心筋梗塞の心電圖(第3報) : 外側壁梗塞

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In the previous report, the author described the general observation of the electrocardiographic changes in 35 autopsied cases of myocardial infarction. In an attempt to correlate the findings in the electrocardiogram of infarction in each portion of the ventricular wall with the post-mortem findings, the author took up and discussed the anterior infarction in Part II of this serial study. In this communication, the findings in the electrocardiograms have been analyzed and correlated with the pathologic findings in 20 cases with lateral infarction in this series of 35 cases. Of these 20 cases, one had a infarction confined to the lateral wall of the left ventricle. In 12 cases, anterior infarcts extended into the lateral wall of the left ventricle, and in 7 cases, posterior infarcts invaded into the lateral wall of the left ventricle. Of these 20 cases, one had a recent infarction, 19 had healed infarctions, but in 2 of the latter, the infarctions were proved to be of relatively fresh one by microscopic examination, and in at least 8 cases of the latter, the electrocardiograms, were obtained also in the acute stage. The cases were classified into the following three groups, according to the location and extent of the lesion in the lateral wall at autopsy: (A) the infarction involving the apical pne-third or more of the lateral wall, (B) the infarction involving the apical one-fifth or more and less than the apical one-third of the lateral wall, and (C) the infarction involving the middle one-third of the lateral wall. 1. Group A included 13 cases. In 2 cases of 3 transmural infarctions in group A, a QS complex was recorded in one or more of Leads V_5, V_6 and V_7. In 3 of 10 subendocardial infarctions, an abnormal QR(S) complex and a inverted T wave and/or depression of RS-T segment were obtained in one or more of Leads V_5, V_6 and V_7. (in one case in Lead CF_5). An abnormal Q wave could not be found and only depression of the RS-T segment and/or inversion of T wave were present in the left precordial leads in another 7 cases of these subendocardial infarctions, except one case in which the number of the employing leads was insufficient. Consequently, it was shown as difficult to differentiate left ventricular hypertrophy, coronary insufficiency and others by means of the electrocardiographic examination in these cases. 2. Relatively small apical infarction of the lateral wall which was classified into group B was found in 4 cases. One of these cases was a tarnsmural infarct and 3 were subendocardial infarcts. In one case of the latter, a borderline Q wave with a notched upstroke of the succeeding R wave was found in Lead V_5. And the electrocardiogram of these 4 cases displayed a depression of the RS-T segment and an inverted or a frat T wave in one or more (in most cases in two or more) of Leads V_5, V_6 and V_7. 3. In one posterolateral infarction of 3 cases which was classified into group C, the electrocardiogram displayed right bundle branch block and was accompanied by an abnormal Q wave in Lead V_7 and by a depressed RS-T segment in Lead V_5. In another 2 cases of this group, the infarct was patchy and relatively small, and the electrocardiogram recorded only slight depression of RS-T segment in Leads V_4, V_5 and V_6, without an appearance of an abnormal Q wave. 4. Of all 20 cases of the lateral infarction, the abnormal Q wave in the left precordial leads was observed in 5 cases, and the borderline Q wave in only 2 cases. In another 13 cases an abnormal Q waev could not be found. The reason of the absence of an abnormal Q wave was discussed. In respect to this problem, it must be concluded that the infarction was limited to the subendocardial layer in the lateral wall in 15 of these 20 cases. In some cases the displacement of the transitional zone to the left, the presence of other extensive infarction elsewhere in the left ventricule and/or the patchy infarction was noted as a cause of this fact. It was also considered that the distance between the location of the precordial lead and the epicardial surface in the lateral wall was much longer than distance from the anterior wall of the left ventricle to the precordial electrode. 5. In 14 Cases of this series, displacement of RS-T segment was present in the left precordial leads, and in 13 of these 14 cases the RS-T segment was depressed in these leads. Elevation of the RS-T segment was observed in only one case of transmural infarction. RS-T depression in the right precordial leads was also found in only one case in this series. 6. In 2 of 15 cases in which the augmented unipolar limb leads were obtained, an abnormal Q wave or a borderline Q wave was recorded in Lead _aV_L and was accompanied by an inverted or a flat T wave in the same lead. In another 9 of these 15 cases, Lead _aV_L displayed only RS-T variations (that is, RS-T depression and inversion or flatness of the T wave), without signigcant QRS abnormalities. 7. Abnormal Q waves in Leads CF_3, CF_4 and CF_5, which were suggestive of anterolateral infarction, were found in one case in which the infarct was limited to the lateral wall, as a result of marked counterclockwise rotation of the heart about its longitudinal axis. 8. Tall R waves in right precordial leads were found in 2 cases, and an prominent or tall R wave in Lead _aV_R was found in another 6 cases of this series. In each of latter cases, autopsy revealed a large anteroposterior infarction. 9. Of this series of 20 cases, an abnormal infarct-Q wave was recorded in Lead I in only 3 cases.
社団法人日本循環器学会の論文
1955-01-20

心筋梗塞の心電圖(第3報) : 外側壁梗塞

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