Inclusion Criteria:  acute ST-segment elevation myocardial infarction within 12 hours of symptom onset; Age20-80,All genders anterior myocardial infarction The first myocardial infarction The infarct-related artery(IRA) is totally occlusive Blood pressure is higher than 90/60 millimeters of mercury（mmHg） The time from myocardial infarction onset to reach the hospital is less than 12 hs  Exclusion Criteria:  kidney dysfunction (creatinine >2 mg/dl), History of previous liver disease, Cardiogenic shock, History of myocardial infarction (MI) History of coronary artery bypass grafting History of allergic response to drugs Severe hypovolemia