兔室壁瘤形成后左心室舒张及收缩功能的变化

Changes of left ventricular diastolic and systolic function in rabbits with ventricular aneurysm

目的应用二尖瓣血流脉冲多普勒(PWD)频谱及二维超声斑点追踪显像(STI)技术观察兔心肌梗死室壁瘤形成后左心室舒张和收缩功能的变化特点。方法以28只健康新西兰大白兔制作心肌梗死模型,饲养4周,23只兔成模并存活。以建模前超声检查作为对照组,术后4周复查超声并行病理学检查,根据有无室壁瘤形成分为心肌梗死组(n=11)和室壁瘤组(n=12)。测量左心室二维超声指标后,应用PWD分别测量各组二尖瓣的舒张早期血流速度(E)、舒张晚期血流速度(A);应用STI技术分别测量各组左心室短轴瓣环水平、心尖水平各节段的旋转角度、短轴瓣环水平圆周应变率(SrC)和径向应变率(SrR)的收缩期峰值应变率(SrC-S,SrR-S)、舒张早期峰值应变率(SrC-E,SrR-E)、舒张晚期峰值应变率(SrC-A,SrR-A),计算左心室整体扭转角度及舒张早期与舒张晚期峰值应变率之比(SrCe/SrCa,SrRe/SrRa)。结果与对照组比较,心肌梗死组和室壁瘤组左心室整体扭转角度及SrCe/SrCa、SrRe/SrRa均减小,以室壁瘤组更显著(P均<0.05);各组间E/A差异无统计学意义(P均>0.05)。结论兔心肌梗死室壁瘤形成后,E/A呈假性正常化,而短轴瓣环水平圆周和径向应变率、左心室整体扭转角度显著减小,左心室局部和整体舒张功能及收缩功能进一步恶化。

Objective To evaluate the characteristics of left ventricular （LV） diastolic and systolic function in rabbits with left ventricular aneurysm （LVA） with transmittal pulsed wave Doppler （PWD） and speckle tracking imaging （STI）. Methods Left anterior descending coronary artery and left circumflex artery were ligated to induce myocardial infarction （MI） of 28 normal rabbits. There were 23 survivors after 4 weeks. With pre-modeling ultrasonography as control group echocardiography and pathology was performed after operation. According to whether LVA formed or not, 23 rabbits were divided into MI group （n=11） and LVA group （n=12）. The two-dimensional ultrasonic indexes of LV were measured, then the E peak of blood flow peak velocity in the left ventricular early diastole stage, and the A peak in the left ventricular late diastole stage was measured by PWD. STI was performed to measure rotations at the levels of mitral annulus and apex in LV short-axis view, circumferential strain rate （SrC） and radial strain rate （SrR） indexes including peak systolic strain rate （SrC-S, SrR-S）, peak early diastolic strain rate （SrC-E, SrR-E）, and peak late diastolic strain rate （SrC-A, SrR-A） at the levels of mitral annulus in LV short-axis view. LV twist the ratio of peak early diastolic strain rate and peak late di- astolic strain rate （SrCe/SrCa, SrRe/SrRa） was calculated. Results Compared with pre-operation, LV twist, SrCe/SrCa and SrRe/SrRa were lower in MI group and LVA group, especially in LVA group （all P〈0.05）. However, E/A showed no significant difference among groups （all P〉0.05）. Conclusion With LVA formation in rabbits, E/A shows pseudo normalization, while SrC, SrRand LV twist reduce significantly, indicating further deteriorated left ventricular diastolic and systolic function.