Trimetazidine is a agent promoting glucose utilization by limiting fatty-acid oxidation.Trimetazidine could improve cardiac function in patients with ischemic heart disease. We aimed to explore effect of Trimetazidine on final myocardial fibrosis for patients with ST-elevation myocardial infarction (STEMI) in real world clinical practice. In this observational study, we investigated the effect of long-term treatment with trimetazidine on the final extent of myocardial fibrosis measured by cardiac magnetic resonance 6 months after infarction in real world clinical practice.