Evaluation of the Effect of Ischemic Postconditioning on Ischemia-reperfused Canine Heart by Quantitative Tissue Velocity Imaging

Objective To evaluate the effect of ischemic-postconditioning on ischemia-reperfused canine myocardial function by quantitative tissue velocity imaging(QTVI).Methods Twenty-one dogs were randomly divided into three groups,with 7 dogs in each group.In the control group(con group),the left anterior descending artery(LAD) was reversibly occluded for 60 minutes,followed by 3-hour reperfusion.In the ischemic-preconditioning group(Pre-C group),four cycles of 5-minute reperfusion and 5-minute reocclusion were performed before the prolonged LAD occlusion.In the ischemic-postconditioning group(Post-C group),three cycles of 30-second reperfusion and 30-second reocclusion were performed 1 hour after LAD occlusion.The systolic peak velocity(Vs) and systolic peak displacement(Ds) were measured on anterior wall and inferior wall,anterior septum and post wall,post septum and lateral wall by QTVI.The left ventricular ejection fraction(LVEF) was measured using Simpson's method and the fractional shortening(FS) was measured by anatomical m-mode echocardiography.Results Vs,Ds,LVEF and FS decreased significantly at the end of ischemia in all groups.Compared with the control group,Vs,Ds,LVEF and FS increased 3 hours after reperfusion in Post-C group and Pre-C group(P0.05),and Vs and Ds were correlated with LVEF and FS(r were 0.844、0.793、0.800、0.760,all P0.05).Conclusion QTVI can evaluate systolic function exactly in myocardial ischemia-reperfused dogs,and Ischemic-postconditioning may have protective effects on ischemia-reperfused canine heart.