Assessment of the difference of myocardium strain between myocadial infarction and ventricular aneurysm by two-dimensional speckle-tracking imaging in rabbits / 中华超声影像学杂志

ABSTRACT

Objective To evaluate the difference of myocardium strain between myocadial infarction and ventricular aneurysm (VA) by two-dimensional speckle-tracking imaging in rabbits.Methods 26 healthy New Zealand white rabbits were enrolled in this study,6 were put into the control group and 20 in the experimental group.models of myocardial infarction concomitant with VA were prepared by the ligation of the middle segment of left anterior descending artery and left circumflex artery.At 4 weeks after the procedure,according to the pathological inspect and echocardiography for whether VA formed,the experimental animals were divided into the VA group and the myocadial infarction group.Echocardiography was performed to measure the LV cavity size and cardiac function.Radial strain rate (SrR) and circumferential strain rate(SrC) indexes were measured by 2D-STI software for each animal at the level of apex in left ventricular short-axis view,and then calculated the strain rate decrease percentage in each segment.Results 1)Compared with the control group,SrR-S,SrR-E,SrR A,SrC-S,SrC-E,SrC-A in all segments were reduced significantly in the VA group and the myocadial infarction group (P ＜ 0.05),the VA group was the most significant.2)Compared with the myocadial infarction group,the strain rate decrease percentage of SrR-S,SrR-E,SrR-A,SrC-S,SrC-E,SrC-A in all segment had significant in the VA group.Comparison between the each section,the strain rate decrease percentage of SrR-Santerior wall,SrR-Sateral wall,SrC-Santerior wall,SrC-Slateral wall were the most significant.3)There were the tighter relationship between the strain rate decrease percentage of SrR-Santerior wall,SrC-Santerior wall,SrR-Slateral wall,SrC-Slateral wall and left ventricular ejection fraction (r =0.82,0.72,0.75,0.71,repectively,all P ＜ 0.05).4) The ROC curve analysis showed that when the strain rate decrease percentage was 60％ as the critical point,the strain rate decrease percentage of SrC-Santerior wall,SrC-Slateral wall,SrR-Santerior wall,SrR-Slateral wall had a sensitivity of 83.30 ％,84.40％,83.30％,67.70％％ and a specificity was 73.60％,78.20％％,69.70％,83.30％ for prognosis ventricular aneurysm,repectively.Conclusions After ventricular aneurysm formation,anterior and lateral wall myocardial strain were give priority to the myocardial mechanics reconstruction,thus systolic myocardial strain rate decrease percentage can be important indicator of infarction myocardial developing into ventricular aneurysm.