A double-blind, placebo-controlled crossover trial of nadolol and verapamil in mild and moderately symptomatic hypertrophic cardiomyopathy.

OBJECTIVES

The aim of this study was to determine whether therapy with a beta-adrenergic or calcium channel blocking agent can improve the functional capacity and quality of life of patients with mild or moderately symptomatic hypertrophic cardiomyopathy.

BACKGROUND

Both beta-blockers and calcium channel blockers may alleviate symptoms in hypertrophic cardiomyopathy, but previous studies have been performed in hospitalized patients or have been open studies without control subjects.

METHODS

A randomized, double-blind crossover trial of nadolol, verapamil and placebo, administered for periods of 4 weeks each, was performed in 18 patients with mild or moderately symptomatic hypertrophic cardiomyopathy (10 men, 8 women; mean age +/- SD 39 +/- 17 years). A detailed symptom assessment, bicycle exercise testing, echocardiography and Holter monitoring were performed in each period.

RESULTS

Two patients withdrew from the study owing to symptomatic sinus bradycardia during nadolol therapy. Neither drug improved maximal oxygen consumption (placebo 26 +/- 8, verapamil 23 +/- 6, nadolol 21 +/- 7 ml/kg per min; p = 0.1). Peak exercise work load was reduced by > or = 10 W in 13 patients (81%) during nadolol therapy and in 4 patients (25%) during verapamil therapy (p = 0.005, nadolol vs. verapamil). Despite the effects on exercise capacity, 13 patients (81%) preferred drug treatment (8 verapamil, 5 nadolol) over placebo (p = 0.001). Verapamil improved reported performance at work compared with nadolol (p = 0.01) and tended to improve other measures of health-related behavior and symptoms compared with nadolol and placebo.

CONCLUSIONS

In patients with mild or moderately symptomatic hypertrophic cardiomyopathy, exercise capacity was not improved by nadolol or verapamil, and individuals were more often impaired by nadolol than with verapamil. Nevertheless, many patients derived symptomatic benefit from drug therapy, especially with verapamil.