Objective To observe effect of different doses of atorvastatin on changes of left ventricular function and plasma brain natriuretic peptide(BNP) in patients with acute myocardial infarction(AMI) on percutaneous coronary angioplasty.Methods Left ventricular end diastolic diameter(LVEDd),left ventricular ejection fraction(LVEF) and left ventricular fractional shortening(LVFS) of patients with AMI and 20 healthy cases were examined by echocardiography,and their plasma level of brain natriuretic peptide(BNP) were measured by enzyme-linked immunosorbent assay(ELISA).The AMI group were randomly divided into atorvastatin 20mg group(n=25) and 40mg group(n=25).The intexes were retested after PCI and 1 month.Results There were significant differences in the level of LVEDd,LVEF and LVFS between atorvastatin 20mg group and in atorvastatin 40mg group after 1-month treatment(P0.05).Two treatment groups had significant differences of these intexes before treatment and after treatment(P0.05).The plasma BNP levels decreased significantly after 1 month treatment in atorvastatin 20mg and in atorvastatin 40mg group(P0.01).There was a significant difference between the two treatment groups(P0.05).Conclusion The AMI patients treated with early high dose of atorvastatin can improve cardiac function and reduce plasma BNP levels,reduce the incidence of heart failure,thereby improving the long-term prognosis of patients and reduce mortality.