METHODS	Fifty patients referred for CABG and considered to be at high risk for postoperative AF on the basis of prolonged signal-averaged ECG P wave duration > 140 ms were randomized to receive either a 24-hour infusion of esmolol 6-18 hours after CABG , at an average dose 67 + / - 7 microg/kg/min , followed by oral beta-blockers versus oral beta-blockers only beginning on postoperative day 1 .\