Postural orthostatic tachycardia syndrome

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Contents

Introduction

Postural orthostatic tachycardia syndrome (POTS, postural tachycardia syndrome, chronic orthostatic intolerance,"Grinch syndrome"[1]) is an underdiagnosed condition whose underlying mechanisms and effective therapy are often ill understood. It can overlap with chronic fatigue syndrome[2], be found (and be a major course of symptoms) in conditions as diverse as multiple sclerosis[3] and peripartum cardiomyopathy[4]. The presentation can be modified by coexisting conditions such as joint hypermobility[5]. A key point revealed by cranial perfusion studies appears to be cerebral hypoperfusion at the time of symptoms[6]. Spaceflight has forced a reevaluation by those who were biased by the more traditional presentations.

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  • Autonomic dysfunction
  • Tachycardia on standing
  • Reduced Blood pressure
  • Presyncope/syncope

Definition

More than 6 months symptomatic orthostatic intolerance accompanied by a heart rate rise of greater than or equal to 30 beats per minute (or a rate that exceeds 120 beats per minute) occurring within the first 10 minutes of standing or head-up tilt, without any evidence of orthostatic hypotension (a fall in blood pressure of greater than 20mmHg systolic/10 mmHg diastolic) not associated with other chronic debilitating conditions such as prolonged bed rest or medications known to diminish vascular or autonomic tone[7]. A further subdivision has been suggested into:

  1. Neuropathic POTS (partial dysautonomic)
    • Neuropathy preferentially involving the lower extremities with resultant venous pooling so more likely with diabetes or other neurological conditions
  2. Hyperadrenergic POTS
    • About 10% of POTS
    • Increase in systolic blood pressure of greater than or equal to 10 mmHg during head up tilt with concomitant tachycardia or serum norepinephnrine level greater than 600 pg/mL upon standing[8].
Hyperadrenergic POTS on 70 degrees head up tilt

Epidemiology

The vast majority are premenopausal women (typically in series a 5:1 female/male ratio). Severe cases result in unemployment, school absence, or reduced involvement in recreational activities. The sex differences of orthostatic tolerance become more dramatic after spaceflight or bed rest, in which “deconditioning” occurs. Microgravity exposure can elicit a “POTS-like” syndrome even in healthy fit individuals[9].

Aetiology

Cerebral hypoperfusion at the time of symptoms has been postulated as the common pathway[6] with hypocapnic cerebrovascular constriction, and impaired autoregulation[10]. A number of precipitating pathologies have been described with not infrequently the condition continuing after the original illness. That the dysautonomia in POTS and in chronic fatigue syndrome are similar has long been known[11] and indeed clinicians may confuse the condition with the later. There is fair evidence of reduced blood volume with paradoxically unchanged plasma renin activity and low aldosterone given the marked reduction in plasma volume.Some patients have inappropriately high plasma angiotensin II levels[12]. There is usually a red blood cell volume deficit[13]. Syncope may be related to greater reduction in blood volume[14]. Peripheral denervation, hypovolaemia, venous pooling, beta-receptor supersensitivity, and impairment of brain stem regulation are all implicated. Somatic hypervigilance and psychologic factors are involved in a significant proportion of patients[15] which may impair diagnosis. The phase of the menstrual cycle is associated[16].

Presentation

Frequently:

  • Palpitations
  • Presyncope (Syncope is definitely possible and a subgroup can have marked nodal arrest after prolonged head up tilt maintained for more than 10 minutes of POTS symptoms[17])
  • Fatigue
  • Orthostatic intolerance
  • Exercise intolerance
  • Dizziness
  • Headache
  • Mental clouding

Occasionally other dysautonomic symptoms such as gastrointestinal or sudomotor dysfunction.

Treatment

Hyperadrenergic POTS seems more difficult to treat successfully. Low dose beta blockers[18] are usually used first line although exercise therapy is more effective[19].

Lifestyle

Based on the hypothesis that the condition is usually associated with a small heart and reduced blood volume, exercise training appears effective [1]. High salt diet, copious fluids, and postural training have long been recommended[20].

Medical therapy

Case reports and small series suggest responses to:

Surgery

There have been recommendations of caesarian sections in pregnancy. There is actually no evidence for this as pregnancy is tolerated with no risk over controls[25].

References

  1. a b Fu Q, Vangundy TB, Galbreath MM, Shibata S, Jain M, Hastings JL, Bhella PS, Levine BD. Cardiac origins of the postural orthostatic tachycardia syndrome. Journal of the American College of Cardiology. 2010 Jun 22; 55(25):2858-68.(Link to article – subscription may be required.)
  2. Hoad A, Spickett G, Elliott J, Newton J. Postural orthostatic tachycardia syndrome is an under-recognized condition in chronic fatigue syndrome. QJM : monthly journal of the Association of Physicians. 2008 Dec; 101(12):961-5.(Link to article – subscription may be required.)
  3. Kanjwal K, Karabin B, Kanjwal Y, Grubb BP. Autonomic dysfunction presenting as postural orthostatic tachycardia syndrome in patients with multiple sclerosis. International journal of medical sciences. 2010; 7:62-7.(Epub)
  4. Kimpinski K, Iodice V, Low PA. Postural Tachycardia Syndrome associated with peripartum cardiomyopathy. Autonomic neuroscience : basic & clinical. 2010 Jun 24; 155(1-2):130-1.(Link to article – subscription may be required.)
  5. Kanjwal K, Saeed B, Karabin B, Kanjwal Y, Grubb BP. Comparative clinical profile of postural orthostatic tachycardia patients with and without joint hypermobility syndrome. Indian pacing and electrophysiology journal. 2010; 10(4):173-8.(Epub)
  6. a b Ocon AJ, Medow MS, Taneja I, Clarke D, Stewart JM. Decreased upright cerebral blood flow and cerebral autoregulation in normocapnic postural tachycardia syndrome. American journal of physiology. Heart and circulatory physiology. 2009 Aug; 297(2):H664-73.(Link to article – subscription may be required.)
  7. Low PA, Opfer-Gehrking TL, Textor SC, Benarroch EE, Shen WK, Schondorf R, Suarez GA, Rummans TA. Postural tachycardia syndrome (POTS). Neurology. 1995 Apr; 45(4 Suppl 5):S19-25.
  8. Kanjwal K, Saeed B, Karabin B, Kanjwal Y, Grubb BP. Clinical presentation and management of patients with hyperadrenergic postural orthostatic tachycardia syndrome. A single center experience. Cardiology journal. 2011; 18(5):527-31.
  9. Waters WW, Ziegler MG, Meck JV. Postspaceflight orthostatic hypotension occurs mostly in women and is predicted by low vascular resistance. Journal of applied physiology (Bethesda, Md. : 1985). 2002 Feb; 92(2):586-94.(Link to article – subscription may be required.)
  10. Low PA, Novak V, Spies JM, Novak P, Petty GW. Cerebrovascular regulation in the postural orthostatic tachycardia syndrome (POTS). The American journal of the medical sciences. 1999 Feb; 317(2):124-33.
  11. Stewart JM. 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. Pediatric research. 2000 Aug; 48(2):218-26.
  12. Mustafa HI, Garland EM, Biaggioni I, Black BK, Dupont WD, Robertson D, Raj SR. Abnormalities of angiotensin regulation in postural tachycardia syndrome. Heart rhythm : the official journal of the Heart Rhythm Society. 2011 Mar; 8(3):422-8.(Link to article – subscription may be required.)
  13. Raj SR, Biaggioni I, Yamhure PC, Black BK, Paranjape SY, Byrne DW, Robertson D. Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Circulation. 2005 Apr 5; 111(13):1574-82.(Link to article – subscription may be required.)
  14. Sandroni P, Opfer-Gehrking TL, Benarroch EE, Shen WK, Low PA. Certain cardiovascular indices predict syncope in the postural tachycardia syndrome. Clinical autonomic research : official journal of the Clinical Autonomic Research Society. 1996 Aug; 6(4):225-31.
  15. Low PA, Sandroni P, Joyner M, Shen WK. Postural tachycardia syndrome (POTS). Journal of cardiovascular electrophysiology. 2009 Mar; 20(3):352-8.(Link to article – subscription may be required.)
  16. Fu Q, VanGundy TB, Shibata S, Auchus RJ, Williams GH, Levine BD. Menstrual cycle affects renal-adrenal and hemodynamic responses during prolonged standing in the postural orthostatic tachycardia syndrome. Hypertension. 2010 Jul; 56(1):82-90.(Link to article – subscription may be required.)
  17. Kanjwal K, Sheikh M, Karabin B, Kanjwal Y, Grubb BP. Neurocardiogenic syncope coexisting with postural orthostatic tachycardia syndrome in patients suffering from orthostatic intolerance: a combined form of autonomic dysfunction. Pacing and clinical electrophysiology : PACE. 2011 May; 34(5):549-54.(Link to article – subscription may be required.)
  18. Raj SR, Black BK, Biaggioni I, Paranjape SY, Ramirez M, Dupont WD, Robertson D. Propranolol decreases tachycardia and improves symptoms in the postural tachycardia syndrome: less is more. Circulation. 2009 Sep 1; 120(9):725-34.(Link to article – subscription may be required.)
  19. Fu Q, Vangundy TB, Shibata S, Auchus RJ, Williams GH, Levine BD. Exercise training versus propranolol in the treatment of the postural orthostatic tachycardia syndrome. Hypertension. 2011 Aug; 58(2):167-75.(Link to article – subscription may be required.)
  20. Low PA, Sandroni P, Joyner M, Shen WK. Postural tachycardia syndrome (POTS). Journal of cardiovascular electrophysiology. 2009 Mar; 20(3):352-8.(Link to article – subscription may be required.)
  21. Chen L, Wang L, Sun J, Qin J, Tang C, Jin H, Du J. Midodrine hydrochloride is effective in the treatment of children with postural orthostatic tachycardia syndrome. Circulation journal : official journal of the Japanese Circulation Society. 2011; 75(4):927-31.
  22. Hersi AS. Potentially new indication of ivabradine: treatment of a patient with postural orthostatic tachycardia syndrome. The open cardiovascular medicine journal. 2010; 4:166-7.(Epub) (Link to article – subscription may be required.)
  23. McDonald C, Frith J, Newton JL. Single centre experience of ivabradine in postural orthostatic tachycardia syndrome. Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology. 2011 Mar; 13(3):427-30.(Link to article – subscription may be required.)
  24. Raj SR, Black BK, Biaggioni I, Harris PA, Robertson D. Acetylcholinesterase inhibition improves tachycardia in postural tachycardia syndrome. Circulation. 2005 May 31; 111(21):2734-40.(Link to article – subscription may be required.)
  25. Kimpinski K, Iodice V, Sandroni P, Low PA. Effect of pregnancy on postural tachycardia syndrome. Mayo Clinic proceedings. Mayo Clinic. 2010 Jul; 85(7):639-44.(Link to article – subscription may be required.)
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