Intermittent antegrade warm blood cardioplegia has been used routinely at our institution over the last 3 years. We report here a comparison between the first 250 consecutive patients undergoing elective coronary artery bypass grafting in which intermittent antegrade warm blood cardioplegia was used (group A) and the last 250 consecutive patients who received intermittent antegrade cold blood cardioplegia, during bypass grafting (group B). There were no differences in sex, age, number of grafts, and functional status between the two groups; left ventricular ejection fraction was lower in group A. The overall mortality rate in group A was 0.8% versus 3.6% in group B (p < 0.05). There was no in-hospital mortality among high-risk patients (ejection fraction < or = 0.35) in group A (0/53) versus two deaths in group B (2/28) (p < 0.05). No patient in group A needed circulatory assistance; 4 patients in group B received intraaortic balloon pumping. Only 1 patient in group A required inotropic support versus 20 patients in group B (p < 0.0005), and 5 patients in group A received lidocaine hydrochloride for ventricular arrhythmias versus 18 in group B (p < 0.01). The rates of myocardial infarction and stroke were not different between the two groups. The peak concentration of the myocardial-specific isoenzyme of creatine kinase were higher in group B in absolute value (51 +/- 30 IU/L) than in Group A (38 +/- 38 IU/L) (p < 0.0005) and in percent of total creatine kinase (8.2% +/- 4.1% versus 6.2% +/- 2.9%, respectively).