PERSISTING EFFECT OF CA2-CHANNEL BLOCKERS ON LEFT-VENTRICULAR FUNCTION IN HYPERTROPHIC CARDIOMYOPATHY AFTER 14 YEARS TREATMENT()

Ca2+-channel blockers of the verapamil type have been reported to exer t a beneficial effect on clinical. symptoms and survival rates in hype rtrophic cardiomyopathy, The effects of verapamil have been attributed predominantly to an improved diastolic filling. It is unknown whether an effect on diastolic filling persists in these patients after long- term treatment. Fourteen patients (12 men, 2 women, median age fifty-o ne [thirty-two to fifty-five] years) with hypertrophic cardiomyopathy were included in the study, Patients had been treated with verapamil 2 40-480 mg/d or gallopamil. 150-200 mg/d for fourteen (seven to sevente en) years. The effect of a withdrawal of Ca2+-channel blockers on para meters of left ventricular diastolic function was evaluated at rest an d during exercise in patients with hypertrophic cardiomyopathy after l ong-term therapy. Investigations were performed at rest and during sup ine ergometric exercise during ongoing Ca2+-channel blocking therapy a nd after five (four to nine) days' withdrawal (control). Pulsed Dopple r echocardiography was used to record diastolic mitral flow profiles f rom an apical four-chamber view. Withdrawal of Ca2+-channel blockers o f the phenylalkylamine type after long-term treatment of hypertrophic cardiomyopathy resulted in a significant reduction of early diastolic inflow velocity at rest and during exercise. In conclusion, these resu lts indicate a persistent improvement of early diastolic filling by Ca 2+-channel blockers even after long-term treatment.