定量组织速度成像评价氯沙坦对大鼠急性心肌梗死后左室重构的左室功能影响

Evaluation of the effects of losartan on left ventricular remodeling and function after acute myocardial infarction in rats by quantitative tissue velocity imaging.

目的 探讨定量组织速度成像结合常规超声心动图评价大鼠心梗后左室重构的应用价值及氯沙坦对大鼠急性心梗后左室重构的左室功能影响。方法 将冠脉左支起始部结扎后存活的SD大鼠随机分为氯沙坦组 (L组 ,16只 )和空白对照组 (C组 ,12只 ) ;另 10只假手术大鼠作为正常对照 (S组 )。治疗 4周后分别进行超声心动图检查。结果 与S组相比 ,C组的左室舒张末期内径、舒张末期容积、左室相对重量极显著增加 (P <0 .0 1) ;射血分数、球形指数、梗死区变薄指数等指标极显著降低 (P <0 .0 1) ;E/A比值明显增大 ,E峰减速时间明显延长 (P <0 .0 5 )。L组与C组相比以上各指标均有明显地改善(P <0 .0 5 )。与C组相比 ,L组心脏长轴方向上二尖瓣环处速度指标有显著地改善 (P <0 .0 5 )。二尖瓣环平均收缩期峰值速度与左室射血分数、球形指数等呈线性相关 (r1=0 .84 ,r2 =0 .70 ,P <0 .0 0 1)。超声所计算的左室相对重量及梗死面积范围与实体标本所测的相关性很好 (r1=0 .79,r2 =0 .89,P <0 .0 0 1)。结论 定量组织速度成像结合常规超声心动图能较全面、精确、定量评价大鼠心梗后左室重构的左室功能及氯沙坦抑制左室重构。

Objective We attempted to assess the effects of losartan on left ventricular remodeling after acute myocardial infarction in rats by quantitative tissue velocity imaging and general echocardiography.Methods After ligation of the main branch of left coronary artery, 28 surviving female Sprague-Dawley rats were randomly assigned to two groups: Losartan group(L group,n=16), acute myocardial infarction control group (C group,n=12). A sham-operated group (S group,n=10) was also randomly selected. Four weeks after treatment, echocardiography scan was performed in each group.Results When compared with S group, the left ventricular end-diastolic diameter, left ventricular end-diastolic volume and left ventricular relative mass in C group were all significantly increased (P< 0.01). The parameters in C group including ejection fraction, sphericity index, infarction regional thinning index were all significantly decreased (P< 0.01). The parameters of diastolic function in C group including E/A ratio and E peak descending velocity time were all significantly increased (P< 0.05). When compared with C group, the parameters all above in L group were all significantly improved (P< 0.05). When compared with C group, the parameters of velocity at mitral annulus in L group was significantly increased (P< 0.05). The mean peak systolic velocity at mitral annulus correlated positively to ejection fraction and sphericity index (r 1= 0.84,r 2= 0.70, P< 0.001). The left ventricular relative mass and myocardial infarction size from echocardiography correlated well with the result from pathologic specimen (r 1= 0.79,r 2= 0.89,P< 0.001).Conclusion Losartan has beneficial effects on preventing left ventricular remodeling and improving left ventricular function. By quantitative tissue velocity imaging and general echocardiography, we could assess the effects and left ventricular function of remodeling after acute myocardial infarction in rats comprehensively, accurately, quantitatively.