Magnetocardiographic functional localization using current multipole models

High-resolution magnetocardiographic (HR-MCG) mapping was applied to localize the ventricular preexcitation site in ten patients suffering from Wolff-Parkinson-White syndrome. Three different source models were tested, consisting of current and magnetic dipole and the current quadrupole moments in a general multipole expansion. Noninvasive localizations were performed by computations based on measured magnetic maps without a priori assumptions of the source location and without imposing any constraints. In all cases, the computed results were compared with invasive localization results obtained by a catheter mapping technique. Preoperative catherization localizes the atrial end of the accessory pathway, while the authors' method localizes the ventricular preexcitation site. Of the models used the average three-dimensional difference between the invasive localization results and the HR-MCG results was smallest for the source model consisting of the magnetic dipole.