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Excessive Heart Rate Response To Orthostatic Stress In Postural Tachycardia Syndrome

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Thought this article might be helpful to those of you who have been misdiagnosed with anxiety disorder:

J Appl Physiol. 2006 Nov 16;

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.

Sports Medical Sciences, Shinshu University Graduate School of Medicine, Shinshu, Minnesota, Japan; Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States.

Postural tachycardia syndrome (POTS) is characterized by excessive increases in heart rate (HR) without hypotension during orthostasis. The relationship between the tachycardia and anxiety is uncertain. Therefore, we tested whether the HR response to orthostatic stress in POTS is primarily related to psychological factors. POTS patients (n=14) and healthy controls (n=10) underwent graded venous pooling with lower body negative pressure (LBNP) to -40 mmHg while wearing deflated antishock trousers. "Sham" venous pooling was performed by: 1) trouser inflation to 5 mmHg during LBNP and 2) vacuum pump activation without LBNP. HR responses to mental stress were also measured in both groups, and a questionnaire was used to measure psychological parameters. During LBNP, HR in POTS patients increased 39+/-5 beats/min vs. 19+/-3 beats/min in control subjects at -40 mmHg (P<0.01). LBNP with trouser inflation markedly blunted the HR responses in the patients (9+/-2 beats/min) and controls (2+/-1 beats/min), and there was no HR increase during vacuum application without LBNP in either group. HR responses during mental stress were not different in the patients and controls (18+/-2 vs 19+/-1 beats/min; P>0.6). Anxiety, somatic vigilance, and catastrophic cognitions were significantly higher in the patients (P<0.05), but not related to the HR responses during LBNP or mental stress (P>0.1). These results suggest that the HR response to orthostatic stress in POTS patients is not caused by anxiety, but is a physiological response that maintains arterial pressure during venous pooling.

Key words: Orthostatic intolerance, Venous pooling, Blood pressure, Sympathetic nervous system, Mental stress.

PMID: 17110507


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"HR responses during mental stress were not different in the patients and controls (18+/-2 vs 19+/-1 beats/min; P>0.6). Anxiety, somatic vigilance, and catastrophic cognitions were significantly higher in the patients (P<0.05), but not related to the HR responses during LBNP or mental stress (" ....what exactly does that mean?

good article but what exactly was the "mental stress" that they performed or tried to instigate on both patients and subjects? also, does anyone know, since this article is talking about LBNP and pooling factors, what percentage differences of pooling occur btwn patients and controls? it would be more logical in these studies to not get so stuck on HR's as proof of whether or not there is an anxiety issue with patients vs. controls (as anyone can conclude anxiety, or somatic anxiety with an increase in HR) but someone should focus more on this pooling issue or some other physiologic factor that is occuring in patients that does not occur in controls (cuz even controls have increased HR's with LBNP, even if only at a smaller tachy response than with patients) ..........

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Cardiactec, as for what mental stressors are used, you should look at the references from the article; they should cite which mental "stress" tasks were performed.

My training is in the behavioral sciences--my first degree is in psychology and laboratory science. My current program is interdepartmental--covering the departments of 1)psychology, 2) educational psychology and 3) special education. There are many "standard" tasks they might use for all subjects during the mental stress condition, such as having them perform difficult memory, math or language activities, along with urging from assistants and/or researchers to "go faster!", do better, work harder, etc. They are typically done the same way for each subject so that you're comparing responses in an "apples to apples" manner (i.e. standardized). This would then allow reseachers to see what dfferences, if any, happen in heart rate, blood pressure, respiratory rate, etc.


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hey nina,

very interesting. i was in a POTS based research about 6 months ago and they performed a "mental stress test" while i was supine. they did exactly what you just mentioned. asking to go "faster" with trying to solve math equations, words, etc and i was pretty stressed. lol. which was the purpose of the test. surprised, well not completely, to see my rates at 147 WHILE STILL SUPINE (as math has always been a big stressor for me, as well as performing - like oral presentations ,etc). i thought that the mental stress test was the worst part of testing overall for me (even over the tilt, the cold water pressor test, hand grip, etc) .........

so from a psychological point of view, you would think they would just some it up as anxiety in my case if my HR's supine were 147 but my heart rates standing are much higher than 147 (more like 210),

---- my point is, heart rate response to mental stress and physical stress be similar depending on etiology. the body doesnt necessarily, depending on etiology, differntiate btwn good stress and bad stress, physical stress and mental stress. if there was an abnormality lets say in catecholamine production or re-uptake, the body would respond the same HR wise to mental or physical stressor (ex. trying to solve math equations as fast as you can vs. standing up for 10 minutes)

if the underlying etiology has nothing to do with a peripheral neuropathy/connective tissue factor/metabolic/post viral issue etc of some sort as being the cause to an excessive HR when someone stands, but say a catecholamine issue, the HR would respond the same as it would to both mental AND physical stress. if an underlying etiology in specific people is a problem with catecholamine release or adrenal reuptake or not enough acetylcholine than the HR response would be similar, whether triggered mentally or physically (because both require release of cathechol's/adrenal/sympathetic activation). i guess this could be part of the hyperadregernic form of pots, not necessarily neurpathy or post viral form of pots. do you know what i mean?

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I think I might take a copy of that article to the first doctor I saw when being tested with my heartrate... She wouldn't listen to a word I said and insisted it was anxioty... THANKS SO MUCH FOR THE ARTICLE!

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Guest tearose

Thanks for the information...

It has been a long time since I read some new information.

I'll read it again since it is not sinking in to my head tonight...

...mental stress I guess...and what da ya know, no elevation in heart rate! :)

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thanks for that article, it was really interesting.

before i was diagnosed wih pots i was "diagnosed" by my gp with psycogenic syncope! sent to see to shrinks before that one was thrown out! an they told me that because i had suffered from depression i was having anxiety attacks - but because of having depression and anxiety attacks before i got pots i knew that wasn't what was hapening. i'm gld i fought on.

interesting article to show to my new gp's though - they have automatically assumed that i have an anxiety disorder and that i can't cope with stress!

becks x x x

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Thanks for this article. If I don't tell new doctors that former doctors used the a-word, they seem to listen better to the actual symptoms.

Someone posted an article a while back about "anxiety sensitivity" and POTS and it said that when you take out the tachycardia, POTS patients have less anxiety than other people. If anyone wants the link and cannot find it, I saved it in some logical place.


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