NORMAL VECTOR MAGNETOCARDIOGRAM .1. CORRELATION WITH THE NORMAL VECTOR ECG

The vector magnetocardiogram (VMCG) has been measured with the correct ed unipositional VMCG lead system and analyzed statistically in 290 no rmal subjects. The morphologic study of the QRS waveforms showed that in the right-to-left (X) component, the triphasic QRS waveform appeare d in 55% of the subjects. The superoinferior (Y) component was charact erized by a prominent S wave in 96% of the subjects, and the anteropos terior (Z) component was also characterized by a prominent S wave in 9 5%. The VMCGs were compared with the vector electrocardiograms (VECG) recorded in a subgroup of 200 subjects, in whom both the VMCG and VECG were available for computer analysis. The normal variability of the s patial vector magnitude measurements was significantly greater in the VMCG than in the VECG. Some similarities were observed in the waveform s of the time-averaged QRS complexes between the VMCG and VECG. Multip le linear regression analysis between the VMCG and VECG showed that ma ximally 27, 45, and 41% of the variation in the instantaneous QRS X, Y , and Z amplitudes of the VMCG, respectively, could be explained by th e instantaneous X, Y, and Z amplitudes of the VECG.