应变及应变率成像评价心肌梗死后心力衰竭大鼠左室收缩功能

Evaluation of myocardial systolic function of heart failure induced by myocardial infarction in rats with strain and strain rate imagine

目的:应用应变及应变率成像技术定量评价心肌梗死后心力衰竭大鼠心肌局部收缩功能的改变。方法:选用2月龄成年雄性SD大鼠70只,随机分为4组,其中手术4周组(n=25)及手术8周组(n=25):麻醉后行开胸术,打开心包,结扎左冠状动脉前降支;假手术组(n=10):同样开胸,打开心包,但不结扎;正常组(n=10):不予任何处理。术后每日观察大鼠的精神状态等一般情况的变化。术后4周末及术后8周末均行超声心动图检查,应用应变及应变率成像技术定量评价左室局部收缩功能的改变;测量结果行重复性及差异性分析。结果:术后存活大鼠在术后第10～14天均出现明显心力衰竭体征;与正常组及假手术组相比,手术4周组左室短轴缩短率(FS)及射血分数(EF)均下降(P<0.05);手术8周组左室内径指数(LV指数)增大,左室后壁指数(LVPW指数)及室间隔指数(IVS指数)均减小(P<0.05),FS及EF均下降(P<0.01),其中手术8周组FS及EF值较手术4周组明显减低(P<0.05)。与正常组及假手术组相比,除下壁中间段及基底段外,手术组各节段收缩期峰值应变(Ssys)、收缩期峰值应变率(SRsys)、收缩末期应变的绝对值均明显下降(P<0.05),而收缩后应变指数(PSI)升高(P<0.05)。结论:超声应变及应变率成像技术可定量检测心力衰竭大鼠左室局部心肌收缩功能改变,其重复性较好。

Objective To quantitatively detect variation in regional myocardial systolic function in heart failure rat model induced by myocardial infarction by strain and strain rate imaging.Methods Seventy 2-month-old adult male SD rats were randomly assigned to 4 groups：a 4-week and a 8-week group after the operation （each n=25） had thoracotomy,the pericardium opened and the anterior descending branch of left coronary artery ligated;a sham operation group （n=10） had thoracotomy and the arcula cordis opened,but did not ligate the artery;a control group （n=10） had no treatment.The changes of general state of health of the rats were observed and recorded every day.To assess the change of heart function,echocardiography was used at the end of the 4th week and 8th week after the surgery.To evaluate the change of heart function in heart failure rats,we quantitatively analyzed the regional myocardial systolic function in all rats by strain and strain rate imaging and myocardium to detect the level of MMP-9 at the end of the 4th week and 8th week.The repeatability and discrepancies of the results were all analyzed.Results Obviously objective signs of heart failure manifested themselves in the survived mice 10 to 14 days after the surgery.Compared with the control group and the sham operation group,the fraction shortening （FS） and ejection fraction （EF） of the 4-week group after the operation were lower （P0.05）,the left ventricle index （LV index） of the 8-week group after the operation was higher,left ventricle posterior wall index （LVPW index）,interventricular septum index （IVS index）,FS,and EF of the 8-week group after the operation were lower （P0.05）,EF and FS of the 8-week group after the operation were lower than those of the 4-week group.Except the mid-inferior wall and base-inferior wall,the systolic peak strain,systolic peak strain rate,the strain of end-systole in all segments of the operation group were lower than those of the other 2 groups（P0.05）.The post-systolic strain index of the operation group was higher than that of the other 2 groups （P0.05）.Conclusion Strain and strain rate imaging of echocardiography can quantitatively evaluate the changing of regional myocardial systolic function in the heart failure rat model induced by myocardial infarction,with good repeatability.