Computer analysis of the non-angular parameters of the QRSsE loop and orthogonal lead QRS characteristics in...

The canine modification of the Axial lead system of McFee and Parungao was used to record the VCG from 38 necropsy-verified normal dogs. Characteristics of the QRSsE loop were analyzed by a FORTRAN program on the IBM 360/75 digital computer. The following non-angular parameters were characterized for the normal dog: loop areas in the frontal, sagittal, and transverse planes; time duration of QRS; time integral of QRS; peak spatial magnitude; spatial velocity; eigenvalues and eigenvectors. It was shown that the normal QRSsE loop was extremely planar, but of variable length and width. Vector lengths at nine points in each plane were determined. Extreme absolute and percentage variation existed in all vector length parameters. The orthogonal lead characteristics were described. A consistent finding was a Q wave in lead Vx in all subjects. An S wave was present in this lead in 50% of the dogs. In lead Vy a Q wave was found in 81.6% of the dogs and an S wave was present in 94.7%. In contrast to the consistency of the angular parameters found in this same group of dogs which was reported earlier, the non-angular parameters and orthogonal characteristics could not generally be defined over small ranges.