The use of off-pump coronary artery bypass grafting (CABG) has become widespread, since it has proven less invasive and to promote early recovery. In this study, we investigated the efficacy of off-pump CABG in patients in the evolving phase of acute myocardial infarction.Retrospective chart review was carried out for patients undergoing urgent isolated off-pump and on-pump CABG at Shin-Tokyo Hospital Group between January 1991 and June 2001. The patients' demographic, operative data, and postoperative results were collected.The off-pump group consisted of 19 males and 11 females with a mean age of 72.0 years and the on-pump group of 91 males and 38 females with a mean age of 64.3 years. Preoperative use of intraaortic balloon pumping and preoperative shock was more frequently observed in the on-pump group. The mean number of distal anastomoses was 3.1 +/- 0.9 in the off-pump group and 3.2 +/- 1.1 in the on-pump group (p = NS). Intubation time (18.5 vs 32.9 hours), ICU stay (3.4 vs 4.9 days), and postoperative stay (13.5 vs 24.3 days) were significantly shorter in the off-pump group than in the on-pump group (P < 0.05). The frequency of the major complications was significantly lower in the off-pump group (9/30, 30%) than the on-pump group (65/129, 50.4%), especially for postoperative low output syndrome (p < 0.05). Multivariate analysis demonstrated a significant reduction in the recovery period by use of off-pump CABG. Early follow-up results were similar between the two groups, in terms of late cardiac events and survival.Urgent off-pump CABG is safe and provides early recovery, provided that the patient's intraoperative hemodynamics are taken into account.