Single-dipole and dual-dipole inverse solutions in electrocardiography

In this study, we closely examined the performance of inverse solution in terms of equivalent dipole source model. To simulate potential distribution on the body surface, we employed an analytical model of a single current dipole (or a pair of current dipoles) placed within the homogeneous isotropic volume conductor consisting of two non-concentric spheres. Using these data, we evaluated the accuracy of recovering both location and orientation of the single or dual dipole sources. In total, we examined 24 different dipole locations and found that the location of fitted single and dual current dipoles virtually coincided with the original source for high S/N ratios. We extended investigation to more complex geometry, where a computer model of the human ventricular myocardium was used to simulate activation sequences initiated at eight sites positioned on the epicardial surface of the atrio-ventricular ring. From these sequences, 117-lead body surface potentials were simulated on a realistic torso surface and were then used to localize single and dual accessory pathways employing single or dual equivalent dipoles. Average localization errors were 5 and 12 mm for the single and the dual accessory pathways, respectively, what could be useful additional information prior to electrophysiological study.