The subject of the electrical axis of the heart has been receiving more and more attention in recent years. In the first edition of Lewis' work "The Mechanism of the Heart Beat"1 it is not mentioned. Considerable attention, however, is given the subject in the second edition.2 It is not too much to say that a thorough understanding of the relations of the axis is a necessary foundation of knowledge of apparently simple features of the electrocardiogram. This paper has for its purpose the presentation of a new method of evaluating the electrical axis, and a brief discussion of some aspects of the study of the subject.
By the term "electrical axis" is meant the line along which the resultant of the electrical forces acting in the heart at any instant is expressed. Or, from another point of view, it corresponds, as Lewis puts it,2 to "the average direction
DIEUAIDE FR. THE DETERMINATION AND SIGNIFICANCE OF THE ELECTRICAL AXIS OF THE HUMAN HEART. Arch Intern Med (Chic). 1921;27(5):558–570. doi:10.1001/archinte.1921.00100110043002