Study on vectorcardiogram of normal Japanese male adults, with reference to T loop

Abstract

Recently the Frank lead system has been chosen in our country as a common method for recording spatial vectorcardiograms among a number of lead systems. Several studies on normal Frank vectorcardiograms have been reported. They were, however, focused on analysis of QRS SE loops, and few detailed studies were found in the literature. In the present study an attempt was made to establish normal ranges for various parameters of TSE loops. The material consisted of 1 16 normal male adults with the ages ranging from 20 to 35 years (the average age of 2 7.5 years). A11 vectorcardiograms were recorded with the Frank lead system and the chest electrodes were arranged at the 5th intercostal space at the sternum. The frontal, horizontal and left sagittal planar loops were simultaneously photographed on 35-mm films. Enlarged prints were used for exact and easy measurements. The following quantitative and qualitative parameters were analysed. I Analysis of three planar projection T and QRS loops. i) Directions and magnitudes of maximum T and QRS vectors. (Fig. 1) ii) T-QRS angles-maximum T vector angle minus maximum QRS vector angle in each plane. iii) T/QRS ratios-magnitude ratios of the maximum T vector to the maximum QRS vector in each plane. iv) Width of T loops-it was considered positive when the T loop was inscribed counter-clockwisely and negative when this rotated clockwisely. v) W/L ratios of T loop-ratios of width to magnitude of the maximum vector for the T loop. vi) Configuration of T Ioops. II Analysis of spatial T and QRS vectors. i) Spatial polar coordinates of spatial maximum T and QRS vectors (Fig. 2). ii) Spatial T-QRS angles-spatial angles between both spatial vectors. iii) Spatial TIQRS ratios-magnitude ratios of spatial maximum T vector to spatial maxi-mum QRS vector.