EFFICACY OF PROPAFENONE COMPARED WITH QUINIDINE IN CHRONIC VENTRICULAR ARRHYTHMIAS

A double-blind, randomized study was designed to evaluate the efficacy of oral propafenone and oral quinidine in suppressing premature ventricular complexes (PVC) in 25 men for 3 wk. Twelve were randomized to the quinidine group and 13 to the propafenone group. Small doses of the drugs were administered for 1 wk (200 mg of quinidine every 6 h or 300 mg of propafenone every 12 h) and large doses were administered for another week (400 mg of quinidine every 6 h or 300 mg of propafenone every 8 h). Strict criteria were used to define responders to antiarrhythmic therapy. For 85% reduction in total PVC per h: during the low-dose week, 36% in the quinidine group and 50% in the propafenone group were responders (while during the high-dose week 33% and 64% were responders. For > 95% reduction in ventricular couplets per hour: during the low-dose week, 45% in each group were responders, while during the high-dose week 56% and 60% were responders (NS). For 100% abolition of ventricular tachycardia (VT) beats per 24 h: during the low-dose week 60% in the quinidine group and 56% in the propafenone group were responders; during the high-dose week 80% and 67% were responders. There was no significant difference in the 2 groups in incidence of side effects. This study shows comparable efficacy and tolerance of propafenone and quinidine for the control of ventricular arrhythmias in ambulatory patients with diverse forms of heart diseases.