Kanemoto N, Hosokawa J
Department of Internal Medicine, Tokai University School of Medicine, Kanagawa, Japan.
Jpn Heart J. 1992 Jul;33(4):423-35. doi: 10.1536/ihj.33.423.
We evaluated the relationship between the site of infarction and the infarct-related coronary arteries from electrocardiograms (ECGs) recorded early after the onset of chest pain in patients with an initial acute inferior myocardial infarction (IMI). The subjects were 80 patients (mean age 57 +/- 12 years) with IMI admitted within 6 hours from the onset of chest pain. This was prior to the thrombolytic era. We analyzed the ECGs on admission, at 24 hours and at 4 weeks. All patients underwent left ventriculography and coronary angiography at 4-6 weeks from the onset of the IMI. Left ventricular ejection fraction (EF) and regional area changes were measured. The infarct-related coronary artery was determined by the site of the asynergy. Patients were allocated into 2 groups according to the infarct-related artery, i.e. right (RCA, n = 52) and left circumflex (LCX, n = 28). Parameters measured were ST elevation, amplitude and width of R wave and R/S ratio in leads V1 and V2, and amplitude of U waves in leads V1 to V3. We defined the U wave as a prominent positive U wave (PPU) if it was > 0.5 mm (50 microV) in height. A significantly greater number of patients with PPU showed asynergy in posterolateral segments compared to those without PPU. The EF was significantly lower in patients with PPU than in those without (46 +/- 12% vs 54 +/- 13%, p < 0.05). Patients with PPUs eventually showed ECG evidence of posterior infarction (increased R wave duration and R/S ratio > or = 1 in lead V1 or V2) by 4 weeks compared to those without PPUs. Also a significantly greater number of patients with PPUs developed posterior infarction shown by left ventriculograms than those without PPUs. As to the infarct-related coronary arteries, a significantly greater number of patients with LCX disease showed concomitant posterior infarction than those with RCA disease. Also, a significantly greater number of LCX patients showed PPUs and ST elevations in leads V5 and V6 than those with RCA disease. The sensitivity of PPUs and ST elevations in leads V5 and V6 suggesting LCX disease was 60% and the specificity was 98% with a predictive accuracy of 87%. Therefore, we conclude that PPUs in leads V1-3 and ST elevations in leads V5 and V6 are specific markers for the diagnosis of LCX-related infarction in the setting of evolving IMI.
我们评估了初发急性下壁心肌梗死（IMI）患者胸痛发作后早期记录的心电图（ECG）梗死部位与梗死相关冠状动脉之间的关系。研究对象为80例胸痛发作6小时内入院的IMI患者（平均年龄57±12岁）。这是在溶栓治疗时代之前。我们分析了入院时、24小时及4周时的心电图。所有患者在IMI发作4 - 6周时接受了左心室造影和冠状动脉造影。测量了左心室射血分数（EF）和局部面积变化。梗死相关冠状动脉由心肌运动不协调部位确定。根据梗死相关动脉将患者分为2组，即右冠状动脉（RCA，n = 52）和左旋支（LCX，n = 28）。测量的参数包括ST段抬高、V1和V2导联R波的幅度和宽度以及R/S比值，以及V1至V3导联U波的幅度。如果U波高度>0.5 mm（50 μV），我们将其定义为明显正向U波（PPU）。与无PPU的患者相比，有PPU的患者后外侧节段出现心肌运动不协调的人数显著更多。有PPU的患者EF显著低于无PPU的患者（46±12%对54±13%，p<0.05）。与无PPU的患者相比，有PPU的患者在4周时最终出现后壁梗死的心电图证据（V1或V2导联R波时限增加且R/S比值≥1）。此外，与无PPU的患者相比，有PPU的患者经左心室造影显示发生后壁梗死的人数显著更多。关于梗死相关冠状动脉，与RCA病变患者相比，LCX病变患者发生后壁梗死的人数显著更多。此外，与RCA病变患者相比，LCX病变患者在V5和V6导联出现PPU和ST段抬高的人数显著更多。V5和V6导联PPU及ST段抬高提示LCX病变的敏感性为60%，特异性为98%，预测准确性为87%。因此，我们得出结论，V1 - 3导联的PPU以及V5和V6导联的ST段抬高是诊断进展期IMI中LCX相关梗死的特异性标志物。
