Objective:To investigate the effects of emergency percutaneous coronary intervention(PCI)treatment on left ventricular functions of patients with acute ST-segment elevation myocardial infarction.Methods: All cases enrolled in were 65 patients admitted for the first acute ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention from September 2007 to October 2009,which included 35 cases in emergency PCI group(group P) and 30 cases in selective PCI group(control group,group C).After PCI,all patients were examined by echocardiography in 7 days and 6 months respectively.Left ventricular ejection fraction and mitral flow spectrum were measured to evaluate left ventricular systolic and diastolic functions.Overall cardiac functions were evaluated by 6-minute walking test in 6 months after PCI.Results: The left ventricular systolic and diastolic functions in group P were superior to those of group C,and the cardiac functions of group P were also significantly superior to that of group C proved by the results of 6-minute walking test.Conclusions: Emergency PCI may apparently improve left ventricular systolic and diastolic functions of patients with acute ST-segment elevation myocardial infarction,and to raise life qualities as well.