应用斑点追踪技术对急性心肌缺血及再灌注心肌应变功能的研究

摘要

Objective This study aims to detect circumferential strain of subendocardial and subepicardial myo cardium in acute myocardial ischemia and reperfusion by speckle tracking imaging.Methods Left anterior decending coronary (LAD) of 20 healthy adult hybrid dogs were ligated and circumferential strain of subendocardial and subepicardial myocardium were compared at basal,papillary muscle and apical level in different time (before ligation,ligation immediate,60,120 and 180 minutes after ligation,reperfusion immediately,60 and 120 minutes after reperfusion).Results (1)Circumferential strain of myocardium at basal level increased(P＜0.01) in acute myocardial ischemia.Circumferential strain of myocardium at papillary muscle and apical level decreased(P＜0.01) and reverse movement of myocardium even occurred at apical level.After reperfusion,circumferential strain of myocardium declined at basal level(P＞0.05) and increased at papillary muscle and apical level(P＜0.01,P＜0.05),which was still lower than that of the basic status.(2)Subendocardial myocardium was more sensitive to ischemia in the process of acute ischemia and reperfusion.(3)Myocardial reperfusion injury occurred after reperfusion.Conclusions Speckle tracking imaging plays an important role in quantitative evaluating cardiac function,determining infarction extent of transmural myocardium and evaluating the efficacy of coronary recanalization treatment.%目的 应用斑点追踪技术(STI)检测急性心肌缺血及再灌注不同时间点心内膜下心肌和心外膜下心肌圆周应变的改变.方法 选取20只健康成年杂种犬,结扎左冠状动脉第一对角支,分别对结扎前、结扎即刻、结扎60、120 min和180 min及再灌注即刻、60 min和120min、基底水平、乳头肌水平和心尖水平心内膜下心肌和心外膜下心肌的圆周应变进行比较.结果 (1)在急性缺血过程中基底水平心肌圆周应变上升(P＜0.01).乳头肌水平和心尖水平心肌圆周应变下降(P＜0.01),心尖水平心肌甚至出现反向运动.再灌注后,基底水平圆周应变下降,无统计学意义(P＞0.05),乳头肌水平和心尖水平圆周应变上升(分别为P＜0.01,P＜0.05),但仍低于基础状态.(2)在急性缺血及再灌注过程中,心内膜下心肌对缺血更加敏感.(3)再灌注后心肌出现再灌注损伤.结论 斑点追踪技术可以客观定量局部及整体的心脏功能并判断心肌梗死的透壁程度及评价冠脉再通后的疗效.