Abstract
We carried out a 3-D MCG vector measurement of the PR segment using a 3-D second-order gradiometer connected to 39 dc-SQUIDs, which can detect the magnetic field components perpendicular to the chest (Bz) and tangential to the chest (Bx, By). The MCG waveform showed a ramp pattern and bump pattern with a positive or negative slope for 40 ms before onset of the QRS wave, which corresponds to excitation of the His-Purkinje conduction system (HPS). The isofield contour maps of Bz showed a dipole pattern, and the isofield contour maps of Bx and By showed one extreme pattern. The source localization was done by a single equivalent current dipole (ECD) method for this time interval. It was shown that calculated ECD traced the HPS activation pathway.
