Comparison Of Anatomic M-mode, Tissue Velocity Imaging And Strain-rate Imaging In Quantification Of Regional Left Ventricular Function In A Rat Myocardial Infarction Model

BackgroundsAccurate quantification of regional left ventricular myocardialfunction is important in evaluation of the severity of coronary disease, and assessment of the prognosis and the therapeutic effectiveness. Unfortunately, not an adequate technique has been well validated and proven to be accurate yet, though there are lots of new echocardiographic methods being introduced for this propose.ObjectivesTo investigate alterations of parameters derived by three novel echocardiographic modalities of anatomic M-mode(AME), quantitative tissue velocity imaging(QTVI), strain and strain rate imaging (SI/SRI)during the process from myocardial ischemia to infarction, and to compare the relative values of three imaging modalities in detection and quantification of regional left ventricular systolic function; to explore whether the capabilities of detecting myocardial ischemia or infarction by three imaging modalities are affected by the size of myocardial infarction; and to establish the imaging settings and techniques in small experimental animals.MethodsWe created a rat model of myocardial ischemia/infarction by the procedures of open-chest operation and ligation of left anterior descending coronary artery (LAD) in 22 rats (MI-group), and 9 rats only with open-chest operation and without ligation of LAD (sham-operation) served as controls(CL-group). Echocardiography by using three different imaging modalities of anatomic M-mode, quantitative tissue velocity imaging, strain and strain rate imaging was performed pre-procedurally at baseline, and immediately, 2-week and 4-week after the procedures. The parametric measurements include systolic and diastolic thickness of regional left ventricle (WTs and WTd) and systolic thickening fraction of regional left ventricle(WTF) derived by AME, subendo-, subepi-, and transmural...