In this study we evaluated the outcome of coronary artery bypass grafting (CABG) in patients with coronary artery disease and left ventricular dysfunction. The aim of the study was to identify the risk factors for operative and medium-term mortality. We evaluated 117 consecutive patients (98 men, 19 women, aged 42 to 84 years, mean 65 +/- 9) with ejection fraction (EF) < 40%, operated on from January 1994 to December 1995. Patients who had previously undergone CABG, or who had other procedures associated with CABG, were excluded. Preoperatively, mean EF was 32 +/- 5%; 65 patients (56%) had angina and 62 (53%) had congestive heart failure in NYHA functional class III and IV. Hospital mortality rate was 5% (i.e. 6 deaths). At multivariate analysis significant risk factors were: NYHA functional class IV and moderate/ severe mitral regurgitation. All patients were evaluated at a mean follow-up time of 13 +/- 8 months (range 3 to 30); 9 deaths occurred, 7 due to cardiac causes. Actuarial survival rate at 24 months was 85 +/- 4%; freedom from death due to cardiac causes was 87 +/- 4%. Significant risk factors for medium-term mortality at multivariate analysis were age, moderate/severe mitral regurgitation and marked impairment of regional myocardial contractile function, evaluated by the wall motion score index (> or = 2.25). At follow-up the majority of patients showed improved clinical conditions: mean EF was 40 +/- 8%; 8 patients (8%) had angina and 12 (12%) were in NYHA functional class III and IV. Myocardial revascularization in patients with coronary artery disease and left ventricular dysfunction is characterized by low operative risk and good survival rate at 2 years, with improvement of both angina and congestive heart failure. The best results were obtained in those patients who preoperatively showed the best regional contractile function, even though the global EF was poor, and in those with signs of reversible left ventricular dysfunction, such as angina or documented myocardial viability.