What is Postural Orthostatic Tachycardia Syndrome (POTS)?
POTS is a chronic cardiovascular autonomic disorder characterized by an excessive heart rate increase of ≥30 bpm (≥40 bpm in adolescents aged 12-19 years) within 10 minutes of standing, occurring without orthostatic hypotension, accompanied by symptoms of orthostatic intolerance that improve when lying down. 1, 2
Core Diagnostic Criteria
POTS diagnosis requires all five components to be present simultaneously 2:
- Heart rate criteria: Sustained increase of ≥30 bpm within 10 minutes of standing (≥40 bpm for ages 12-19 years), with standing heart rate often exceeding 120 bpm 1, 2
- Blood pressure criteria: Explicit absence of orthostatic hypotension (no sustained systolic BP drop ≥20 mmHg or diastolic drop ≥10 mmHg within 3 minutes of standing) 1, 2, 3
- Symptom profile: Frequent symptoms of orthostatic intolerance during standing that rapidly improve upon returning to supine position, including lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, exercise intolerance, and fatigue 1, 2
- Duration requirement: Symptoms must persist for at least 3 months (6 months in children) 4, 1
- Exclusion criteria: Absence of other conditions explaining sinus tachycardia such as anorexia nervosa, primary anxiety disorders, hyperventilation, anemia, fever, pain, infection, dehydration, hyperthyroidism, pheochromocytoma, or use of cardioactive drugs 4, 1
Clinical Presentation and Demographics
POTS predominantly affects young women aged 15-45 years, with approximately 80% of patients being female. 5, 6 The onset is typically precipitated by immunological stressors such as viral infection, vaccination, trauma, pregnancy, surgery, or psychosocial stress 5, 6. The syndrome may be associated with recent infection, joint hypermobility syndrome, chronic fatigue syndrome, or severe deconditioning 2.
Common Symptoms Beyond Orthostatic Intolerance
Patients experience a constellation of symptoms that significantly impair quality of life 1, 5:
- Cardiovascular: Palpitations, sinus tachycardia, chest pain 1
- Neurological: Dizziness, lightheadedness, "brain fog," cognitive difficulties, headache 1, 5
- Visual: Blurred vision, tunnel vision 1
- Systemic: Fatigue, lethargy, generalized weakness, exercise intolerance 1, 5
- Gastrointestinal: Gastrointestinal dysfunction and distress 1, 5
- Musculoskeletal: Musculoskeletal pain 5
Syncope is rare in POTS and typically occurs only when vasovagal reflex activation is triggered, not from POTS itself. 2
Pathophysiology
The orthostatic tachycardia in POTS reflects convergence of multiple pathophysiological processes as a final common pathway 7. Three primary POTS phenotypes have been identified, each requiring tailored management 8:
- Hyperadrenergic POTS: Excessive norepinephrine production or impaired reuptake leads to sympathetic overactivity 8
- Neuropathic POTS: Partial sympathetic neuropathy resulting in impaired vasoconstriction during orthostatic stress 8
- Hypovolemic POTS: Central hypovolemia and reflex tachycardia, often triggered by dehydration and physical deconditioning 8
Additional proposed mechanisms include mast cell activation, immune-mediated processes, and deconditioning 7.
Prognosis and Natural History
POTS is not associated with mortality, and approximately 50% of patients spontaneously recover within 1-3 years after diagnosis. 5 Many patients improve to some degree over time with proper treatment 7. However, the most severely affected patients may remain handicapped despite treatment 5.
Prevalence
The prevalence of POTS ranges between 0.2% and 1.0% in developed countries 5. It represents one of the most common presentations of syncope and presyncope secondary to autonomic dysfunction in emergency rooms and in cardiology, neurology, and primary care clinics 7.
Post-COVID-19 POTS
POTS can develop as a post-acute sequela of COVID-19 (PASC POTS), defined as a clinical syndrome that started during probable or confirmed acute COVID-19 and lasts ≥3 months, meeting all standard POTS diagnostic criteria 4.