Normal vector magnetocardiogram. I. Correlation with the normal vector ECG.

The vector magnetocardiogram (VMCG) has been measured with the corrected unipositional VMCG lead system and analyzed statistically in 290 normal subjects. The morphologic study of the QRS waveforms showed that in the right-to-left (X) component, the triphasic qRs waveform appeared in 55% of the subjects. The superoinferior (Y) component was characterized by a prominent S wave in 96% of the subjects, and the anteroposterior (Z) component was also characterized by a prominent S wave in 95% . The VMGs 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 spatial vector magnitude measurements was significantly greater in the VMCG than in the VECG. Some similarities were observed in the waveforms of the time-averaged QRS complexes between the VMCG and VECG. Multiple linear regression analysis between the VMCG and VECG showed that maximally 27, 45, and 41% of the variation in the instantaneous QRS X, Y, and Z amplitudes of the VMCG, respectively, could be explained by the instantaneous X, Y, and Z amplitudes of the VECG.