Studies on vectorcardiography Part Ⅰ. Basic studies on vectorcardiography by Kimura system with special reference to Frank system

Using a human torso model which had been made up with reference to normal stature of Japanese adult male and using four types of elliptical cylinder model which have different longitudinal diameter, Kimura system and Frank system were studied from the standpoint of transfer impedeance, and following results were obtained. 1) In Kimura system, elevation of transfer impedance of X and Z leads deviated to upward about 15 degrees in comparison with the latter. Nevertheless, the former's orthogonality was maintained relatively well, and have been scarcely affected by the type of elliptical cylinder. 2) In Frank system, according to narrowing of longitudinal diameter of thorax, orthogonality of X and Z leads became worse and included angles of their transfer impedance became narrow. 3) In Kimura system, the ratio of transfer impedance of X to Y leads was about 1:3 in each model, therefore, frontal plane vectorcardiogram of Kimura system could be useful for diagnosis of cases whose heart-electromotive forces change vertically. 4) Much axis deviation could not be caused by the changes of position of artificial current dipole and longitudinal diameter of the thorax