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 [+ or -] 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 election 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. The presence or absence of antiarrhythmic therapy did not affect the event risk regardless of left ventricular ejection fraction [is greater than or equal to] 50% versus (Am J Cardiol 1990;66:423-428)
The effects of the cardiovascular drugs quinidine and procainamide on sudden cardiac death, total cardiac death, and total death were assessed in 406 elderly patients with heart disease and ventricular arrhythmias (abnormal heart rhythms). Within the first two weeks of treatment, 184 of 397 patients treated with quinidine and 2 of 9 patients treated with procainamide developed adverse reactions and discontinued drug therapy. During long-term therapy, toxic effects developed in six patients treated with quinidine and three patients treated with procainamide. Patients were assessed over a 24-month period. The incidence of sudden cardiac death, total cardiac death, and total death was 21, 43, and 65 percent, respectively, in patients treated with antiarrhythmic agents and 23, 44, and 65 percent, respectively, in patients not receiving these agents. At four years there was no difference in survival between the two groups of patients. However, abnormal left ventricular ejection fraction (the proportion of blood emptied from the left heart ventricle at the end of a contraction) was associated with higher incidences of sudden cardiac death, total cardiac death, or total death through four years. The incidences of sudden cardiac death, total cardiac death, or total death were similar among patients who were and were not treated with these antiarrhythmic agents. These findings confirm that treatment with quinidine or procainamide did not alter the risks of sudden and total cardiac death and total death. In addition, the lack of effect of these antiarrhythmic agents on the risks of cardiac and total death was not influenced by abnormal left ventricular ejection fraction, ventricular arrhythmias, or ischemic heart disease. (Consumer Summary produced by Reliance Medical Information, Inc.)