Beta-Blockers for Postural Tachycardia Syndrome?

Postural tachycardia syndrome (POTS) is characterized clinically by sustained tachycardia upon standing that is not related to medical conditions or medications. The underlying cause of POTS is unclear, although several mechanisms have been proposed, such as sympathetic activation, hypovolemia, or deconditioning. To test the effect of beta-blockade in POTS, researchers conducted a randomized, double-blind, crossover study assessing the effect of a single oral low dose of propranolol (20 mg) versus placebo on exercise capacity measured by peak oxygen consumption (VO₂max) in 11 patients with POTS and 7 healthy volunteers. As a secondary objective, the authors compared VO₂max with high-dose propranolol (80 mg) versus placebo in a separate coho…