Long-term effect of verapamil in hypertrophic cardiomyopathy.

We studied the long-term effects of oral verapamil (240-720 mg) daily on 10 patients with hypertrophic cardiomyopathy. Symptomatic improvement of chest pain or shortness of breath occurred in all the patients although 4 deteriorated after 1 year. Side effects occurred in 3 patients. The electrocardiogram improved in 4 subjects. Quantitative echocardiography showed a significant (P less than 0.05) decrease in left ventricular contractility (% delta S decreased from 44 +/- 9 to 38 +/- 9, mean +/- SD), septal hypertrophy (1.6 +/- 0.5 to 1.4 +/- 0.5 cm) and % thickening of the left ventricular free wall (79 +/- 29 to 57 +/- 22). There was also moderate evidence of improvement in left ventricular compliance; mitral valve EF slope increased from 38 to 55 mm/sec and left atrial diameter decreased.