Value of velocity vector imaging and stress echocardiography in the assessment of systolic function of left ventricular in diabetic rats

Abstract

Objective To investigate whether velocity vector imaging (VVI) combined with stress echocardiography could detect potential myocardial impairment of the left ventricle(LV) in diabetic rats.Methods DM rats ( n = 18,administered by STZ at 65 mg/kg) and control rats( n = 12) were performed with VVI and M-mode echocardiography both at rest and after dipyridamole stress 12 weeks later. Twodimensional echocardiographic cine loops and M-mode images of three consecutive beats were obtained from the short-axis views at the mid-LV level. The means of segmental peak systolic velocity(Vs), circumferential strain(ec) ,radial strain(er), systolic circumferential and radial strain rate (SRc, SRr) and the percent wall thickening (WT% ,derived from M-mode) were obtained. After echocardiograms were performed,the hearts were excised and prepared for HE staining and ultrastructural observations under electron microscopy.Results At rest,only SRc in the DM group was significantly lower than that in the control group( P ＜0.05), the other parameters were statistically comparable between the two groups. After dipyridamole stress,all VVI values in the DM group were significantly lower than those in the control group ( P ＜0.05).However,there was no significant difference in WT% between the two groups either at rest or after dipyridamole stress ( P ＞0.05). Conclusions The VVI parameters combined with dipyridamole stress are more effective in evaluating potential myocardial impairment of the LV walls in diabetic rats. SRc might be more sensitive indices that can be used to detect myocardial impairment at rest. Key words: Echocardiography,stress; Diabetes mellitus; Ventricular function,left; Dipyridamole; Velocity vector imaging