There are always poor outcomes in patients with acute myocardial infarction(AMI) combined with elevated BNP/NT-proBNP level. An elevated BNP/NT-proBNP level highly indicates acute heart failure(AHF).Levosimendan is recommended in many clinical trials of heart failure and Chinese heart failure guidelines. As a result, the investigators form a hypothesis that when patients with AMI combined with elevated BNP/NT-proBNP level are in conditions before AHF, to use levosimendan may reduces the risk of heart failure and improve the outcome.