Giving preoperative loading dose of 60mg of trimetazidine can safely and effectively reduce the PCI-related myocardial damage for the patients undergoing selective PCI. but the effect of Trimetazidine during the primary PCI on cardiac function in patients with ST-elevation myocardial infarction is not sure. this study aim to study the effect of Trimetazidine during the primary PCI on cardiac function in patients with ST-elevation myocardial infarction.

Investigators will enroll 240 patients with STEMI who were admitted to the Chinese PLA General Hospital between Januay 2017 and August 2017. STEMI was defined as typical chest pain lasting 30 min within the previous 12 h, a clear ST-segment elevation of N0.1 mV in ≥2 contiguous electrocardiographic leads, and elevated blood levels of troponin T. We randomly assign eligible patients in a 1:1 ratio to either 60mg of trimetazidine or oral placebo befor PCI. Trimetazidine group will accept 20mg of trimetazidine for 12 months after PCI and active Comparator will be given placebo for 12 months after PCI.

Primary end point of the study was the area of viable myocardium coming from MR delayed enhancement scan and main cardiovascular events concluding recurrent myocardial infarction, cardiac death, recurrent angina, acute heart failure. Secondary end point of the study was the change of LVEF. All adverse clinical events as well as study end points were monitored and adjudicated by the independent event committee. Each patient was contacted in every week after administration of the contrast, investigated main cardiovascular events (myocardial infarction,acute heart failure and death), and record any adverse events.

Inclusion Criteria:

• STEMI patients: typical chest pain lasting 30 min within the previous 12 h, a clear ST-segment elevation of N0.1 mV in ≥2 contiguous electrocardiographic leads, and elevated blood levels of troponin T
• patients were scheduled to undergo diagnostic cardiac angiography or percutaneous coronary interventions

Exclusion Criteria:

• The combined use of trimetazidine contraindications;
• had cardiogenic shock,
• had a history of myocardial infarction, stent thrombosis, or renal insufficiency;
• had previously undergone coronary artery bypass surgery.