What is Postural Orthostatic Tachycardia Syndrome (POTS)?

Postural Orthostatic Tachycardia Syndrome (POTS)

Postural Orthostatic Tachycardia Syndrome (POTS) is a form of cardiovascular autonomic disorder characterized by orthostatic intolerance with an inappropriate tachycardia upon standing (heart rate increase ≥30 bpm or ≥40 bpm in those 12-19 years old) within 10 minutes, chronic symptoms lasting at least 3 months, and absence of orthostatic hypotension. 1

Diagnostic Criteria

• Heart rate increase ≥30 bpm (≥40 bpm in ages 12-19) within 10 minutes of standing
• Absence of orthostatic hypotension (no drop >20 mmHg in systolic BP)
• Chronic symptoms of orthostatic intolerance for at least 3 months
• Optimal diagnostic cutoffs:
  • Tilt test: 38 bpm heart rate increase
  • Active stand test: 29 bpm heart rate increase 1

Clinical Presentation

• Common symptoms:
  • Dizziness and lightheadedness upon standing
  • Weakness and fatigue
  • Rapid heartbeat and palpitations
  • "Brain fog" and cognitive difficulties
  • Exercise intolerance
  • Headaches
  • Gastrointestinal disturbances
  • Musculoskeletal pain 1, 2

Pathophysiology and Subtypes

POTS has three primary phenotypes, each with distinct mechanisms:

1. Neuropathic POTS:

   • Partial autonomic neuropathy affecting lower limbs
   • Impaired vasoconstriction during orthostatic stress
   • Venous pooling in lower extremities 1, 3

2. Hyperadrenergic POTS:

   • Excessive norepinephrine production or impaired reuptake
   • Sympathetic overactivity
   • Often presents with anxiety-like symptoms, tremor, and hypertension 1, 3, 4

3. Hypovolemic POTS:

   • Reduced blood volume
   • Often triggered by dehydration and physical deconditioning 1, 3, 4

Associated Conditions and Triggers

• Onset often precipitated by:

  • Viral infections (including COVID-19)
  • Vaccination
  • Trauma
  • Pregnancy
  • Surgery
  • Psychosocial stress 1, 2

• Common comorbidities:

  • Mast cell activation syndrome (MCAS) - 25.2% of MCAS patients have POTS
  • Hypermobile Ehlers-Danlos syndrome (hEDS) - 37.5% of hEDS patients report POTS
  • Autoimmune disorders
  • Chronic fatigue syndrome 1

Management Approach

Non-Pharmacological Interventions (First-Line)

• Fluid and salt intake:

  • Increase salt intake to 10-12g daily (unless contraindicated)
  • Maintain fluid intake of 2-3 liters daily
  • Caution in patients with cardiac dysfunction, heart failure, uncontrolled hypertension, or chronic kidney disease 1

• Compression garments:

  • Waist-high compression stockings (30-40 mmHg pressure) to reduce venous pooling 1

• Exercise program:

  • Begin with recumbent or semi-recumbent exercise (rowing, swimming, recumbent cycling)
  • Start with 5-10 minutes daily at a level allowing speech in full sentences
  • Gradually increase duration by approximately 2 minutes per day each week 1

Pharmacological Interventions (Phenotype-Specific)

• For Neuropathic POTS:

  • Midodrine: Start at 2.5mg three times daily, increase to 10mg three times daily as needed
  • Pyridostigmine: Enhances vascular tone 1, 3

• For Hyperadrenergic POTS:

  • Low-dose beta-blockers 1, 3, 4

• For Hypovolemic POTS:

  • Fludrocortisone: Enhances sodium retention and increases blood volume
  • Monitor electrolytes and renal function 1, 3

• For refractory cases:

  • Droxidopa: Beneficial in neurogenic orthostatic hypotension
  • Octreotide 1

Monitoring and Follow-up

• Monitor for supine hypertension when using midodrine
• Check electrolytes (sodium, potassium, magnesium) and renal function, especially for patients on fludrocortisone
• Follow-up testing every 3-6 months or when changing treatment regimens
• Immediate testing during significant symptom exacerbations 1

Prognosis

• POTS is not associated with increased mortality
• Approximately 50% of patients spontaneously recover within 1-3 years
• Most patients experience some degree of improvement with proper treatment 2, 5

Important Caveats

• Currently, there are no FDA-approved medications specifically for POTS treatment
• Evidence for many medications used to treat POTS is limited
• Consider Spontaneous Intracranial Hypotension (SIH) as a differential diagnosis in patients with orthostatic headaches 1, 6
• Patients should seek immediate medical attention for syncope, severe chest pain, sustained palpitations unrelieved by rest, shortness of breath at rest, or palpitations with altered mental status 1