Clinical Efficacy and sAfety of Intravenous Infusion of Nicorandil During Primary Percutaneous Coronary Intervention

Inclusion Criteria: * 18-80 years; * acute ST-segment elevation myocardial infarction within 12 hours of symptom onset; Exclusion Criteria: * systolic blood pressure\<100mmHg; * cardiac shock; * aortic dissection; * history of myocardial infarction or percutaneous coronary intervention or coronary artery bypass grafting (\<6 month); * history of the treatment of nicorandil (\<6 month); * history of intravenous nitrates before percutaneous coronary intervention; * contraindicated or intolerable to nicorandil; * pregnant or lactation period; * patients with an estimated survival time of less than 1 year.