Background: Previous studies of the prognosis of myocardial infarction (MI) have focused primarily on patients with left ventricular (LV) systolic dysfunction. Little is known about the prognosis of patients with MI and preserved EF, which is increasing. Since the ratio of mitral inflow (E) and annular velocity (E���) to stroke volume (E/E���/SV) has been reported as an index of diastolic elastance (Ed), we hypothesized that Ed has prognostic implication in patients with MI and preserved EF. Method : Between May 2005 and June 2007, a total of 421 patients with acute MI were prospectively enrolled in Infarction Prognosis Study (IPS) registry. Among them, 358 patients who had comprehensive echocardiographic study, 44 patients with significant valvular heart disease or coexisted cardiomyopathy and 59 patients with decreased EF (<40%) were excluded. This left a total of 255 patients, who constituted the study population. The primary end-point was cardiovascular mortality or readmission due to congestive heart failure. Results : Median follow-up duration was 18 months. Of 255 patients, Primary end-point (cardiovascular mortality or readmission due to congestive heart failure) were occurred in 16 (6.3%) patients. In univariate and multivariate Cox regression analysis, Ed was a powerful predictor, and remained independent predictor of cardiovascular mortality or readmission due to congestive heart failure in patients with acute MI and preserved EF (p=0.006, HR; 1.87, 95% CI; 1.19-2.94). Cut-off value of Ed for primary end-point determined by Kaplan-Meier method (p<0.001 by log-rank test) and ROC curve (AUC 0.90, sensitivity 100%, specificity 77%) was 0.26. In multivariate linear regression model, Ed was independently associated with gender (female, p=0.001), DM (p=0.015), NT-proBNP (log transformation, p=0.002), and RV systolic pressure (p=0.001) as well. Conclusion : Non-invasively determined ventricular diastolic elastance (Ed) is a novel and powerful independent predictor of cardiovascular mortality and development of congestive heart failure in patients with acute MI and preserved EF.