Digoxin and propranolol in the prophylaxis of dysrhythmias after coronary artery bypass grafting

Serious tachydysrhythmias occur in 10% to 30% of patients early after coronary artery bypass grafting (CABG). We studied the effects of digoxin and propranolol in preventing these dysrhythmias over the first week after CABG (average number of grafts, 2.7/patient). Consecutive patients (n = 179) undergoing CABG were randomized to a drug (group 1) or a control (group 2) group. Excluded were patients given digoxin before CABG and those with ejection fractions of less than 40%, those with dysrhythmias within 18 hr after CABG, those being pacer dependent, and those with low-output syndrome after CABG. Risk factors were comparable in both groups. Electrocardiographic examination showed perioperative myocardial infarction in five patients (2.8%). Digoxin (1 mg iv given over 24 hr, then 0.25 mg/day) and propranolol (10 mg given every 6 hr) were started 6 hr after CABG. Supraventricular dysrhythmias requiring treatment occurred in 3.4% of 89 group 1 patients and in 30% of 90 group 2 patients (p less than .001); ventricular dysrhythmias occurred in 1.1% of group 1 and 8.9% of group 2 patients (p less than .01). In this study, a regimen of post-CABG digoxin and propranolol significantly reduced the incidence of supraventricular and ventricular dysrhythmias without causing adverse reactions.