Quantitative assessment of left ventricular systolic synchrony before and after stress in chronic ischemic model by real-time three-dimensional echocardiography / 中华超声影像学杂志

ABSTRACT

Objective To assess the left ventricular systolic asynchronicity in chronic ischemic model with real-time three-dimensional echocardiography (RT-3DE), and to explore the affection of low-dose dobutamine to it. Methods A chronic ischemic model was induced by placing an Ameroid constrictor in the left circumflex(LCX) in swines,then full volume RT-3DE was performed by Philips iE33 with X3-1 probe combining rest and stress(dobutamine stress echocardiography, DSE) every week after LCX constriction.Ten normal pigs before operation served as controls (group A). Examination of all the models post operation were grouped into group B (mild stenosis, LCX stenosis＜50% ), group C (moderate stenosis, LCX stenosis 50%～75%) and group D (severe stenosis, LCX stenosis≥75%) according to the results of coronary angiography. Images were copied to QLAB 5.2 postprocess workstation,and 3DQA software was used to analyze the full volume data sets. The time to the point with minimal systolic volume (Tmsv) in each segment was taken to derive the following indexes of systolic synchrony the maximum difference of Tmsv (Tmsv-dif) and standard deviation(Tmsv-SD) among various segments and standard index (Tmsv-dif% and Tmsv-SD%), to evaluate left ventricular dyssynchrony. Tmsv3-6 represented the maximum difference of Tmsv between lateral segment and posterior septum (Tmsv3-5 between lateral segment and inferior) in basal level. Results Tmsvl2-Dif%, Tmsv6-Dif%, Tmsv3-6% and Tmsv3-5% under stress condition in group C and D were significantly higher than those at rest;all the data in group D were significantly higher than in group A and B, and in group C higher than group A ( P ＜0.05,0.01 ). Compared with group A,Tmsv6-Dif,Tmsv3-6 and Tmsv3-5 in group B were significantly increased under stress condition,and so did their standardize data under both rest and stress conditions ( P ＜ 0.05, 0. 01 ). Conclusions RT-3DEcombined with DSE could display sensitively the left ventricular asynchrony caused by chronic ischemia,and that will be more significant in lateral wall in LCX stenosis than in normal segments.