The aim of this study was to investigate the association between different reperfusion timing and ventricular arrhythmias (VAs) to provide evidence for clinical decision-making for patients with ST-segment elevation myocardial infarction (STEMI). All the participants included in the study were diagnosed with STEMI according to the 4th universal definition of myocardial infarction, with a follow-up of 1, 6, 12 months, respectively. Symptom onset-to-reperfusion timing (SO2RT) and 24h-dynamic electrocardiogram parameters were recorded to compare different SO2RT and VAs during 3 follow-up visits.

It is Class I recommendation that STEMI require emergency revascularization with no delay. However, arrhythmias after acute myocardial infarction (AMI), particularly VAs, also occur in the early post-MI phase, leading to increased mortality. Previous studies have shown benefits of late reperfusion to electrical stability. The aim of this study was to investigate the association between different reperfusion timing and VAs to provide evidence for clinical decision-making for STEMI. In this multicenter, prospective, observational study, STEMI participants from July 2019 to December 2020 confirmed according to the 4th universal definition of myocardial infarction were enrolled, with a follow-up of 1, 6, 12 months, respectively. SO2RT was defined as the time interval between symptom onset and reperfusion timing which referred to the timing when coronary angiography showed Thrombolysis In Myocardial Infarction (TIMI) blood flow level 2~3 immediately after percutaneous coronary intervention (PCI). The primary end point was VAs on 24h-dynamic electrocardiogram. Secondary outcomes included a composite of death from coronary heart disease, fetal of non-fetal ischemic stroke, revascularization, or chest pain requiring readmission.

Inclusion Criteria:

• STEMI patients undergoing coronary angiography and PCI;
• can complete 3 follow-up visits well.

Exclusion Criteria:

• without PCI;
• undergoing thrombolytic therapy;
• mental diseases;
• renal failure;
• stroke sequelae;
• tumor and a history of revascularization.

A prospective cohort study was designed to investigate the effects of different reperfusion timing on VAs in STEMI patients. During the patients' follow-up, 24h-dynamic electrocardiography, echocardiography were required to record the incidence of primary outcome and other parameters. Information on SO2RT, demographic characteristics, hypertension, diabetes and dyslipidemia history, drug use, smoking, drinking, biochemical indexes and coronary lesions were also collected.