Changes of left ventricular myocardial function in the early stage of acute myocardial ischemia in rabbits using speckle tracking imaging and myocardial contrast echocardiography
Objective:Combined speckle tracking imaging(STI)and myocardial contrast echocardiography(MCE)to evaluate myocardial function of left ventricular(LV)in the early stage of acute myocardial ischemia(AMI)in rabbits by measuring the LV strain and myocardial perfusion parameters. Methods:A total of 36 New Zealand white rabbits were enrolled in this experiment,the LV branch of coronary artery was ligated in order to establish an AMI model. In the low MI mode,15 cardiac cycles of parasternal LV long-axis,apical four-,three- and two-chamber views were acquired before operation(which was called the preoperation group)and 10 minutes after AMI(which was called the postoperation group)for analysis. Global and segmental peak systolic longitudinal strain(LS)of LV walls was analyzed by STI. Myocardial blood volume(A),velocity(β)and myocardial blood flow(MBF)were analyzed by MCE. Results:There were significant differences in GLS and LS of left anterior septum wall,anterior wall,lateral wall,posterior wall,inferior middle wall,and apex sections between the preoperation and postoperation groups,the values in the postoperation group were significantly lower than those in the preoperation group(P<0.05). The myocardial perfusion parameters of LV between the postoperation and preoperation groups had significant differences(P<0.05)except the A value of inferior and posterior septum wall. The changes of LS percent were positively correlated with MBF of left anterior septum,anterior,lateral,inferior,posterior,and posterior septum walls(r were 0.58,0.56,0.65,0.62,0.56,0.36,P<0.05). Conclusion:Combined STI and MCE can reflect the changes of LV myocardial function in the early stage of acute myocardial ischemia sensitively.