Magnetocardiographic localization of a non-magnetic pacing catheter

The position of a non-magnetic pacing catheter was localized non-invasively from multichannel magnetocardiographic (MCG) measurements in 5 patients. A catheter specially designed to produce no magnetic disturbances was inserted in the heart after standard electrophysiological studies. Its position was recorded on cine X-ray images; thus the catheter was serving as an exactly defined current-dipole source. Magnetocardiograms were then recorded in a magnetically shielded room during cardiac pacing, and the MCG localization was performed using boundary element torso models. The MCG localizations were in good agreement with the catheter positions defined from the X-ray images; the average difference between these locations was 22/spl plusmn/6 mm.