Electrocardiographical and electron-microscopical Changes in the early Stage of coronary artery Ligation

　Electrocardiographic and morphological changes in the early myocardial infarction were presented in 14 adult male dogs.

　1) On even the earliest stage of myo-cardial ischemia, when hiterto, a detectable change has never been recognized in the histological examination, remarkable pat-hological changes of the myocardium i.e. swelling of mitochondrias, destruction of myofibrills, lightending of sarcoplasma and intacellular edema appear on the electron-microscopic figures.

　2) Comparing electrocardiographical al-terations with histological changes in early myocardial infarction, the more intense the myocardial swelling and edema of the affected region progress, the larger the PS-T segment deviation in E.C.G. becomes ; then the severer the coagulation necrosis, the smaller the RS-T segment deviation. The "cove-plane T wave" or the "coronary T wave" in electrocardiogram developes at the end of the coagulation necrosis stadium of morphological examination.

　3) It seems that stages of electrocardio-graphic alterations after coronary occlusion correspond to stadiums of morphological changes in the affected myocardium in our experiment : i, e, on the acute stage of electrocardiographic examination, the myocardium shows the figure of the initial stadium of the coagulation necrosis stadium of histological examination ; on the subacute stage of E.C.G., the stadium of cellular infiltration ; on the chronic stage of E.C.G., the stadium for healing, respectively.

　Prof. F. Takagi, Director of the Department of Pathology, Tokyo Jikeikai School of Medicine, provided technical assistance on the electronmi-croscopical examination in this experiment.