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Neurology. 2013 May 21;80(21):1927-33. doi: 10.1212/WNL.0b013e318293e310. Epub 2013 Apr 24.

Low-dose propranolol and exercise capacity in postural tachycardia syndrome: a randomized study.

Author information

1
Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA.

Abstract

OBJECTIVE:

To determine the effect of low-dose propranolol on maximal exercise capacity in patients with postural tachycardia syndrome (POTS).

METHODS:

We compared the effect of placebo vs a single low dose of propranolol (20 mg) on peak oxygen consumption (VO2max), an established measure of exercise capacity, in 11 patients with POTS and 7 healthy subjects in a randomized, double-blind study. Subjects exercised on a semirecumbent bicycle, with increasing intervals of resistance to maximal effort.

RESULTS:

Maximal exercise capacity was similar between groups following placebo. Low-dose propranolol improved VO2max in patients with POTS (24.5 ± 0.7 placebo vs 27.6 ± 1.0 mL/min/kg propranolol; p = 0.024), but not healthy subjects. The increase in VO2max in POTS was associated with attenuated peak heart rate responses (142 ± 8 propranolol vs 165 ± 4 bpm placebo; p = 0.005) and improved stroke volume (81 ± 4 propranolol vs 67 ± 3 mL placebo; p = 0.013). In a separate cohort of POTS patients, neither high-dose propranolol (80 mg) nor metoprolol (100 mg) improved VO2max, despite similar lowering of heart rate.

CONCLUSIONS:

These findings suggest that nonselective β-blockade with propranolol, when used at the low doses frequently used for treatment of POTS, may provide a modest beneficial effect to improve heart rate control and exercise capacity.

CLASSIFICATION OF EVIDENCE:

This study provides Class II evidence that a single low dose of propranolol (20 mg) as compared with placebo is useful in increasing maximum exercise capacity measured 1 hour after medication.

PMID:
23616163
PMCID:
PMC3716342
DOI:
10.1212/WNL.0b013e318293e310
[Indexed for MEDLINE]
Free PMC Article

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