Magnetocardiographic localization of arrhythmogenic sources

Closed-chest catheter ablation would require precise, non invasive threedimensional <3D) localization of the arrhythmogenic structures. The localiza- tion of His and Kent bundles has been attempted in our laboratory by means of Magnetocardiography (MCG). The accuracy of this method has been tested by comparison with conventional endocardial catheter mapping and by a new developed MCG "pace-mapping" technique. MCB 3D localization is achieved by solving the inverse problem in terms of both equivalent electric <ECD) and magnetic (MCD) current dipoles. So far, 15 patients had simultaneous MCG and invasive electrophysiological investigations. In 5 of them MCG mapping was repeated under cardiac pacing. In all patients the 3D localization of either His or Kent bundle,as well as pacing electrodes was wel1 in agreement with the anatomical position of the sources, although errors in the order of about 1.5 cm. could be observed. The accuracy of the method could be improved using a multisensor device.