Effects of long-term β-blockade (metoprolol) therapy in patients with dilated cardiomyopathy

Abstract

Twenty-two patients with dilated cardiomyopathy (DCM) were treated with metoprolol and their clinical courses were compared with those of 26 patients untreated with β-blocking agents (non β group). Of the 22 patients treated with metoprolol, 19 (β group) were treated for a long period, 3 patients left the study within its first 6 months. Using the NYHA classification, 4 patients of the β group were evaluated as having clinically improved, while none was aggravated, excluding 2 cases of death which occurred during the follow up period. In the non-β group, clinical improvement was found for 2 patients and aggravation in functional class for 10. The left ventricular diameter was significantly decreased and parameters of systolic function and exercise tolerance were significantly improved in patients of the β group, while no such improvements occurred in patients of the non-β group. Twenty-four-hour ECG monitoring demonstrated a significant reduction in incidences of ventricular extrasystole in the β group but not in those of the non-β group. Improvement of arrhythmias, evaluated using Lown's grading system, was also identified more frequently in the β group than in the non β group. During the follow-up period, 2 patients of the β group and 10 patients of the non-β-group died. The survival curve for patients of the β group prepared using the Caplan Meier Method was better than that for patients of the non β group. Metoprolol was therefore found to be useful for treatment of DCM.