We evaluated the prognostic effect of baseline left ventricular function and the determinants of its recovery after acute myocardial infarction (AMI) treated by primary angioplasty. Left ventriculography was performed during the index procedure in 1,620 of 2,082 patients (78%) who underwent primary angioplasty for AMI in the CADILLAC trial. One-year survival rate was significantly lower in patients whose baseline left ventricular ejection fraction (LVEF) was <40% than in those whose LVEF was > or =40% (89.0% vs 97.2%, respectively, p <0.0001). The effect of baseline left ventricular dysfunction on mortality was confined to the first 3 months after AMI; thereafter, survival was independent of baseline LVEF. By multivariate analysis, baseline LVEF (hazard ratio 0.93, 95% confidence interval 0.90 to 0.97, p <0.001) and infarct zone regional wall motion (hazard ratio 2.67, 95% confidence interval 1.08 to 6.63, p = 0.03) were independent predictors of 1-year mortality. Seven-month convalescent LVEF was also directly related to baseline LVEF and inversely correlated with previous AMI, multivessel coronary disease, preprocedural Thrombolysis In Myocardial Infarction grade 0 to 2 flow, larger infarct artery diameter, and infarct artery restenosis at follow-up. In conclusion, baseline left ventricular function measured during the index procedure is a strong independent predictor of early and late survival after primary angioplasty. Simple clinical and angiographic features readily available at the time of primary angioplasty also predict convalescent LVEF and are thus of prognostic utility.