Prevention by acebutolol of rhythm disorders following coronary bypass surgery

Seventy-one patients submitted routinely to coronary artery bypass surgery were randomized into 2 groups. Group A (32 patients) received 24 hr after initiation of surgery an intravenous perfusion of 100 mg of acebutolol given over 24 hr (22 cases) or 600 mg administered orally (10 cases). On subsequent days, they received 1200 mg of acebutolol/day orally. Group B (39 patients) was used as control. The groups were comparable in terms of age, sex, severity of coronary disease, preoperative therapy, duration of extracorporeal circulation, aortic clamping time, and immediate postoperative haemodynamic findings. No patient received digitalis. During hospital stay (10 days), 1 group A patient (3%) and 13 group B patients (33%; P less than 0.001) developed a sustained episode of atrial arrhythmia (fibrillation, flutter or atrial ectopic tachycardia). The majority of these rhythm disorders developed between days 2 and 4. On Holter monitoring on days 7-10, malignant ventricular extrasystoles (grades IV and V of Lown's classification) were more frequent in group B (65.2%) than in group A (19.3%; P less than 0.001). Haemodynamic measurements taken at rest performed in 27 patients on days 7-10 (16 patients of group A; 11 of group B). No difference was observed between the two groups. Acebutolol is a safe and efficacious drug for the prevention of arrhythmias following coronary surgery.