Evaluation of effect of adenosine triphosphate postconditioning on myocardial ischemia reperfusion injury in rabbits using ultrasound speckle tracking imaging

Objective To evaluate the effect of adenosine triphosphate postconditioning on myocardial ischemia reperfusion injury in rabbits by ultrasound speckle tracking imaging(STI). Methods Forty-two healthy rabbits were randomly divided into three groups averagely: ischemia-reperfusion(IR) group, ischemia postconditioning(IPost) group, ATP-pharmacological postconditioning(PPost) group. The model of myocardial ischemia reperfusion was established. Echocardiography examinations were conducted before the coronary artery ligatured, after 45 min later and at the end of reperfusion. Pathological examinations were applied to detect the change of which two rabbits randomly selected from each group after the coronary artery ligatured 45 minutes later and the rests after reperfusion of 120 min. Results ①Ischemic and infarct changes could find in the six rabbits which were sacrificed after the coronary artery ligatured 45 minutes later. The same changes also could be found in the three groups after reperfusion, and the damage in IR group was the most significant. ②After block of coronary artery, left ventricular ejection fraction(LVEF) decreased in all groups (P<0.05) and STI index decreased in all groups (P<0.01). ③After reperfusion of 120 min later, global longitudinal systolic strain rate(GLSrsys), global longitudinal systolic strain(GLSsys) increased in IPost group and GLSrsys increased in ATP-PPost group, and longitudinal systolic strain rate(SrLsys), longitudinal diastolic strain rate(SrLd), longitudinal systolic strain(SLsys) increased both in IPost group and ATP-PPost group(P<0.05 or P<0.01). Compared in groups, GLSsys, SrLsys, SLsys in IPost group and ATP-PPost group all higher than those in IR group (P<0.05). Conclusions STI can evaluate exactly the global and regional myocardial function of rabbit myocardial infarct-reperfusion model and local index is better than overall index. STI can also detect correctly the protect effects on myocardial reperfusion injury of ATP. Key words: Echocardiography; Myocardial ischemia; Reperfusion injury; Postconditioning; Adenosine; Speckle tracking imaging