Inclusion Criteria:  Acute myocardial infarction undergoing primary percutaneous coronary intervention; Aged 18 years or over and under 80 years; 35% < LVEF < 50% and LV < 65mm; With informed consents  Exclusion Criteria:  Severe symptomatic congestive heart failure (KILLIP cardiac function class III-IV); Malignant arrhythmias (ventricular fibrillation, ventricular tachycardia, frequent multiple source ventricular premature); Uncontrolled hypertension (systolic blood pressure greater than 160mmhg, diastolic blood pressure greater than 100mmhg); Life-threatening diseases with limited life expectancy <6 months; Inability or difficulty to exercise; Participation in other clinical trials