This study aim to investigate the myocardium protection effect of cardiomyopeptidin in patients undergoing primary PCI for ST-elevation myocardial infarction through myocardial enhanced MRI.

Investigators will enroll 160 patients with STEMI who were admitted to the Chinese PLA General Hospital between March 2022 and Marchr 2024，the investigators randomly assign eligible patients in a 1:1 ratio to either cardiomyopeptidin intervention group or control group befor primary PCI. The cardiomyopeptidin intervention group patients received intravenous infusion 3 mg/(kg·d) of cardiomyopeptidin during the PCI until 3 days after operation. Primary end point of the study was the area of infarct size measured by cardiac magnetic resonance (CMR). and secondary endpoints include slow flow/no-reflow incidence, corrected TIMI frame count (cTFC), ST-segment fall rate of ECG, cardiac enzymes and troponin, area of myocardial edema, microvascular obstruction, left ventricular ejection fraction, and composite cardiovascular events during the study period: all-cause death, cardiovascular death, unplanned hospitalization for heart failure, and revascularization. All adverse clinical events as well as study end points were monitored and adjudicated by the independent event committee.

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:

• had once treated by ivabradine
• history of myocardial infarction
• mechanical complications
• Unable to perform myocardial MRI
• liver and kidney failure
• malignant tumor
• unconscious
• Patients with other significant abnormal signs, laboratory tests and clinical disease are unsuitable for participation in the study accessed by clinicians.