941-18 Antiarrhythmic Effect of Long-term β-Blocker Therapy for Dilated Cardiomyopathy on Survival Rate

To clarify how the long-term β-blocker (β) therapy for the patients (pts) with dilated cardiomyopathy (DCM) improves the rate of freedom from cardiac death (RFCD), 57 DCM pts with β (metoprolol; 40–60 mg/day)(G-l, followup; 6–120 M) and 72 DCM pts without β (G-2, follow-up; 6–102 M) were followed up. The survival was confirmed by annual interview. The cause of death and the preterminal condition of the pts were obtained from family members, medical personnel or medical recordings. The RFCO was analyzed with Kaplan-Meier life table method. At entry, there were no significant differences in age, sex, blood pressure, heart rate, left ventricular end-diastolic dimension (64.0 ± 6.0 vs 63.5 ± 6.8 mm) and ejection fraction (40.7 ± 9.1 vs 42.3 ± 8.3%) measured by echocardiography, and the severity of ventricular arrhythmia by 24 hours Holter monitoring (according to the Lawn's grade) between G-l and G-2. During the follow-up period, non-cardiac death occurred in 2 pts in G-1 and in 3 pts in G-2. The annual RFCD were calculated as shown below; 1Y 2Y 3Y 4Y 5Y 6Y 7Y G-1 1.0 * 1.0 # 0.98 * 0.98 # 0.98 # 0.98 # 0.87 * G-1 0.91 0.86 0.84 0.84 0.72 0.62 0.62 * p l 0.05 # P l 0.01 vs G-2 The number of death from heart failure did not show significant difference between G-1 (3 of 57 pts) and G-2 (4 of 72 pts). On the other hand, sudden death has occurred more often in G-2 (10 of 72 pts) than in G-1 (1 of 57 pts) (p l 0.05), resulting in that the RFCD was significantly better in G-l than in G-2. These results indicate that the long-term β-blocker therapy for DCM might improve the rate of freedom from cardiac death due to prevention of sudden death rather than of death from heart failure.