Effects of Acebutolol, a New Beta-receptor Blockade, on Premature Ventricular Contractions

The present study describes the anti-arrhythmic action of acebutolol, a new relatively cardioselective beta-adrenergic antagonist, on 19 patients with premature ventricular contractions, that was assessed with 24 hour ambulatory ECG monitoring. Total heart rate numbers in 24 hours were significantly reduced to 87% and 88% of control levels with 300 mg and 600 mg of acebutolol, respectively. While 300mg of acebutolol revealed significant reduction of total PVCs in 24 hours to 79% of control, 600mg of acebutolol did not show significant suppression of PVCs. As a group, diurnal variation of PVC revealed spontaneous reduction around noon and during sleep.Acebutolol, 300 mg/day, was effective in suppressing PVCs from 6 p.m. to 1 a.m. with average reduction of 43% . Double dose of acebutolol, 600 mg/day, was less effective and suppressed them only between 8 p.m. to 10 p.m. Plasma concentration of acebutolol measured by Collins' method did not correlate with the anti-arrhythmic effect of acebutolol . In conclusion, acebutolol, 300 mg/day was found to be effective in suppressing PVCs and was well tolerated without unmanageable adverse symptoms.