Comparison of acebutolol with propranolol, quinidine, and placebo: results of three multicenter arrhythmia trials.

Acebutolol was compared to placebo, propranolol, and quinidine for the suppression of chronic ventricular arrhythmia in three double-blind, randomized crossover studies. Patients averaged greater than or equal to 10 to 30 premature ventricular contractions (PVCs) per hour in the baseline periods. Compared to baseline in all three studies, acebutolol significantly (p less than 0.002 to p less than 0.001) reduced mean total PVCs and complex PVCs. In all measurements, acebutolol was superior to placebo (p less than 0.02 to p less than 0.001) and comparable to propranolol and quinidine. During acebutolol treatment, 39% of the patients had reductions of greater than or equal to 75% in mean hourly PVC frequency compared to 23% during placebo treatment (p = 0.02). Similar numbers of patients had greater than or equal to 75% reductions during acebutolol treatment in comparison with propranolol and quinidine. Acebutolol was better tolerated than quinidine and produced an antiarrhythmic effect equivalent to that of propranolol, with a significantly (p less than 0.01) lesser decrease in resting heart rate. The antiarrhythmic activity of acebutolol, its ancillary pharmacologic properties, and its tolerance by a diverse group of patients make acebutolol a significant tool for the clinician in the management of chronic arrhythmia.