VALUE OF EPICARDIAL POTENTIAL MAPS IN LOCALIZING PREEXCITATION SITES FOR RADIOFREQUENCY ABLATION - A SIMULATION STUDY

Using computer simulations, we systematically investigated the limitat ions of an inverse solution that employs the potential distribution on the epicardial surface as an equivalent source model in localizing pr e-excitation sites in Wolff-Parkinson-White syndrome. A model of the h uman ventricular myocardium that features an anatomically accurate geo metry, an intramural rotating anisotropy and a computational implement ation of the excitation process based on electrotonic interactions amo ng cells, was used to simulate body surface potential maps (BSPMs) for 35 pre-excitation sites positioned along the atrioventricular ring. T wo individualized torso models were used to account for variations in torso boundaries. Epicardial potential maps (EPMs) were computed using the L-curve inverse solution. The measure for accuracy of the localiz ation was the distance between a position of the minimum in the invers e EPMs and the actual site of pre-excitation in the ventricular model. When the volume conductor properties and lead positions of the torso were precisely known and the measurement noise was added to the simula ted BSPMs, the minimum in the inverse EPMs was at 12 ms after the onse t on average within 0.65 +/- 0.26 cm of the pre-excitation site. When the standard torso model was used to localize the sites of onset of th e pre-excitation sequence initiated in individualized male and female torso models, the mean distance between the minimum and the pre-excita tion site was 0.67 +/- 0.31 cm for the male torso and 0.82 +/- 0.53 cm for the female torso. The findings of our study indicate that a locat ion of the minimum in EPMs computed using the inverse solution can off er non-invasive means for pre-interventional planning of the ablative treatment.