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

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120 min,分别检测结扎前、结扎后120 min、解除结扎后30 min、60 min、90 min、12 h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12 h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12 h相关性依然较好.结论 在AMI即刻及再灌注12 h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.

Abstract：

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.     

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

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.     

斑点追踪显像技术评价心肌缺血再灌注对心肌扭转影响的实验研究

目的 应用斑点追踪显像技术测定心肌缺血及再灌注后不同时刻的心肌扭转.方法 14只小型猪,随机分为两组:A组结扎前降支1 min,B组结扎前降支15 min.分别测定结扎前、解除结扎前及解除结扎后第1、5、30、60、90 min、1周各时间点常规心脏超声指标以及扭转数据,并进行比较.结果 缺血时A组心尖部及左室心内膜下扭转角度峰值再灌注后第1 min即恢复至基线水平;而B组相同扭转指标再灌注后30min出现一过性改善,相对于解除结扎前分别为(6.5±0.8).对(3.4±1.2).和(7.8±1.0)°对(6.1±1.1).(P均＜0.01),完全恢复则在再灌注后1周.B组心外膜下扭转角度峰值再灌注后呈逐渐上升趋势.结论 心肌缺血时间不同,再灌注前后心内、外膜下心肌扭转角度改变不尽相同.应用斑点追踪显像技术测定再灌注后心肌扭转恢复情况可以反映心肌缺血程度,从而为评价心肌缺血提供更长时间的观察窗.