Efficacy and safety of low dose propranolol versus diltiazem in the prophylaxis of supraventricular tachyarrhythmia after coronary artery bypass grafting

Objective. Supraventricular tachyarrhythmias (SVT) complicate postoperative management after coronary bypass surgery in about 30% of all patients. Though a prophylactic treatment both with P-adrenergic blocking agents and the calcium antagonist diltiazem has been used for the prevention of post-operative SVT, no study yet has per formed a prospective comparison of the efficacy of these therapies. Methods. To investigate the prophylactic effect of either a calcium antagonist (diltiazem, 0.1 mg/kg per h i.v.) or a beta-adrenergic blocking agent (propranolol, 10 mg every 6 h postoperatively), we randomized prospectively 103 consecutive patients into three groups, the third one serving as a control group, Anti-arrhythmic medication was started with the procedure and was continued until the 3rd postoperative day. Results. Preoperative conditions were the same for the three groups concerning age, extent of coronary heart disease, ventricular Function and heart-related medication. There were no differences in intraoperative parameters or postoperative enzyme patterns. Diltiazem was ineffective in preventing SVT, the incidence being exactly the same as in the control group (35%). Propranolol reduced the occurrence of SVT significantly (7%. P < 0.05). Furthermore, patients treated with diltiazem needed positive inotropic support more often in the first hours after surgery than patients of the control group (30% vs 5%, P < 0.01). Conclusions. The perioperative administration of low-dose propranolol is considered a safe and effective drug prophylaxis to avoid the occurrence of SVT after bypass surgery.