BACKGROUND: Little is known about the prognosis of patients with acute myocardial infarction (MI) and preserved left ventricular ejection fraction (LVEF), a condition that is becoming increasingly common. This study sought to identify independent predictors of adverse outcomes in patients with acute MI and preserved LVEF. METHODS: We studied the prognosis of 555 patients with acute MI (mean age 62 years, 287 men) and preserved LVEF (>40%). Primary endpoint was a composite of cardiovascular (CV) death and rehospitalization for heart failure (HF). RESULTS: During follow-up of a median 24 months (range 0-50 months), there were 34 cardiac events (cardiac death in 28 and rehospitalization for HF in six patients). Significant univariate predictors of CV death and rehospitalization for HF were age, Killip class greater than I, revascularization, estimated glomerular filtration rate, log N-terminal probrain natriuretic peptide (NT-proBNP), LVEF, left atrial volume index, and the ratio of early diastolic mitral inflow velocity to early diastolic mitral annular velocity (E/E') greater than 15. In multivariate Cox analysis, age (hazard ratio 1.05, 95% confidence interval: 1.01-1.09, P=0.02) and log NT-proBNP (hazard ratio 2.08, 95% confidence interval: 1.61-2.70, P<0.001) independently predicted CV death and rehospitalization for HF. Receiver operating curve analysis indicated that NT-proBNP showed significantly higher areas under the receiver operating characteristic curve value than other significant predictors including left atrial volume index and estimated glomerular filtration rate for prediction of adverse outcomes. CONCLUSION: NT-proBNP showed a strong predictive power for adverse outcomes beyond traditional risk factors and echocardiographic indices of LV systolic and diastolic function in patients with acute MI and preserved LVEF.