Study on the Position of the Electrical Heart Axis in Right Bundle Branch Block

Abstract

(1) The author advanced in this paper a method of determining the position of the electrical heart axis by comparing the standard limb leads with the unipolar limb leads. The axis can easily be pointed by the method within a relatively small angle (30°). (2) Many instances of electrocardiograms were studied by that method. The main point of the results obtained is as follows. The two axes named A₁ and A₂, which consist of the first and the latter halves of components of the mean electrical heart axis, respectively, are separate widely from each other in the instances of right bundle branch block (RBBB) which were observed by the author. On the other hand, A₁ and A₂ are close to each other in all of the instances of RBBB with left anterior hemiblock or left posterior hemiblock which were quoted from the paper by Rosenbaum et al.* Therefore, the instances observed by the author may be those of so-called pure RBBB. Such findings are to be added to the postulates for diagnosis of RBBB.