Background: The microvascular function was known to be an useful predictor of left ventricular functional changes and clinical outcomes in ST-segment elevation myocardial infarction (STEMI). We evaluated the usefulness of integrated approach by using coronary flow velocity reserve (CFR) and diastolic deceleration time (DDT) in the prediction of long-term major adverse cardiac events in STEMI. Methods and Results: Using an intracoronary Doppler wire, CFR and DDT were evaluated in 193 patients with first STEMI received percutaneous coronary intervention (PCI) within 24 hours after onset of symptoms. Major adverse cardiac events were the composite of cardiac death, recurrent myocardial infarction, congestive heart failure and stroke during an average follow-up period of 46 짹 36 months. Follow-up echocardiography was performed at 12 짹 11 months. CFR and DDT had significant correlations with left ventricular regional wall motion score index at follow-up echocardiography (r = -0.396, p<0.001; r = 0.446, p<0.001, respectively). Using receiver-operating characteristics analysis, CFR���1.5 (sensitivity: 65%, specificity: 61%, AUC: 0.654), DDT���567 ms (sensitivity: 71%, specificity: 65%, AUC: 0.717) were the best cutoff values in prediction of occurring the adverse cardiac events. In patients with CFR���1.5, DDT���567 ms, cardiac events were occurred in 16 patients (31.4%) of 51 patients, whereas cardiac events were only occurred in 5 patients (6.1%) of 82 patients with CFR>1.5 and DDT >567 ms (p=0.001)(Table). Integrated microvascular integrity index (p=0.003), ejection fraction at admission (p=0.018) and DDT (p=0.016) were independent predictors of long-term adverse cardiac events. Conclusions: Integrated approach by using CFR and DDT was useful in the prediction of long-term adverse cardiac events.