The Electrocardiogram in Myocardial Infarction : PART I. GENERAL OBSERVATION

Abstract

A correlative study of electrocardiographic and post-mortem findings was performed on 35 cases of myocardial infarction. It is emphasized that special attention was paid to describe precisely the extent and localization of lesions in myocardium. In few cases, electrocardiograms were obtained by the standard limb leads, from two to five CF leads, and the Nehb's leads, and in the majority, the standard limb leads, the multiple unipolar precordial leads (Wilson), the augmented unipolar limb leads (Goldberger), and the Nehb's leads were employed. Of 35 cases, 4 were recent and 31 were healed infarctions. As to the size of these infarctions, even the smallest one of them was well over 2 centimeter in diameter. To avoid the confusion about the extent and location of infarction, the author divided the ventricular wall into the following six portions, as shown in Fig.1.: right ventricular wall, inter-ventricular septum, and anteroseptal portion, anterior free wall, lateral wall and posterior wall of the left ventricle. 1. Of 35 cases, 26 cases (74.2 per cent) were diagnosed as infarction and 4 were suspected of infarction by the electrocardiographic changes which were mainly consisted of the abnormal Q wave and occasionally of RS-T variations. The five cases which showed no sign of infarction in the electrocardiograms, were consisted of one posterior infarction, one infarction in the posterior wall of the left ventricle and the posterior portion of the inter-ventricular septum, one subendocardial anterolateral infarction, one patchy infarction confined to the anteroseptal portion and the anterior free wall of the left ventricle, and one relatively small infarction of the apex of the left ventricle. 2. The precise localization of the infarction was demonstrated by the electrocardiograms in only 11 cases, but in 24 cases (68.6 per cent) possible location was more or less predicted by the electrocardiographic pattern. In all of 4 suspected cases, postmortem examinations proved the correct diagnosis about the locaion of the infarction. Accordingly, it can be said that in almost all cases in which the electrocardiographic patterns were diagnostic or suggestive of infarction, the localisation of infarction was diagnosed correctly. it must be stressed however that there was aslo noted the fact that the lesions in the posterior wall, especially in the apical portion in anteroposterior infarction, in the posterior portion of the septum in posteroseptal infarction, and in the lateral wall in the posterolateral or anteroposterior infarction of the left ventricle failed frequently to be associated with the diagnostic signs of infarction. 3. Diagnostic signs of infarction were found in the standard limb leads in only 13 cases, 37.1 per sent of all cases. In 17 cases, that is, in about half of all cases, the standard limb leads were not diagnostic nor suggestive of infarction. Even in the cases in which the standard limb leads were already diagnositc of infarction, the extent and location of infarcts was demonstrated more accurately by the unipolar leads. 4. As to the Nehb's Lead D was considered valuable in the diagnosis of infarction. In some cases of the posterior infarction in which the diagnostic sign of infarction was not obtained in Leads _aV_F, II and III, Lead D showed the pattern diagnostic of infarction. 5. The so-called T_1<T_3-pattern (Dressler et al.) was observed in 9 cases (25.7 per cent of all cases). In each of them the unipolar leads indicated the distinct diagnostic signs of infarction. Therefore, the T_1<T_3-pattern had only a limited value in establishing a diagnosis of infarction.