ABSTRACT
Pressure overload diseases such as valvular stenosis and systemic hypertension morphologically manifest in patients as cardiac concentric hypertrophy. Preventing cardiac remodeling due to increased pressure overload is important to reduce the morbidity and mortality. A recent clinical study has shown that carvedilol has beneficial effects on the survival rate of patients with heart failure. This may be due to the actions of carvedilol such as beta-adrenoceptor blockade and the alpha1-adrenergic receptor blockade effects. Therefore, we investigated whether carvedilol can reverse preexisting cardiac hypertrophy and we compared the effects of racemic carvedilol and the carvedilol enantiomers. Cardiac hypertrophy was induced in rats by suprarenal transverse abdominal aortic constriction (AC). Fifteen weeks after AC surgery, concentric hypertrophy was identified in the AC group by performing echocardiography. Low dose S- and SR-carvedilol (2 mg/kg/day), which were orally administered for three weeks, caused significant regression of the cardiac hypertrophy, and this most significantly occurred in the rats that received S-carvedilol. However, R-carvedilol did not reduce cardiac hypertrophy. Regression of cardiac hypertrophy by carvedilol was confirmed on the echocardiograms and electrocardiograms. These results suggest that carvedilol could reverse the development of leftventricular concentric hypertrophy that is induced by pressure overload. S-carvedilol is proposed to be superior to SR-and R-carvedilol as a beneficial treatment for cardiac hypertrophy.