Comparative efficacy of oral sotalol and procainamide in patients with chronic ventricular arrhythmias: a multicenter study.

In an open, randomized, crossover study, the efficacy of sotalol and procainamide was compared in 33 patients with frequent, chronic premature ventricular contractions (PVCs). A 75% reduction in PVCs/24 hours (two 24-hour recordings) was arbitrarily considered to constitute an adequate therapeutic effect. Sotalol was started at a dose of 160 mg once daily for 1 week, followed by a 24-hour recording. In the absence of any therapeutic effect, the same procedure was repeated with 320 mg, 480 mg, and 640 mg daily. Procainamide, 1 gm three times/day, was given or, if plasma concentrations were insufficient, 1.5 gm three times/day for 1 week. PVC control was obtained in 22 (67%) patients on sotalol, including all 12 with ischemic heart disease. Procainamide was successful in 13 (39%) patients. Effects on the number of attacks of ventricular tachycardia were achieved by both drugs in those patients where PVCs were reduced by at least 75%. Sotalol caused side effects in five patients, who therefore could not accept planned increases in dosage. Side effects were noted by 12 patients with procainamide. Nine patients responded to both drugs, seven to neither. Thirteen responded to sotalol only and four to procainamide only. We conclude that sotalol is a useful alternative to procainamide in controlling chronic PVCs, especially in patients with ischemic heart disease.