Ventricular arrhythmias in dilated cardiomyopathy: efficacy of amiodarone.

Sixty-five patients with dilated cardiomyopathy were studied by means of 24-hour ECG monitoring. Ventricular arrhythmias were present in 62 (95.4%), of whom 52 (80%) showed a complex form (multiform ventricular extrasystoles, pairs, and ventricular tachycardia). Forty-one patients, presenting with complex ventricular arrhythmias, received antiarrhythmic treatment with amiodarone (600 mg/day in the first week, 400 mg/day in the second week, and 200 to 400 mg/day chronically), and were then controlled with periodic 24-hour ambulatory monitoring. A significant reduction in the number of ventricular extrasystoles was seen in over 70% of patients during a 3-year period. There was also a significant decrease in the incidence of complex ventricular arrhythmias (particularly of ventricular tachycardia). Adverse effects were noted in 23 patients, but only four had to stop treatment. During the follow-up period, 19 patients died: 14 of heart failure, four of sudden death, and one of a noncardiac cause; all patients who died suddenly were not treated with amiodarone (p = 0.022). Complex ventricular arrhythmias are frequent in dilated cardiomyopathy and it is suggested that amiodarone is effective in short- and long-term control of these arrhythmias.