Effect of quinidine or procainamide versus no antiarrhythmic drug on sudden cardiac death, total cardiac death, and total death in elderly patients with heart disease and complex ventricular arrhythmias.

A prospective study correlated the effect of quinidine or procainamide versus no antiarrhythmic drug on sudden cardiac death, total cardiac death and total death in 406 elderly patients with heart disease and asymptomatic complex ventricular arrhythmias detected by 24-hour ambulatory electrocardiograms. Of 397 patients treated with quinidine, 184 (46%) developed adverse effects during the first 2 weeks of therapy and were given no further antiarrhythmic therapy. Of 9 patients treated with procainamide, 2 (22%) developed adverse effects during the first 2 weeks of therapy and were given no further antiarrhythmic therapy. Adverse effects developed during long-term therapy in 6 patients (2%) receiving quinidine and in 3 patients (33%) receiving procainamide. Mean follow-up was 24 +/- 15 months in both groups. Sudden cardiac death, total cardiac death and total death occurred in 21, 43 and 65% of patients receiving quinidine or procainamide, respectively, and in 23, 44 and 63% of patients receiving no antiarrhythmic drug, respectively (difference not significant). Survival by Kaplan-Meier analysis showed no significant difference between the 2 groups for sudden cardiac death, total cardiac death or total death through 4 years. Patients with abnormal left ventricular ejection fraction had a 3.4 times higher incidence of sudden cardiac death, a 2.4 times higher incidence of total cardiac death and a 1.4 times higher incidence of total death than patients with normal left ventricular ejection fraction. These data showed no significant difference in sudden cardiac death, total cardiac death or total death between patients treated with quinidine or procainamide or with no antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)