Objective:Using two-dimensional speckle tracking imaging(2D-STI) to analysis layer-specific strain of rabbits' left ventricular(LV) in the early stage of acute myocardial ischemia(AMI), which is to assess global and regional systolic function of LV. Methods:AMI model of forty white rabbits was established through ligating the left ventricular branch of coronary artery. Two-dimensional images were recorded and stored in apical four-chamber,long-axis,two-chamber and the short-axis view at the level of mitral valve,papillary muscle and apex. The highest value of longitudinal strain(LS),circumferential strain(CS),global longitudinal strain (GLS) and circumferential strain(GCS),using EchoPAC was respectively assessed from endocardium,mid-myocardium and epicardium of 18 sections. Results:AMI model of forty white rabbits was successfully established to conduct longitudinal strain analysis, and 30 rabbits to conduct circumferential strain analysis because 10rabbits were excluded due to quality control requirement. The difference in HR between preoperative and postoperative was significant, but tIVST,LVPWT,LVDd,LAD and LVEF was not. The difference in three-layer GLS, GCS, global gradient-longitudinal stain(ΔGLS) and global gradient-circumferential stain(ΔGCS) was significant(P<0.001) and the value was lower than the preoperative one. The values of GLS and GCS were the highest in endocardium and the lowest in the epicardium(P<0.001). The value of long-axisin endocardium,mid-myocardium and epicardium of left lateral,anterior and anterior septum wall all showed a great decrease(P<0.05).The value of LS inthree-layer of inferior,posterior wall of left middle and apex sections was decreased after the operation(P<0.05). The value of LS in three-layer of posterior septum of basal,middle segment and inferior,posterior of basal segment decreased, but there was no significant difference(P>0.05). The value of CS in endocardium of left anterior,lateral,inferior wall of middle section and epicardium of anterior septum,posterior septum of basal section all showed a great decrease, and there was a significant difference(P<0.05). The rest sections of CS in three-layer had no significant difference (P>0.05), but the value measured postoperatively was lower than the preoperative one. Conclusion:To analysis LS and CS layer-specific strain of rabbits' LV sections in the early stage of AMI using 2D-STI can assess global and regional systolic function of LV in detail.
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