Properties of acebutolol in twenty patients with cardiac arrhythmias.

Acebutolol (M & B 17,803 A), a new cardioselective beta-adrenergic blocking agent, was given intravenously to 20 selected patients with various cardiac arrhythmias. Cumulative doses ranging from 12.5 to 50 mg were moderately or highly effective in 4 out of 4 patients with sinus tachycardia, 2 out of 3 patients with premature atrial beats, 3 out of 4 patients with premature ventricular beats, 3 out of 5 patients with atrial fibrillation (one was converted to sinus rhythm) and in 2 out of 3 patients with atrial flutter. The drug was ineffective in one patient with atrial tachycardia. Mild systolic hypotension occured in two patients with recent myocardial infarction and there was some aggravation of a preexisting bronchospasm in a patient with congestive heart failure secondary to hyper-thyroidism. It was concluded that acebutolol is a cardioselective beta-blocker which by intravenous route may be useful in the treatment of selected cardiac arrhythmias.