急性下壁心肌梗死心电图ST段抬高Ⅲ导大于Ⅱ导对判断梗死相关动脉的意义

Usefulness of ST-segment elevation in lead Ⅲ exceeding that of lead Ⅱ for identifying the infarct-related artery in inferior wall myocardial infarction

目的 探讨急性下壁心肌梗死心电图ST段抬高Ⅲ导大于Ⅱ导对判断梗死相关动脉的意义。方法 分析84例首发急性下壁心肌梗死病人心电图及冠状动脉造影的结果。结果 ST段Ⅲ/Ⅱ>1组中89%的病例心肌梗死相关动脉为右冠状动脉(RCA),ST段Ⅲ/Ⅱ≤1组中35%的病例为RCA,两组有显著差异,P<0.01。ST段Ⅲ/Ⅱ>1组中11%的病例为回旋支(LCX),ST段Ⅲ/Ⅱ≤1组中65%的病例为LCX,两组亦有显著差异,P<0.01。ST段Ⅲ/Ⅱ>1组在RCA为梗死相关动脉的54例病例中30%为RCA近段,48%为RCA中段,22%为RCA远段,ST段Ⅲ/Ⅱ>1对近中段的阳性预测值为78%,阴性预测值为38%。同时,在合并右心室心肌梗死中94%的病例ST段Ⅲ/Ⅱ>1,敏感性为94.1%,特异性为32.8%。结论 ST段Ⅲ/Ⅱ>1及ST段Ⅲ/Ⅱ≤1可分别作为判断RCA及LCX为梗死相关动脉的较为可靠的指标。

Objective To evaluate the significance of ST-segment elevation in lead Ⅲ exceeding that of lead Ⅱ for i-dentifying the infarct-related artery in inferior wall myocardial infarction. Methods The electrocardiograms and coronary angiographic films of 84 patients with inferior wall AMI were analyzed. Results In the group of ST-segment elevation in lead Ⅲ exceeding lead Ⅱ(Ⅲ/Ⅱ>1),89% and 11% cases were proved to have occlusions of right coronary artery (RCA) and left circumflex (LCX) respectively, while 35% and 65% cases were proved to have RCA and LCX respectively in the group Ⅲ/Ⅱ≤1. Significant difference was revealed (P<0. 01). The positive predictive value of ST elevation in lead Ⅲ exceeding that of lead Ⅱ correlating with a lesion in proximal or mid RCA was 78% with a negative predictive value of 38%. 94% cases with ST-segment elevation in lead Ⅲ exceeding that of lead Ⅱ have inferior wall AMI and right ventricular infarction together. The sensitivity was 94.1% and specificity was 32. 8%. Conclusion ST-segment elevation in lead Ⅲ exceeding or not exceeding lead Ⅱ is a powerful predictor of occlusion of RCA or LCX respectively in patients with inferior wall AMI.