mayo Clinic Proceedings, 77, 531-537. Full text: http://www.mayoclinicproceedings.com/inside.asp? AID=112&UID= 3. Brunner, L. S. & Suddarth, D. S. (2000). Assessment of cardiovascular function. In S. C. Smeltzer & B. G. Bare (Eds.), Brunner and Suddarth's textbook medical-surgical nursing (pp. 532-563). Philadelphia, PA: Lippincott Williams and Wilkins. 4. Fischer, P. (2007). Postural orthostatic tachycardia syndrome. Mayo Clinic Podcast. http://www.podcastingnews.com/details/www. mayoclinic.org/rss/heart-podcast.xml/view.htm 5. Goldstein, D., Robertson, D., Esler, M., Straus, S., & Eisenhofer, G. (2002). Dysautonomias: clinical disorders of the autonomic nervous System. Ann Intern Med., 137, 753–763. Full Text 6. Grubb, B. P. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 7. Grubb, B. P. (2002, October). The heterogeneity of symptoms related to dysautonomia. Symposium conducted at the meeting of the National Dysautonomia Research Foundation Northwest Ohio Support Group. Toledo, Ohio. 8. Grubb B. P., Kanjwal, Y., & Kosinski, D. J. (2006). The postural tachycardia syndrome: A concise guide to diagnosis and management. J Cardiovasc Electrophysiol., 17, 108-112. 9. Grubb, B. P., & McMann, M. C. (2001). The Fainting Phenomenon: Understanding why people faint and what can be done about it. New York: Futura Publishing Company. 10. Low, P. A. (2000, July). Orthostatic intolerance. National Dysautonomia Research Foundation Patient Conference. Minneapolis, Minnesota. 11. Robertson, D. (1999). The epidemic of orthostatic tachycardia and orthostatic intolerance. The American Journal of the Medical Sciences, 317, 75- 77. 12. Thieben, M. J., Sandroni, P., Sletten, D. N., Benrud-Larson, L. M., Fealey, R. D., Vernino, S., Lennon, V. A., Shen, W. K., & Low, P. A., (2007). Postural orthostatic tachycardia syndrome: the Mayo Clinic experience. Mayo Clin. Proc. 82, (3), 308-313. Full Text

Please keep in mind that recent clinical findings will not be included in earlier publications. General Information Multiple System Atrophy, Dr. Andre Diedrich: http://emedicine.medscape.com/article/1154583-overview Multiple System Atrophy: Medline Plus.gov: https://medlineplus.gov/ency/article/000757.htm Multiple System Atrophy by Laurie Swan and Jerome Dupont: http://www.ptjournal.org/cgi/reprint/79/5/488 Primary Autonomic Failure: Three Clinical Presentations of One Disease? by Horacio Kaufmann: http://www.mssm.edu/neurology/autodis/disorders/parkinson/Primary.pdf Clinical Characteristics of Patients with Multiple System Atrophy in Singapore by RDG Jamora, A Gupta, AKY Tan & LCS Tan: http://www.annals.edu.sg/pdf/34VolNo9200510/V34N9p553.pdf Hypotension and/or hypertension The recommendations of a consensus panel for the screening, diagnosis, and treatment of neurogenic orthostatic hypotension and associated supine hypertension, by Gibbons, C.H., Schmidt, P., Biaggioni, I. et al. J Neurol (2017) https://link.springer.com/article/10.1007/s00415-016-8375-x/fulltext.html Sympathetically Mediated Hypertension in Autonomic Failure by John R. Shannon, Jens Jordan, Andre Diedrich, Bojan Pohar, Bonnie K. Black, David Robertson and Italo Biaggioni: http://circ.ahajournals.org/cgi/content/full/101/23/2710 Impairment Neuropsychological functions in progressive supranuclear palsy, multiple system atrophy and Parkinson's disease: http://www.neurologyindia.com/article.asp?issn=0028-3886;year=2006;volume=54;issue=3;spage=268;epage=272;aulast=Krishnan Raynaud's Phenomenon Raynaud's Phenomenon after Sympathetic Denervation in Patients with Primary Autonomic Failure: Questionnaire Survey by Rajeev Mallipeddi and Christopher J Mathias: http://bmj.com/cgi/content/full/316/7129/438 Tests/Detection REM Sleep Behaviour Disorder Differentiates Pure Autonomic Failure from Multiple System Atrophy with Autonomic Failure by Giuseppe Plazzi, Pietro Cortelli, Pasquale Montagna, Alessandro De Monte, Raffaella Corsini, Manuela Contin, Federica Provini, Giulia Pierangeli, Elio Lugaresi: http://jnnp.bmjjournals.com/cgi/content/full/64/5/683 Multiple System Atrophy Presenting as Central Sleep Apnoea by L.J. Cormican, S. Higgins, A.C. Davidson, R. Howard and A.J. Williams: http://erj.ersjournals.com/cgi/reprint/24/2/323.pdf#search =%22multiple%20system%20atrophy%20filetype%3Apdf%22 Treatment Diagnosis and Treatment of Multiple System Atrophy: An Update by Gregor Wenning and Felix Geser: http://www.acnr.co.uk/pdfs/volume3issue6/v3i6reviewart1.pdf# search=%22multiple%20system%20atrophy%20filetype%3Apdf%22 The Pressor Response to Water Drinking in Humans by Jens Jordan, John R. Shannon, Bonnie K. Black, Yasmine Ali, Mary Farley; Fernando Costa, Andre Diedrich, Rose Marie Robertson, Italo Biaggioni and David Robertson: http://circ.ahajournals.org/cgi/content/full/101/5/504 The Hypertension of Autonomic Failure and its Treatment by John Shannon, Jens Jordan, Fernando Costa, Rose Marie Robertson, and Italo Biaggioni: http://hyper.ahajournals.org/cgi/content/full/30/5/1062 The natural history of multiple system atrophy: a prospective European cohort study, Dr. Christopher Mathias et al: http://www.thelancet.com/journals/laneur/article/PIIS1474-4422(12)70327-7/fulltext Support Groups The Multiple System Atrophy Coalition 8311 Brier Creek Parkway Suite 105-434 Raleigh, NC 27617 Tel: 1-866-737-5999 www.multiple-system-atrophy.org contacts: Judy Biedenharn jbiedenharn@msacoalition.org Vera James vjames@msacoalition.org Pam Bower pbower@msacoalition.org Carol Langer clanger@msacoalition.org Don Crouse dcrouse@msacoalition.org

Please keep in mind that recent clinical findings will not be included in earlier publications. General Information Multiple System Atrophy, Dr. Andre Diedrich: http://emedicine.medscape.com/article/1154583-overview Multiple System Atrophy: Medline Plus.gov: https://medlineplus.gov/ency/article/000757.htm Multiple System Atrophy by Laurie Swan and Jerome Dupont: http://www.ptjournal.org/cgi/reprint/79/5/488 Primary Autonomic Failure: Three Clinical Presentations of One Disease? by Horacio Kaufmann: http://www.mssm.edu/neurology/autodis/disorders/parkinson/Primary.pdf Clinical Characteristics of Patients with Multiple System Atrophy in Singapore by RDG Jamora, A Gupta, AKY Tan & LCS Tan: http://www.annals.edu.sg/pdf/34VolNo9200510/V34N9p553.pdf Hypotension and/or hypertension The recommendations of a consensus panel for the screening, diagnosis, and treatment of neurogenic orthostatic hypotension and associated supine hypertension, by Gibbons, C.H., Schmidt, P., Biaggioni, I. et al. J Neurol (2017) https://link.springer.com/article/10.1007/s00415-016-8375-x/fulltext.html Sympathetically Mediated Hypertension in Autonomic Failure by John R. Shannon, Jens Jordan, Andre Diedrich, Bojan Pohar, Bonnie K. Black, David Robertson and Italo Biaggioni: http://circ.ahajournals.org/cgi/content/full/101/23/2710 Impairment Neuropsychological functions in progressive supranuclear palsy, multiple system atrophy and Parkinson's disease: http://www.neurologyindia.com/article.asp?issn=0028-3886;year=2006;volume=54;issue=3;spage=268;epage=272;aulast=Krishnan Raynaud's Phenomenon Raynaud's Phenomenon after Sympathetic Denervation in Patients with Primary Autonomic Failure: Questionnaire Survey by Rajeev Mallipeddi and Christopher J Mathias: http://bmj.com/cgi/content/full/316/7129/438 Tests/Detection REM Sleep Behaviour Disorder Differentiates Pure Autonomic Failure from Multiple System Atrophy with Autonomic Failure by Giuseppe Plazzi, Pietro Cortelli, Pasquale Montagna, Alessandro De Monte, Raffaella Corsini, Manuela Contin, Federica Provini, Giulia Pierangeli, Elio Lugaresi: http://jnnp.bmjjournals.com/cgi/content/full/64/5/683 Multiple System Atrophy Presenting as Central Sleep Apnoea by L.J. Cormican, S. Higgins, A.C. Davidson, R. Howard and A.J. Williams: http://erj.ersjournals.com/cgi/reprint/24/2/323.pdf#search =%22multiple%20system%20atrophy%20filetype%3Apdf%22 Treatment Diagnosis and Treatment of Multiple System Atrophy: An Update by Gregor Wenning and Felix Geser: http://www.acnr.co.uk/pdfs/volume3issue6/v3i6reviewart1.pdf# search=%22multiple%20system%20atrophy%20filetype%3Apdf%22 The Pressor Response to Water Drinking in Humans by Jens Jordan, John R. Shannon, Bonnie K. Black, Yasmine Ali, Mary Farley; Fernando Costa, Andre Diedrich, Rose Marie Robertson, Italo Biaggioni and David Robertson: http://circ.ahajournals.org/cgi/content/full/101/5/504 The Hypertension of Autonomic Failure and its Treatment by John Shannon, Jens Jordan, Fernando Costa, Rose Marie Robertson, and Italo Biaggioni: http://hyper.ahajournals.org/cgi/content/full/30/5/1062 The natural history of multiple system atrophy: a prospective European cohort study, Dr. Christopher Mathias et al: http://www.thelancet.com/journals/laneur/article/PIIS1474-4422(12)70327-7/fulltext Support Groups The Multiple System Atrophy Coalition 8311 Brier Creek Parkway Suite 105-434 Raleigh, NC 27617 Tel: 1-866-737-5999 www.multiple-system-atrophy.org contacts: Judy Biedenharn jbiedenharn@msacoalition.org Vera James vjames@msacoalition.org Pam Bower pbower@msacoalition.org Carol Langer clanger@msacoalition.org Don Crouse dcrouse@msacoalition.org

Please keep in mind that recent clinical findings will not be included in earlier publications. General Information Alternative Names: \Shy-Drager syndrome; Neurologic orthostatic hypotension; Shy-McGee-Drager syndrome; Parkinson plus syndrome; MSA-P; MSA-C Vanderbilt University Autonomic Dysfunction Center: http://www.mc.vanderbilt.edu/root/vumc.php?site=adc&doc=4790 A Review of the Classification, Diagnosis, and Management of Autonomic Dysfunction Syndromes Associated with Orthostatic Intolerance by Blair P. Grubb and Sergio do Carmo Jorge: http://publicacoes.cardiol.br/abc/2000/7406/74060008i.pdf The Natural History of Pure Autonomic Failure: a U.S. Prospective Cohort, Dr. Kaufman, Dr. Low et al: https://www.ncbi.nlm.nih.gov/pubmed/28093795 Identification of a Renin Threshold and Its Relationship to Salt Intake in a Patient With Pure Autonomic Failure by Henriette Hohenbleicher; Fabian Klosterman; Ulrike Schorr; Sepp Seyfert; Pontus B. Persson and Arya M. Sharma: http://hyper.ahajournals.org/cgi/content/full/30/5/1068 Orthostatic Tolerance, Cerebral Oxygenation, and Blood Velocity in Humans With Sympathetic Failure by Harms M. P., Colier W. N., Wieling W., Lenders J. W., Secher N. H., van Lieshout J. J.: http://stroke.ahajournals.org/cgi/content/full/31/7/1608 Causes/Mechanisms The Distribution of Lewy Bodies in Pure Autonomic Failure: Autopsy Findings and Review of the Literature by K. Hague, P. Lento, S. Morgello, S. Laro and H. Kaufmann: http://www.springerlink.com/content/cm7nrxyrh9lru35j/fulltext.pdf?page=1 Hypotension and/or Hypertension Stress induced hypotension in pure autonomic failure by R D Thijs and J G van Dijk: http://jnnp.bmjjournals.com/cgi/content/abstract/77/4/552 Orthostatic Hypotension by Bradley JG, Davis KA. http://www.aafp.org/afp/20031215/2393.pdf Autoregulation of Cerebral Blood Flow in Orthostatic Hypotension by Novak V., Novak P., Spies J. M., Low P. A.: http://stroke.ahajournals.org/cgi/content/full/29/1/104 Neck and other muscle pains in autonomic failure: their association with orthostatic hypotension by K M Bleasdale-Barr and C J Mathias: http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1296807&blobtype=pdf Cognitive functioning in orthostatic hypotension due to pure autonomic failure by Heims HC, Critchley HD, Martin NH, Jager HR, Mathias, CJ, Cipolotti L.: http://www.ncbi.nlm.nih.gov/pubmed/16683070 The Hypertension of Autonomic Failure and it's Treatment, Dr. Bioganni, Dr. Rose Marie Roberson et all: http://hyper.ahajournals.org/content/30/5/1062.full Sympathetically Mediated Hypertension in Autonomic Failure by John R. Shannon, Jens Jordan, Andre Diedrich, Bojan Pohar, Bonnie K. Black, David Robertson, Italo Biaggioni: http://circ.ahajournals.org/cgi/content/abstract/101/23/2710?ck=nck Vasopressin and Blood Pressure in Humans by Jens Jordan and Jens Tank: http://hyper.ahajournals.org/cgi/content/full/36/6/e3 Outlook Progression and prognosis in pure autonomic failure (PAF): comparison with multiple system atrophy by N Mabuchi, M Hirayama, Y Koike, H Watanabe, H Ito, R Kobayashi, K Hamada and G Sobue: http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1739727&blobtype=pdf Sleep A Sound Night's Rest may do no good in Autonomic Failure! by Christopher J. Mathias: http://cs.portlandpress.co.uk/cs/101/0619/1010619.pdf Tests Hormonal and cardiovascular reflex assessment in a female patient with pure autonomic failure by Lopes HF, Consolim-Colombo FM, Hachul D, Carvalho ME, Pileggi F, Silva HB: http://www.scielo.br/pdf/abc/v75n3/2870.pdf Treatments The Pressor Response to Water Drinking in Humans by Jens Jordan, John R. Shannon, Bonnie K. Black, Yasmine Ali, Mary Farley; Fernando Costa, Andre Diedrich, Rose Marie Robertson, Italo Biaggioni and David Robertson: http://circ.ahajournals.org/cgi/content/full/101/5/504

Please keep in mind that recent clinical findings will not be included in earlier publications. General Information Alternative Names: \Shy-Drager syndrome; Neurologic orthostatic hypotension; Shy-McGee-Drager syndrome; Parkinson plus syndrome; MSA-P; MSA-C Vanderbilt University Autonomic Dysfunction Center: http://www.mc.vanderbilt.edu/root/vumc.php?site=adc&doc=4790 A Review of the Classification, Diagnosis, and Management of Autonomic Dysfunction Syndromes Associated with Orthostatic Intolerance by Blair P. Grubb and Sergio do Carmo Jorge: http://publicacoes.cardiol.br/abc/2000/7406/74060008i.pdf The Natural History of Pure Autonomic Failure: a U.S. Prospective Cohort, Dr. Kaufman, Dr. Low et al: https://www.ncbi.nlm.nih.gov/pubmed/28093795 Identification of a Renin Threshold and Its Relationship to Salt Intake in a Patient With Pure Autonomic Failure by Henriette Hohenbleicher; Fabian Klosterman; Ulrike Schorr; Sepp Seyfert; Pontus B. Persson and Arya M. Sharma: http://hyper.ahajournals.org/cgi/content/full/30/5/1068 Orthostatic Tolerance, Cerebral Oxygenation, and Blood Velocity in Humans With Sympathetic Failure by Harms M. P., Colier W. N., Wieling W., Lenders J. W., Secher N. H., van Lieshout J. J.: http://stroke.ahajournals.org/cgi/content/full/31/7/1608 Causes/Mechanisms The Distribution of Lewy Bodies in Pure Autonomic Failure: Autopsy Findings and Review of the Literature by K. Hague, P. Lento, S. Morgello, S. Laro and H. Kaufmann: http://www.springerlink.com/content/cm7nrxyrh9lru35j/fulltext.pdf?page=1 Hypotension and/or Hypertension Stress induced hypotension in pure autonomic failure by R D Thijs and J G van Dijk: http://jnnp.bmjjournals.com/cgi/content/abstract/77/4/552 Orthostatic Hypotension by Bradley JG, Davis KA. http://www.aafp.org/afp/20031215/2393.pdf Autoregulation of Cerebral Blood Flow in Orthostatic Hypotension by Novak V., Novak P., Spies J. M., Low P. A.: http://stroke.ahajournals.org/cgi/content/full/29/1/104 Neck and other muscle pains in autonomic failure: their association with orthostatic hypotension by K M Bleasdale-Barr and C J Mathias: http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1296807&blobtype=pdf Cognitive functioning in orthostatic hypotension due to pure autonomic failure by Heims HC, Critchley HD, Martin NH, Jager HR, Mathias, CJ, Cipolotti L.: http://www.ncbi.nlm.nih.gov/pubmed/16683070 The Hypertension of Autonomic Failure and it's Treatment, Dr. Bioganni, Dr. Rose Marie Roberson et all: http://hyper.ahajournals.org/content/30/5/1062.full Sympathetically Mediated Hypertension in Autonomic Failure by John R. Shannon, Jens Jordan, Andre Diedrich, Bojan Pohar, Bonnie K. Black, David Robertson, Italo Biaggioni: http://circ.ahajournals.org/cgi/content/abstract/101/23/2710?ck=nck Vasopressin and Blood Pressure in Humans by Jens Jordan and Jens Tank: http://hyper.ahajournals.org/cgi/content/full/36/6/e3 Outlook Progression and prognosis in pure autonomic failure (PAF): comparison with multiple system atrophy by N Mabuchi, M Hirayama, Y Koike, H Watanabe, H Ito, R Kobayashi, K Hamada and G Sobue: http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1739727&blobtype=pdf Sleep A Sound Night's Rest may do no good in Autonomic Failure! by Christopher J. Mathias: http://cs.portlandpress.co.uk/cs/101/0619/1010619.pdf Tests Hormonal and cardiovascular reflex assessment in a female patient with pure autonomic failure by Lopes HF, Consolim-Colombo FM, Hachul D, Carvalho ME, Pileggi F, Silva HB: http://www.scielo.br/pdf/abc/v75n3/2870.pdf Treatments The Pressor Response to Water Drinking in Humans by Jens Jordan, John R. Shannon, Bonnie K. Black, Yasmine Ali, Mary Farley; Fernando Costa, Andre Diedrich, Rose Marie Robertson, Italo Biaggioni and David Robertson: http://circ.ahajournals.org/cgi/content/full/101/5/504