The Spatial Vectorcardiogram Obtained by Use of a Trihedron and Its Scalar Comparisons

Abstract

The spatial vectorcardiogram is supposed to represent the path of the cardiac vector viewed from a rather large distance. With this in mind, the authors propose a vectorcardiographic method based on a trirectangular trihedron. Comparisons are made between calculated scalar leads derived from the spatial vectorcardiogram, and real scalar leads recorded from the subject. In case of concordance the hypothesis of a single instantaneous cardiac vector within an homogeneous conducting medium is verified. This was found to hold for most circumstances. However, for those instances in which discrepancies arose another hypothesis is advanced.

Comparative Studies in Vector and Linear Electrocardiography

“…Hence of 68 cases studied, the effect has been found to occur in all, and to be described by the distribution observed in the nine cases studied intensively. Duchosal and Grosgurin (1952) have plotted modified "cardiac centre" points to correct the calculated electrocardiograms to the observed leads, and in two cases the effective change in direction for best overall correction ae (for different segments of the loop) has been calculated to be 0'148 (radian), agreeing closely with the value (ae =0' 15) estimated experimentally.…”

“…In their monograph these workers report 23 cases; in all circumstances these cases have shown the effect, and numerous points from each of the cases have been plotted on the distribution curve ( Figure I). A further five cases reported by Duchosal and Grosgurin (1952), including two examples of extrasystoles, have been found to obey the relationship and representative points plotted.…”

Studies of the Spatial Vectorcardiogram in Normal Man

“…As indicated by Duchosal,22 the "electric dipole" of the heart shifts during the cardiac cycle and during respiration, not only because of events related to variations in the order of electric processes within the heart but also because of shifting of the heart within the chest as it beats. The influence of this changing position upon the configuration of the spatial vectorcardiograms and the spatial electrocardiograms has not been thoroughly evaluated.…”

“…This report is also intended to present certain aspects of the general problem of vectorcardiography, including a discussion of the reference system employed in these studies. MATERIALS AND METHODS Studies were made on 71 male and four female medical students between the ages of 22 and 33 years who had no evidence of cardiovascular disease. A teleoroentgenogram of the chest was obtained for each subject, and careful fluoroscopic examination of selected subjects was performed to determine, insofar as possible, cardiac position.…”

Information Contained in Vectorcardiograms

“…This "resolver" type computer has per mitted to integrate the precordial electrocardiograms, rather satis factorily, into the horizontal vectorcardiogram (17). The concept of equivalence between an EGG directly recorded potential and a potential with the same direction, calculated from the three vectorcardiographic components, had already been admitted (11).…”