急性冠不全時の壁内誘導心電圖に關する實驗的研究

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Changes in intramural lead ECG's, which follow acute obstruction of the coronary flow, were studied using a specially designed intramural electrode which permitted the operator to record six leads simultaneously.Marked ST deviation, due to local injury was observed immediately after the insertion of the electrode, thus producing a monophasic wave. This injury current receded however after 10 to 20 min. When the ECG became stable but with a slight ST deviation, the coronary artery was ligated and later released. Serial changes in the ECG's were observed when the coronary artery was ligated and later released.The QRS complex in the stable condition showed a QS pattern at the subendocardium (1/3 to 1/2 of the whole thickness) and at outside the subendocardium, rS, RS, or Rs pattern. This observation agreed in principle with the experiments performed by Prinzmetal.In most cases, the ST segments were gradually elevated immediately after ligation, and the ST deviations became maximum after approximately 3 minutes while the QS waves in the subendocardium and the S waves in the subepicardium became small, or disappeared. In some cases the ST elevations continued for quite some time after 3 minutes, and in other cases the ST elevated very rapidly. In the two latter situations, ventricular fibrillation was often induced by releasing ligation or merely by touching the inserted electrode.When the coronary artery was ligated near the base, ventricular fibrillation nearly always occurred and sometimes it occurred even by ligation at the mid portion of the anterior descending branch.From this experiment, it was impossible to decide whether or not the St deviation preceded or followed the T inversion after ligation. Changes, which occurred after the release of ligation, followed the reverse course of those after ligation, i.e. : the ST elevation receded and the QS or S wave became deeper and returned to the initial pattern after approximately 2 to 3 min., but occasionally even in as short a time as 30 seconds. The difference in the amplitude of the ST deviation by ligation between subepicardium and subendocardium was not constant in our experiment. Cases in which the ST deviation was greater in the subendocardium than in the subepicardium were more frequently observed and were in the ratio of 3 to 1 respectively.By means of injecting India ink into the ligated artery, the relationship between the stained portion and the location of the electrode, was investigated and correlated with electrocardiographic changes. The staining of the inner, middle, and outer layers of the cardiac wall and of the endocardium and epicardium was not uniform and in some individual cases quite different : namely, spot-like, patchy, or string-like. In some cases the stain appeared to completely permeate the cardiac wall; however, unstained parts were actually scattered throughout the stained area. On occation the ligation of an artery which did not appear to supply the area where the electrode had been inserted gave the expected results rather than an artery which was thought to supply this area. As Moore found in dogs, the course of the coronary artery was complicated and anastomosing branches were rather well developed; consequently, it was difficult to predict which artery supplied the infarcted area.An ECG recorded from an electrode in the stained area showed a marked ST elevation, whereas the ST deviation was very slight i. e. on an ECG recorded from an electrode in the unstained area. It was clearly recognized that an injured area having a ligation of the coronary artery was clearly distinguished from an uninjured area and the injured area showed ST deviations.The amplitude of the ST deviation varied with size and location of the injured area. In an uninjured area adjacent to an injured area, the ST deviations were very small, and it was difficult to decide whether or not the little injury current was due to the ligation or the residual effect of the electrode being inserted.It was found that there was a relationship between electrocardiographic changes due to the location of the electrode and the condition of coronary circulation. Contrary to the reports of many investigators, injury due to coronary insufficiency or ligation of the main coronary artery did not necessarily occur in the endocardial side.The experimental results show that changes in ECG's were in close agreement with the results of potential calculations in a heart model.Injury which occurs in trasient coronary insufficiency due to the ligation of the coronary artery is very complicated, thus, it is difficult to evaluate the condition of the injured heart muscle by means of the ordinary leads such as an precordial, epicardial or endocardial direct lead. It is only possible to evaluate this conditions through the use of an intramural lead.
社団法人日本循環器学会の論文
1958-11-20

急性冠不全時の壁内誘導心電圖に關する實驗的研究

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