ANS Dysfunction in adolescents with POTS & CFS

[briarrose]

I was doing a little research on the hair thing and came across this and I didn't know whether to be mad or laugh. Please read after # 2,7 under introduction!

It mentions that the adolescent POTS patients fail to meet the criteria for CFS.

Give me a break and come up to speed with POTS please CDC!!!

If you would like to read this article in it's entirety please see

http://www.pedresearch.org/cgi/content/full/48/2/218

ABSTRACT

The objective was to determine the nature of autonomic and vasomotor changes in adolescent patients with orthostatic tachycardia associated with the chronic fatigue syndrome (CFS) and the postural orthostatic tachycardia syndrome (POTS). Continuous electrocardiography and arterial tonometry was used to investigate the heart rate and blood pressure responses before and 3?5 min after head-up tilt in 22 adolescents with POTS and 14 adolescents with CFS, compared with control subjects comprising 10 healthy adolescents and 20 patients with simple faint. Heart rate and blood pressure variability, determined baroreceptor function using transfer function analysis, and measured cardiac vagal and adrenergic autonomic responses were calculated using timed breathing and the quantitative Valsalva maneuver. Two of 10 healthy controls and 14 of 20 simple faint patients experienced vasovagal syncope during head-up tilt. By design, all CFS and POTS patients experienced orthostatic tachycardia, often associated with hypotension. R-R interval and heart rate variability were decreased in CFS and POTS patients compared with control subjects and remained decreased with head-up tilt. Low-frequency (0.05?0.15 Hz) blood pressure variability reflecting vasomotion was increased in CFS and POTS patients compared with control subjects and increased further with head-up tilt. This was associated with depressed baroreflex transfer indicating baroreceptor attenuation through defective vagal efferent response. Only the sympathetic response remained. Heart rate variability declined progressively from normal healthy control subjects through syncope to POTS to CFS patients. Timed breathing and Valsalva maneuver were most often normal in CFS and POTS patients, although abnormalities in select individuals were found. Heart rate and blood pressure regulation in POTS and CFS patients are similar and indicate attenuated efferent vagal baroreflex associated with increased vasomotor tone. Loss of beat-to-beat heart rate control may contribute to a destabilized blood pressure resulting in orthostatic intolerance. The dysautonomia of orthostatic intolerance in POTS and in chronic fatigue are similar.

Abbreviations:

CFS, chronic fatigue syndrome

POTS, postural orthostatic tachycardia syndrome

HUT, head-up tilt

CDC, Centers for Disease Control and Prevention

BP, blood pressure

LF, low frequency

HF, high frequency

VLF, very low frequency

HRV, heart rate variability

INTRODUCTION

Orthostatic intolerance is defined by the inability to remain upright without severe signs and symptoms such as hypotension, tachycardia, lightheadedness, pallor, fatigue, weakness, and nausea. Orthostatic intolerance appears in many guises including overt dysautonomia, vasovagal syncope, and orthostatic tachycardia (1). POTS is operationally defined by the presence of symptoms of orthostatic intolerance associated with an increase in sinus heart rate of >30 beats/min or to a rate of >120 beats/min during the first 10 min of HUT table testing (2). Previous work, including our own, has suggested that adolescent patients with CFS often have findings of POTS during HUT (3?6). Conversely, patients with POTS often have fatigue as a prominent clinical feature (2, 7). Recent data have shown that adolescent patients with POTS share many symptoms with those having CFS, yet fail to satisfy the CDC criteria for that illness (8). Those criteria, which define the illness, are all symptom-related and include chronic debilitating fatigue lasting for 6 mo associated with cognitive difficulties, pharyngitis, tender lymphadenopathy, muscle pain, joint pain, headache, sleep disturbance, and postexercise malaise unexplained by other illness. POTS children are usually less symptomatic, miss fewer school days, and generally recover within a matter of months (9). Prior studies showed a reduction in HRV consistent with either global autonomic dysfunction or vagal withdrawal (5, 6). However, lack of consistent autonomic testing and continuous BP recordings prohibit drawing conclusions concerning mechanism. To remedy this, the present studies were conducted to address the following questions:

1. Is there autonomic dysfunction in adolescent patients with orthostatic tachycardia?

2. Does this relate to patients? adaptation to orthostatic stress in the form of HUT?

3. What is the mechanism by which this alters the adaptation to orthostatic stress? Is there vagal withdrawal, sympathetic dysfunction, or some combination of both? Does this translate into altered baroreceptor function?

In the present investigation, data before and during HUT are presented for two groups of patients with orthostatic tachycardia: patients referred for the evaluation of CFS and fulfilling the CDC criteria for the syndrome, and patients with orthostatic intolerance and POTS. Data from these patients are compared with data from normal healthy control subjects and from patients with multiple episodes of simple faint using standard tests of autonomic function and measurements of HRV, BP variability, and cross-spectral analysis to assess baroreceptor function.