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Postural (Orthostatic) Tachycardia Syndrome (POTS)

Postural (Orthostatic) Tachycardia Syndrome (POTS) is a topic covered in the 5-Minute Clinical Consult.

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Basics

Description

Clinical condition characterized by development of symptoms upon standing (e.g., postural light-headedness, weakness, and palpitations), associated with an increase in the heart rate (HR) of ≥30 beats/min in adults (>40 beats/min in children aged 12 to 19 years) in the absence of orthostatic hypotension (decrease in systolic blood pressure [BP] of 20 mm Hg and diastolic BP of 10 mm Hg) and symptoms associated with orthostatic intolerance (e.g., tachycardia, presyncope) persisting for 6 months (1)

Epidemiology

  • Formal epidemiologic studies have not been performed; however, the estimated prevalence in the United States is about 500,000 (2).
  • Female to male ratio is 5:1 (1).
  • Usual onset is between ages 15 and 25 years.

Etiology and Pathophysiology

Likely a disorder with multiple potential causes. A variety of mechanisms have been proposed, and more than one may coexist in these patients (1):

  • Hypovolemia: 70% of patients have a decreased plasma volume without a compensatory increase in plasma renin and aldosterone activity.
  • Peripheral autonomic denervation: Present in up to 50% of patients, this is characterized by decreased vasoconstriction in the extremities and splanchnic vessels, resulting in venous blood pooling.
  • Increased sympathetic tone (hyperadrenergic): This is seen in up to 50% of patients. Patients with this mechanism usually experience an increase of ≥10 mm Hg in the systolic BP upon standing and sympathetic symptoms, such as palpitations, anxiety, and tremors, due to increase in circulating catecholamines and adrenergic hypersensitivity.
  • Cardiovascular deconditioning: Some of these patients have reduced left ventricular mass, stroke volume, blood volume, and oxygen uptake. It is uncertain whether deconditioning is a contributing cause or consequence of postural (orthostatic) tachycardia syndrome (POTS).
  • Autoimmune hypothesis: Some studies have isolated autoantibodies that target receptors of the autonomic nervous system in POTS patients. Specifically, IgG from POTS patients have been shown to activate β1 and β2 receptors and simultaneously partially block the vasoconstrictive α1 adrenoceptor. These findings support the notion that POTS may be an autoimmune condition elicited in genetically susceptible individuals by an immunogenic trigger (2).
Genetics

Most cases of POTS are sporadic; however, some patients have family history of orthostatic intolerance, which suggests a certain degree of heritability. Some of the genetic markers associated with this condition are:

  • Mutations of SLC6A2 (norepinephrine [NE] transporter gene), involved in NE uptake at the synaptic cleft
  • Polymorphisms of NOS3 (nitric oxide synthase gene)
  • Polymorphisms of ADRB2 (β2 receptor gene)

Risk Factors

No specific risk factors have been described.

General Prevention

No strategies for prevention have been described. However, patients with a history of POTS should avoid dehydration. Furthermore, such individuals may benefit from regular physical activity.

Commonly Associated Conditions

  • Chronic fatigue syndrome
  • Mitral valve prolapse
  • Mast cell activation abnormalities
  • Ehlers-Danlos syndrome
  • Multiple sclerosis
  • Hypermobility syndrome
  • Fibromyalgia
  • Visceral pain and dysmotility
  • Chronic headaches
  • Anxiety disorders
  • Other autoimmune diseases (Sjögren syndrome, celiac disease, Hashimoto thyroiditis, systemic lupus, etc.)

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Citation

Stephens, Mark B., et al., editors. "Postural (Orthostatic) Tachycardia Syndrome (POTS)." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2019. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816820/all/Postural__Orthostatic__Tachycardia_Syndrome__POTS_.
Postural (Orthostatic) Tachycardia Syndrome (POTS). In: Stephens MB, Golding J, Baldor RA, et al, eds. 5-Minute Clinical Consult. 27th ed. Wolters Kluwer; 2019. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816820/all/Postural__Orthostatic__Tachycardia_Syndrome__POTS_. Accessed June 16, 2019.
Postural (Orthostatic) Tachycardia Syndrome (POTS). (2019). In Stephens, M. B., Golding, J., Baldor, R. A., & Domino, F. J. (Eds.), 5-Minute Clinical Consult. Available from https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816820/all/Postural__Orthostatic__Tachycardia_Syndrome__POTS_
Postural (Orthostatic) Tachycardia Syndrome (POTS) [Internet]. In: Stephens MB, Golding J, Baldor RA, Domino FJ, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2019. [cited 2019 June 16]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816820/all/Postural__Orthostatic__Tachycardia_Syndrome__POTS_.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Postural (Orthostatic) Tachycardia Syndrome (POTS) ID - 816820 ED - Stephens,Mark B, ED - Golding,Jeremy, ED - Baldor,Robert A, ED - Domino,Frank J, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816820/all/Postural__Orthostatic__Tachycardia_Syndrome__POTS_ PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -