The antiarrhythmic efficacy of oral
acebutolol, a new cardioselective beta-blocking agent, was assessed in a randomized double-blind, placebo-controlled study. Twenty-five patients with greater than or equal to 30
ventricular ectopic beats (VEB) per hour on three control ambulatory monitorings were studied. Mean VEB reduction from the control period was 35% with placebo and 45% and 50% with the use of
acebutolol 200 mg and 400 mg, respectively. Eleven patients had greater than or equal to 70% reduction in VEB with
acebutolol and nine of them had greater than or equal to 90 VEB reduction. Among these 11 patients, the mean VEB suppression was 51% after placebo but significantly higher following the two doses of
acebutolol at 71% (p less than 0.05) and 86% (p less than 0.01). The mean reduction of paired VEB compared to placebo was 71% (p less than 0.05) and 75% (p less than 0.01) following 200 mg and 400 mg of
acebutolol and only 49% after placebo. Complete suppression of paroxysmal
ventricular tachycardia was also noted in five patients. Mean PR interval only increased slightly when patients took 400 mg of
acebutolol, but there was no significant change in either the QRS or QTc intervals. A significant decrease in heart rate from that during control periods was noted after
acebutolol. No significant adverse reactions were noted during the study.
Acebutolol appears to be an effective and well-tolerated antiarrhythmic agent in the treatment of VEB and higher grades of ventricular ectopy.