Effect of Carvedilol on Strain and Strain Rate in Rabbits with Chronic Heart Failure

OBJECTIVE To investigate the effect of carvedilol on myocardial strain and strain rate and to evaluate its roles and significance on regional myocardial function in rabbits with chronic heart failure. METHODS Thirty Japanese rabbits were randomly devided into 3 groups: control (CTL group,n=6), chronic heart failure group (CHF group,n=12) and carvedilol-intervened group (CVD group，n=12). Rabbits in CHF and CVD group were intravenously injected at auri-edge with adriamycin hydrochloride twice a week for 8 weeks with a concentration of 1 mg·kg-1, the CTL group was injected with equal saline at the same timepoint. Thereafter, rabbits in CTL and CHF group were administrated ig with 5 mg·kg-1·d-1 saline , and CVD group with equal volume of carvedilol-saline, daily for 8 weeks. The serum B-type natriuretic peptide (BNP) level in 3 group of rabbits were detected on week 12 and week 20, respectively.Meanwhile, the left ventricular end-diastolic dimension (LVEDD), left ventricular ejection fraction (LVEF) and fractional shortening (FS) were measured by echocardiography, the peak systolic and peak diastolic strain (PSS and PDS), the systolic and early diastolic strain rate (SRs and SRe) derived from the basal segment of inter-ventricular septum (BS-IVS) and left ventricular lateral wall (LVLW) were assessed by strain rate imaging. RESULTS In comparison with CTL group, the serum BNP level and LVEDD in CHF and CVD group of rabbits were significantly increased, while the LVEF, FS, SRs,SRe, PSS and PDS of BS-IVS and LVLW were significantly decreased on week 12. In CVD group, the serum BNP level, the LVEDD on week 20 were significantly decreased in comparison with those on week 12, while the LVEF, FS , SRs、SRe、PSS and PDS were significantly increased.While in CTL and CHF groups, there was no significant change in above parameters. CONCLUSION The systolic and peak diastolic strain and strain rate of regional myocardium were decreased in chronic heart failure.Carvedilol can improve the global systolic function and cardiac remodeling in chronic heart failure rabbits and can also increase the systolic and peak diastolic strain and strain rate thus improve regional myocardial function.