Effects of Valsartan on Left Ventricular Remodeling after Acute Myocardial Infarction in Rats

Objective To study the effects of valsartan on left ventricular remodeling after acute myocardial infartion in rats. Methods Twenty-four hours after the operations of ligation on the coronary arteries , the surviving SD rats were randomly divided into 3 groups; AMI group, low-dose valsartan treatment group(10mg ·kg-1·d-1)and high-dose valsartan treatment group(30 mg · kg -1· d-1). The sham- operated group was also estabished. After four weeks of treatment, the following items were measured; (1) the function of left ventricle; ( 2 ) body weight ( BW) ,, left ventricaular mass ( LVM ) and LVMI ( left ventricular mass index) ;(3)the infarct size of the heart; (4) The collagen volume fraction ( CVF) of the noninfarct zone in left ventricle (LVNIZ). Results There was no significant difference in the infarct size of the heart among the AMI groups(P 0.05). Compared with the sham-operated group, LVEDP,LVM,LVMI,,CVF of AMI group increased significantly (P all 0.01) while LVSP and ±dp/ dtmax decreased significantly (P 0.01) . High- dose valsartan decreased LVEDP and increased ±dp/ dtmax of AMI group( P 0. 01) while low-dose valsartan had no significant effect on the function of left ventricle in AMI group. Both high and low dose valsartan decreased LVM.LVMI.CVF of AMI group significantly (P all 0.01) and the high dose valsartan had a more significant effect than the low dose( P 0. 01) . Conclusion Valsartan can limit myocardial hyper trophy, attenuate the development of myocardial interstitial fibrosis in the noninfarcted left ventricle and so improve left ventricular remodeling after acute myocardial infartion in rats.