A comparison between Frank and SVEC III lead systems in normal subjects

The Frank and the SVEC III lead systems were used to record the vectorcardiograms (VCGs) of 10 normal subjects. The VCGs obtained using the two leads were compared. The QRS and the T magnitudes of the Frank lead were 25-30% and 13%, respectively, larger than those of the SVEC III. The maximum QRS vectors of the Frank lead were less inferiorly and less posteriorly oriented. Maximal T vectors of the Frank lead were less inferiorly and less anteriorly oriented. When the VCGs of 318 adult male Minnesotans (Minnesota group) recorded by the SVEC III lead system were compared with the VCGs of 510 adults from Washington, D.C. (Draper group) recorded by the Frank system, the magnitudes of QRS and T of the Draper group were larger. The percent increase of voltage was comparable to that seen when the two leads were compared in the same population. There were angular differences between the Draper and the Minnesota groups which could not be explained by lead differences. The differences were attributed to the differences in populations. It was also noted that there are significant differences in the normal values published by various authors and that the normal values obtained from one population should be applied with caution to other populations.