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Postural orthostatic tachycardia syndrome (POTS) is a disorder in which sustained tachycardia — but not hypotension — and various other symptoms occur upon standing. In this report, Mayo Clinic researchers review 152 cases seen over an 11-year period.
Patients were predominantly female (87%) and young (mean age, 30). The mean heart rate increase to head-up tilt was 44 beats per minute. Common symptoms upon standing included lightheadedness, weakness, palpitations, and tremulousness. Heat or exercise tended to exacerbate symptoms. Many patients also reported generalized symptoms such as fatigue and sleep disturbance. One third of patients had mild-to-moderate abnormalities of autonomic function, particularly on tests that suggest peripheral postganglionic sympathetic denervation in the legs. One third of patients had elevated plasma norepinephrine levels on standing.
Thieben MJ et al. Postural orthostatic tachycardia syndrome: The Mayo Clinic experience. Mayo Clin Proc 2007 Mar; 82:308-13.
Comment
The cause of POTS remains uncertain, but it is likely a heterogeneous disorder with demonstrable peripheral autonomic dysfunction in some cases (see Journal Watch Oct 13 2000). Proposed treatments include volume expansion (e.g., with fluids or fludrocortisone), β-blockers, and midodrine.