POTS Syndrome

●The postural tachycardia syndrome (POTS) is defined as a form of orthostatic intolerance characterized by an excessive increase in heart rate that occurs on standing without arterial hypotension.

●The etiology of POTS is not clear, but the disorder may be heterogeneous. Abnormalities in autonomic regulation that may either be genetic or acquired are described. Proposed mechanisms include partial sympathetic denervation leading to discordant cardiac and vascular sympathetic control, hypovolemia and impairment of the renin-angiotensin-aldosterone system, venous abnormalities and baroreflex dysfunction.

●The clinical symptoms of POTS are varied and nonspecific, and include dizziness, lightheadedness, weakness, blurred vision, and fatigue upon standing. The orthostatic nature of the symptoms is the primary clue to the diagnosis.

●The diagnosis of POTS is established from the history and head-up tilt testing which demonstrates a heart rate increase of >30 bpm over baseline or to >120 bpm. Dehydration, prolonged bedrest, medications, and other dysautonomias should be excluded as etiologies.

●The optimal therapy of POTS is not established. Patients should avoid precipitating factors, and physical activity should be encouraged. We suggest volume repletion and fludrocortisone (0.05 to 0.2 mg per day) as the first line of therapy . Some patients may benefit from midodrine or beta blocking agents. Other therapies remain under investigation, and further confirmation of benefit is needed before they can be recommended.

Bhopalwala. H