The purpose of this study was to examine the effects of nipradilol on the cardiac function and mRNA expression in Wistar rats with a myocardial infarction (MI) that was created by ligation of the anterior descending coronary. Ten mg x kg(-1) x day(-1) of nipradilol were administrated to the rats in random order, and hemodynamic and Doppler-echocardiographic findings and myocardial mRNA expression were analyzed at 4 weeks after MI. Although left ventricular end-diastolic pressure (LVEDP) and central venous pressure (CVP) were increased in the MI rats, nipradilol significantly reduced the degree of the increase in both parameters. MI also significantly increased the weight of the left and right ventricles, and increased the left ventricular end-diastolic dimension (LVDd), effects that were attenuated by nipradilol. The MI rats showed decreased fractional shortening as systolic dysfunction and decreased E wave deceleration rate as diastolic dysfunction, and nipradilol significantly prevented these. Nipradilol significantly suppressed the increase in the non-infarcted myocardial mRNA expression of atrial natriuretic peptide, brain natriuretic peptide and collagen I and III. In conclusions, nipradilol prevents the cardiac remodeling that is accompanied by systolic and diastolic dysfunction, and inhibits abnormal myocardial gene expression after MI.