Ventricular remodeling after acute myocardial infarction can have a strong influence on the function of the ventricle and the prognosis of the patients. The aim of this study was to investigate the effect of carvedilol on the ventricular remodeling with respect to infarct size after myocardial infarction in rats.

Rats were randomly assigned to a carvedilol-treated (n=24), or untreated group (n=31) after left coronary artery ligation. Passive pressure-volume relationships of the left ventricle were determined to evaluate ventricular volume and the slopes of this relationship were analyzed to characterize ventricular chamber stiffness at about 6 weeks.

In the case of infarct size in the range 10-34%, ventricular volume indeces indices of the carvedilol-treated rats (n=5) tended to be decreased to a greater extent than those of the untreated rats (n=5) as shown in the pressure-volume curve. In the case of infarct size in the range 35-49%, there was no significant difference in ventricular volume indices between the carvedilol-treated (n=6) and the untreated (n=6) rats. In the case of infarct size greater than 50%, the pressure-volume curve stiffness constant k0 (2.5-30 mmHg) of the carvedilol-treated rats (n=3, 2.13±0.35) was significantly greater than that of the untreated rats (n=5, 1.55±0.16) and the ventricular volumes of left ventricular filling pressure 10-30 mmHg were lower in the carvedilol-treated rats than in the untreated rats.

A leftward shift of the pressure-volume curves was noted in experimentally induced myocardial infarction-induced rats, that treated by carvedilol.