斑点追踪显像技术评价心肌扭转与心肌梗死范围相关性的实验研究

Study of relationship between myocardial infarction size and left ventricnlar torsion by speckle tracking imaging

目的应用斑点追踪显像技术评价急性心肌梗死（AMI）再灌注前、后左室心肌扭转，借以比较多个常规扭转指标与梗死范围的相关性，找出最能反映梗死范围的扭转指标。方法小型猪15只，结扎左前降支120min，分别检测结扎前、结扎后120rain、解除结扎后30min、60min、90min、12h各时间点常规超声指标以及扭转数据并进行比较。氯化硝基四氮唑蓝染色后计算心肌梗死范围。结果AMI后心尖及左室各旋转／扭转角度指标均显著下降，再灌注12h无明显改善。AMI即刻，左室整体扭转角度峰值及心尖整体旋转角度峰值与梗死范围的相关性明显优于同期其他扭转指标，相关系数分别为-0．81和-0．69（P均〈0.01）；再灌注12h相关性依然较好。结论在AMI即刻及再灌注12h内，左室整体扭转角度峰值及心尖整体旋转角度峰值是反映心肌梗死范围最敏感的扭转指标。

Objective To investigate the most sensitive markers of left ventricular（LV） torsion which can reflect infarct size by assessing the relationship between routine markers of LV torsion and infarct size using speckle tracking imaging （STI）. Methods Fifteen open-chest pigs underwent 120 minutes of left anterior descending （LAD） ligation followed by 12 hours of reperfusion. Rotation and torsion of LV were obtained by STI before LAD occlusion, LAD occlusion immediately, and 30,60,90 minutes and 12 hours after reperfusion. Infarct size was measured by nitrotetrazolium blue chloride staining. Results LAD ligation resulted in a dramatic decrease in both subepicardial and subendocardial peak apical rotation or peak LV torsion. Twelve hours after reperfusion, all of the peak rotation and torsion remained significantly reduced （P〈0.01 versus AMI）. At AMI, peak bulk LV torsion and peak bulk apical rotation inversely correlated with infarct size （ r=-0.81, P %0.01 ; r = - 0.69, P 〈0.01）. There existed the good relationship at 12- hour follow-up after reperfusion. The relationship was superior to that of other torsion markers. Conclusions Peak bulk LV torsion and peak bulk apical rotation are the most sensitive markers of LV torsion which can reflect infarct size.