犬急性透壁性心肌梗死极早期心电图变化的实验研究

Electrocardiographic changes in the hyperacute stage of acute myocardial infarction in canine

目的:观察急性心肌梗死(AMI)极早期心电图的变化,并着重观察缺血性J波的发生情况及其与心律失常发生的关系,为临床早期诊断AMI提供依据。方法:杂种犬19只,开胸结扎前降支造成前壁急性心肌缺血,观察结扎前和结扎后2h内心电图变化。结果:超急性期约42%犬出现缺血性J波。T波高尖发生率为84%。ST段抬高发生率100%,全部累及胸前导联。巨R波发生率16%,出现晚于T波高尖和ST段抬高。以上心电图变化均出现在前壁,与梗死部位一致。AMI超急性期心电图变化中T波高尖和缺血性J波出现最早,ST段抬高次之,R波变化出现最晚。冠状动脉前降支结扎造成前壁心肌梗死后58%的犬至少有1次室性心动过速(VT)发生,26%发生心室颤动(Vf)死亡。前30min内发生的VT占总数的70%,与后90min比有显著性差异(P<0.01)。出现J波的犬中全部发生VT,37.5%出现Vf;未出现J波的犬中27%出现VT,2只出现Vf。J波组VT较非J波组明显增加(P<0.05)。结论:结扎前降支所致AMI超急性期心电图可出现缺血性J波、T波高尖、ST段抬高和巨R波型,缺血性J波是提示急性心肌缺血的心电图新指标,同时缺血性J波的出现常提示心电活动不稳定,易发生VT和Vf。

Objective：To study electrocardiographic changes in the hyperacute stage of acute myocardial infarction in canine.Method：It included 19dogs whose anterior descending branch was ligated through thoracotomy to induced anterior acute myocardial ischemia.ECG was recorded before and after ligation within two hours.Result：In the very early stage of AMI,peaked T wave often showed first with the incidence rate of 84percent.Ischemic J wave appeared before ST-segment elevation with the incidence rate of 42percent.ST-segment elevation appeared in all dogs after ligation.It appeared earlier and lasted for a long time.Giant R-wave occurred in 16percent of the dogs of AMI.ECG change appeared at anterior wall coherent to area of MI.At least one ventricular tachycardia occurred in 58percent of the dogs after MI and 26%had ventricular fibrillation and died.In the first 30minutes ventricular tachycardia occurred much more than those in later 90minutes.All dogs had ventricular tachycardia in J-wave group and 37%of them had ventricular fibrillations,which were more than non J-wave group.Conclusion：In the very early stage of AMI ECG often showed peaked T wave,ischemic J wave,ST-segment elevation and the Giant R wave.Ischemic J wave,as a new index ECG of myocardial ischemia,prompted instability of heart and proned to ventricular tachycardia and ventricular fibrillation.