Nishian K, Naruse H, Kawakami K, Asakuma S, Tateishi J, Nomoto Y, Ohyanagi M, Yasutomi N, Fujitani K, Iwasaki T
First Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya.
J Cardiol. 1988 Mar;18(1):67-77.
To investigate the mechanisms and clinical significance of precordial (V1-V4) ST segment depression during acute inferior myocardial infarction, stress thallium-201 scintigrams and coronary angiograms were obtained within four to eight weeks after the onset of myocardial infarction in 37 patients experiencing their first acute inferior myocardial infarction. Among 18 patients with precordial ST depression (group 1), 11 with concomitant disease of the left anterior descending artery (LAD) had positive results on exercise test, whereas in seven patients without LAD lesion, only two had positive exercise test (p less than 0.01). In 19 patients without precordial ST depression (group 2), 11 had severe stenosis in the LAD. However, among these 11 patients, only two had positive exercise tests. Patients with precordial ST depression demonstrated a higher frequency of positive exercise tests than those without it (p less than 0.01). On stress thallium-201 scintigraphy, a perfusion defect involving the inferior wall was present in all patients, but additional anterior wall ischemia was present in only five of the 18 patients in group 1. These five patients had chest pain on exercise tests and a severe stenosis greater than 90% in the LAD. There was no significant difference in the frequency of additional posterolateral wall infarction between groups 1 and 2. In 18 patients in group 1, sigma ST (total degrees of ST segment depression in leads V1, V2, V3, and V4 in the acute stage) was significantly greater in 11 patients with LAD lesion than in seven without (p less than 0.05), and sigma ST greater than five mm was observed in 12 of 13 patients who had additional anterior wall ischemia and posterolateral wall infarction on stress thallium-201 scintigraphy (p less than 0.05). Myocardial revascularization, such as aortocoronary bypass surgery or percutaneous transluminal coronary angioplasty (PTCA), was performed in six of the 18 patients in group 1 in the chronic stage, but in only one of the 19 patients in group 2. Thus, in patients with initial acute inferior myocardial infarction, those with precordial ST depression seemed to be a high-risk group. It was suggested that, during the early stage of myocardial infarction, this abnormality on electrocardiograms is related to the summation of effects of anterior wall ischemia and posterolateral wall infarction. Furthermore, the sigma ST evaluation is useful in differentiating a mirror image of inferior wall infarction from anterior wall ischemia and posterolateral wall infarction as the mechanism of precordial ST depression.
为了研究急性下壁心肌梗死时胸前导联（V1-V4）ST段压低的机制及临床意义，对37例首次发生急性下壁心肌梗死的患者在心肌梗死后4至8周内进行了运动铊-201心肌显像和冠状动脉造影。在18例胸前导联ST段压低的患者（第1组）中，11例合并左前降支（LAD）病变者运动试验结果为阳性，而在7例无LAD病变的患者中，只有2例运动试验阳性（p<0.01）。在19例胸前导联无ST段压低的患者（第2组）中，11例LAD有严重狭窄。然而，在这11例患者中，只有2例运动试验阳性。胸前导联ST段压低的患者运动试验阳性频率高于无ST段压低者（p<0.01）。在运动铊-201心肌显像中，所有患者均有下壁灌注缺损，但第1组18例患者中只有5例存在额外的前壁缺血。这5例患者运动试验时胸痛，LAD狭窄程度大于90%。第1组和第2组之间额外后侧壁梗死的频率无显著差异。在第1组的18例患者中，11例有LAD病变者急性期V1、V2、V3和V4导联ST段压低的总和（σST）显著高于7例无LAD病变者（p<0.05），在运动铊-201心肌显像中有额外前壁缺血和后侧壁梗死的13例患者中，12例σST大于5mm（p<0.05）。在慢性期，第1组18例患者中有6例行心肌血运重建，如主动脉冠状动脉搭桥手术或经皮腔内冠状动脉成形术（PTCA），而第2组19例患者中只有1例行此手术。因此，在最初发生急性下壁心肌梗死的患者中，胸前导联ST段压低者似乎是高危人群。提示在心肌梗死早期，心电图上的这种异常与前壁缺血和后侧壁梗死的综合影响有关。此外，σST评估有助于区分下壁梗死的镜像与作为胸前导联ST段压低机制的前壁缺血和后侧壁梗死。
