Assessment of left ventricular twist in rabbits with ventricular aneurysm formed by two-dimensional speckle tracking echocardiography

Abstract

Objective To evaluate the influence on left ventricular(LV) twist,and the relationship between LV twist and function in the rabbits with ventricular aneurysm formed after myocardial infarction by two-dimensional ultrasound speckle tracking imaging.Methods Twenty-six healthy rabbits were divided into two groups,six as control group,twenty as experimental group.The model of myocardial infarction and ventricular aneurysm were established by ligaturing left anterior descending coronary artery and left circumflex artery.After four weeks,according to the pathological examination of whether ventricular aneurysm formed or not,the experimental group was divided into myocardial infarct group and ventricular aneurysm group.Echocardiography was performed to measure rotations (at the levels of mitral annulus and apex in LV short-axis view),LV twist,left ventricular cavity size and function.Results Compared with the myocardial infarct group,LV end-diastolic diameter(LVEDD) and LV end-diastolic volume(LVEDV) were larger in the ventricular aneurysm group,but LV ejection fraction (LVEF),LV fractional shortening (LVFS),apical rotation and LV twist were lower in the ventricular aneurysm group than the myocardial infarct group.Both apical rotation and LV twist had shown a great correlation with LVEF.The conclusion was also shown in the ROC curve that sensitivity and specificity of diagnosis cardiac dysfunction were 76.9％ and 80.0％ respectively when the apical rotation was 1.21°.Conclusions There was a closely relationship between the change of apical rotation and the LV systolic function.When the apical rotation dropped to 1.21°,an apparent decline of LV systolic function was implied. Key words: Echocardiography; Heart aneurysm; Ventricular function,left; Rotation; Speckle tracking imaging