What is Postural Orthostatic Tachycardia Syndrome (POTS)?

Postural Orthostatic Tachycardia Syndrome (POTS)

Postural Orthostatic Tachycardia Syndrome (POTS) is a clinical syndrome characterized by a sustained heart rate increase of ≥30 bpm (or ≥40 bpm in those 12-19 years old) within 10 minutes of standing, absence of orthostatic hypotension, and frequent symptoms of orthostatic intolerance that persist for at least 3 months. 1

Diagnostic Criteria

POTS is diagnosed based on the following specific criteria:

1. Heart rate increase:

   • ≥30 bpm increase within 10 minutes of standing in adults
   • ≥40 bpm increase in adolescents aged 12-19 years 2, 1

2. Blood pressure response:

   • Absence of orthostatic hypotension (no sustained systolic blood pressure drop of ≥20 mm Hg) 2

3. Symptom profile:

   • Frequent symptoms of orthostatic intolerance during standing with improvement upon returning to supine position
   • Common symptoms include lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, and fatigue 2, 1

4. Duration:

   • Symptoms present for at least 3 months 2

5. Exclusion criteria:

   • Absence of other conditions explaining sinus tachycardia such as:
     • Anorexia nervosa
     • Primary anxiety disorders
     • Hyperventilation
     • Anemia
     • Fever, pain, infection
     • Dehydration
     • Hyperthyroidism
     • Pheochromocytoma
     • Use of cardioactive drugs
     • Severe deconditioning from prolonged bed rest 2

Pathophysiology

POTS is heterogeneous with three primary phenotypes identified:

1. Hyperadrenergic POTS:

   • Characterized by excessive norepinephrine production or impaired reuptake
   • Results in sympathetic overactivity 3

2. Neuropathic POTS:

   • Impaired vasoconstriction during orthostatic stress
   • Often involves peripheral sympathetic denervation 3

3. Hypovolemic POTS:

   • Associated with reduced blood volume
   • Often triggered by dehydration and physical deconditioning 3

Clinical Presentation

Patients with POTS typically present with:

• Dizziness and lightheadedness upon standing
• Rapid heartbeat and palpitations
• Weakness and fatigue
• Physical deconditioning and reduced exercise capacity
• Headache and "brain fog" (cognitive difficulties)
• Dyspnea
• Gastrointestinal symptoms
• Musculoskeletal pain 4

Common Triggers and Associations

POTS onset is often precipitated by:

• Viral infections (including COVID-19)
• Vaccination
• Trauma
• Pregnancy
• Surgery
• Psychosocial stress 4, 5

Post-COVID POTS

Recent evidence indicates that 2%-14% of COVID-19 survivors develop POTS, with 9%-61% experiencing POTS-like symptoms within 6-8 months of SARS-CoV-2 infection. This specific form of POTS is now recognized as part of post-acute COVID-19 syndrome (PASC POTS) 2, 5.

Management Approach

Management of POTS focuses on:

1. Non-pharmacological interventions (first-line for all patients):

   • Increased salt intake (10-12g daily)
   • Increased fluid intake (2-3 liters daily)
   • Compression garments for lower extremities
   • Gradual, structured exercise program
   • Avoiding triggers 1, 6

2. Pharmacological therapy (tailored to phenotype):

   • Note: No FDA-approved medications specifically for POTS 6
   • Hyperadrenergic POTS: Low-dose beta-blockers
   • Neuropathic POTS: Midodrine, pyridostigmine
   • Hypovolemic POTS: Fludrocortisone for volume expansion 3

Prognosis

Although long-term prognosis is not well-established, approximately 50% of patients spontaneously recover within 1-3 years. However, many patients experience persistent symptoms that can significantly impact quality of life 4.

Key Clinical Considerations

• POTS predominantly affects females (≈80%) between 15-45 years old
• Prevalence ranges from 0.2% to 1.0% in developed countries
• Diagnostic testing should include head-up tilt test with non-invasive beat-to-beat hemodynamic monitoring
• POTS can be mistaken for anxiety disorders or deconditioning
• A multidisciplinary approach involving cardiology, neurology, and rehabilitation medicine often yields the best outcomes 4, 6