目的:制备家兔急性心肌梗死再灌注模型，采用斑点追踪成像(speckle tracking imaging，STI)分层应变技术评价兔心肌梗死的环向心肌功能变化情况，探索ATP药物后适应的心肌保护作用。方法:40只兔分为2组：单纯缺血再灌注(ischemia reperfusion，IR)组与药物后适应(ATP-PostC)组。两组分别于冠状动脉阻断前、阻断后45 min、小剂量多巴酚丁胺负荷超声后、再灌注60 min及120 min进行图像采集，并获得如下参数：左室射血分数(LVEF)、心率(HR)、心内膜环向应变(CSsys-endo)、心肌环向应变(CSsys-mid)、心外膜环向应变(CSsys-epi)等。每组于阻断后及再灌注后不同时间段各处死5只实验兔进行病理学检查。结果:①冠状动脉阻断45 min后，两组兔LVEF及HR减低(均n P<0.05)，左室短轴水平心内膜环向应变(CSsys-endo)、心肌环向应变(CSsys-mid)、心外膜环向应变(CSsys-epi)绝对值明显减低(均n P<0.01)。小剂量多巴酚丁胺负荷后，两组兔短轴水平的CSsys-endo、CSsys-mid、CSsys-epi绝对值增高，与阻断后比较差异有统计学意义(n P0.05)。ATP-PostC组兔心肌短轴环向应变较阻断后增高(均n P<0.05)，ATP-PostC组各环向应变绝对值增高幅度明显高于IR组(n P<0.05)。ATP-PostC组内比较，再灌注各时间段的CSsys-endo绝对值与阻断后比较明显增加，差异有统计学意义(n P<0.05)；与再灌注60 min后比较，再灌注120 min后CSsys-endo、CSsys-mid绝对值继续增加(n P0.05)。再灌注后，ATP-PostC组各时间点梗死面积百分比较阻断后有所减少(均n P<0.05)。与IR组比较，再灌注120 min后ATP-PostC组梗死面积百分比较小，差异有统计学意义(n P<0.05)。n 结论:应用负荷应变超声分层可评估兔心肌缺血ATP-PostC模型再灌注前后左室心肌各层环向应变变化情况，识别及评价存活心肌功能，且ATP-PostC对心肌的再灌注损伤有保护作用。“,”Objective:To explore the application of speckle tracking imaging (STI) stratification strain technique in the assessment of circumferential myocardial function and the myocardial protection of ATP-postconditioning (ATP-PostC) in a rabbit model of acute myocardial infarction.Methods:A total of 40 rabbits were randomly divided into 2 groups: pure ischemia reperfusion group (IR group)and ATP-PostC group. STI images were recorded before and 45 min after occlusion of coronary artery, post low-dose dobutamine stress echocardiography, 60 and 120 min after reperfusion, respectively. The following parameters were obtained: left ventricular ejection fraction(LVEF), heart rate (HR), endocardial circumferential systolic strain (CSsys-endo), mid-myocardial circumferential systolic strain (CSsys-mid) and epicardial circumferential systolic strain (CSsys-epi) at left ventricular short-axis level. At different time points after occlusion and reperfusion, 5 experimental rabbits were killed in each group for pathological examination.Results:①Forty-five min after coronary artery occlusion in both groups, the values of LVEF and HR were decreased(n P<0.05), and the absolute values of CSsys-endo, CSsys-mid and CSsys-epi were significantly reduced(n P<0.01). After LDDSE, the absolute values of CSsys-endo, CSsys-mid and CSsys-epi were increased, which were different from those after blockade(n P0.05). After blockade, the absolute values of circumferential strains were increased significantly in the ATP-PostC group compared with IR group(n P<0.05). In the ATP-PostC group, the absolute values of CSsys-endo at different time points after reperfusion increased significantly compared with that after blockade (n P<0.05). The absolute values of CSsys-endo and CSsys-mid 120 min after reperfusion continued to increase significantly compared with those 60 min after reperfusion(n P0.05). The percentage of infarct areas at each time point of reperfusion in the ATP-PostC group was decreased compared with that after blockade(n P<0.05). Compared with the IR group, the percentage of infarct area in the ATP-PostC group was smaller after 120 minutes of reperfusion and the difference was statistically significant (n P<0.05).n Conclusions:The applications of STI stratification strain technique and LDDSE can assess left ventricular circumferential strains at each of myocardial layers before and after reperfusion in rabbit myocardial ischemia ATP-PostC model, identify and evaluate the function of viable myocardium, and exhibit the significant protective effects of ATP-PostC on myocardial reperfusion injury.