Abstract
Prof. MAEKAWA proposed Rectangular Isosceles Triangle Coordinate, which is considered more true to nature than Einthoven's Triangle Scheme. According to this coordinate, the right arm and left leg lead points constitute the both apexes of the hypotenuse of this triangle. When the magnitude of the potential of each limb lead point is designated ΦR, ΦF and ΦL, respectively, ΦR=-(II)/2, ΦF=(II)/2, ΦL=(I-III)/2.We have studied merits and demerits between the both coordinates, theoretically and practically. The results are as follows.(1) Mathematical relationship is found between the results analyzed by Einthoven's Triangle and those by Maekawa's Rectangular Isosceles Triangle Coordinate. (i) The vector rotation in a cardiac cycle is in the same direction, whether analyzed by the former or by the latter. (ii) The magnitude of the vector potential on the frontal plane analyzed by Einthoven's Triangle is 1.15-0.67 times greater than that by Maekawa's Coordinate.(2) When the magnitude of the potential of the central terminal is designated V0 in Eithoven's Triangle and Φ0 in Maekawa's Coordinate, respectively, V0-Φ0=VL/2=ΦL/3 Consequently, when VL≒0 or ΦL≒0, V0≒Φ0 (3) In clinical practice, Rectangular Isosceles Triangle Coordinate is more convenient and of more value in comparison with Einthoven's Triangle Scheme, mostly because the former is a rectangular coordinate.
