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.