This study aim to investigate the predictive value of CMR parameters: infarct size (IS), intramyocardial hemorrhage, microvascular obstruction, area at risk and CMR derived strain parameters with the Major Adverse Cardiovascular Events (MACEs) and myocardial remodeling afterinfarction.

Investigators will enroll 500 patients with STEMI after PCI who were admitted to the Chinese PLA General Hospital and other eight hospitals across China: Wuhan Asia Heart Hospital; the First People's Hospital of Yunlin; Chaoyang Hospital, Capital Medical University; Hainan Hospital of PLA General Hospital; the Second Affiliated Hospital of Nanchang University; the Second Hospital of Hebei Medical University; Guizhou Provincial People's Hospital; Affiliated Hospital of Zunyi Medical College between January 2014 and December 2019. CMR was performed at 7 days and 6 months after primary PCI to assess the final infarction size(IS), microvascular obstruction (MVO), intramyocardial hemorrhage(IMH), area at risk (AAR) and related strain parameters. All patients will be followed up by 5 years after adimission. Cardiovascular events concluded stroke, repeat revascularization, rehospitalization for acute heart failure, nonfatal myocardial infarction, and all cause death. All adverse clinical events as well as study end points were monitored and adjudicated by the independent event committee.

Inclusion Criteria:

1. Age 18-80 years.
2. clinically diagnosed ST-segment elevation myocardial infarction.
3. Intended to undergo emergency PCI.
4. Voluntary enrollment and signed informed consent form.

Exclusion Criteria:

1. undergoing revascularization (PCI or coronary artery bypass grafting (CABG)) within 6 months;
2. Pregnant and breastfeeding women;
3. Contraindications of CMR: implanted cardiac defibrillator (ICD), claustrophobia, allergy to gadolinium
4. Liver or kidney failure;
5. Malignant tumor;
6. Unconscious at present;
7. systolic blood pressure (SBP) less than 80 mmHg;
8. Patients with bundle branch or fascicular block, insufficient ECG data.
9. Patients with other significant abnormal signs, laboratory tests and clinical disease are unsuitable for participation in the study accessed by clinicians.

Investigators will enroll 500 patients with STEMI after PCI who were admitted to the Chinese PLA General Hospital and other eight hospitals across China between January 2016 and January 2019. CMR was performed at 7 days and 6 months after primary PCI to assess the final infarction size, microvascular obstruction (MVO), area at risk (AAR) and related strain parameters. All patients will be followed up by 5 years after addimission index.