VALUE OF SIMULATED BODY-SURFACE POTENTIAL MAPS AS TEMPLATES IN LOCALIZING SITES OF ECTOPIC ACTIVATION FOR RADIOFREQUENCY ABLATION

Body surface potential maps recorded during catheter pace mapping can facilitate the localization of the site of origin of ventricular tachy cardia. In this study, we investigated the value of a realistic comput er model of the human ventricular myocardium in generating body surfac e potential maps as templates for identifying sites of ectopic activat ion. Our model features an anatomically accurate geometry and an aniso tropy due to transmural fibre rotation, that were reconstructed with a spatial resolution of 0.5 mm. It simulates the electrotonic interacti ons of cardiac cells by solving a nonlinear parabolic partial differen tial equation, but it behaves as a cellular automaton when the transme mbrane potential exceeds the threshold value. We successfully validate d our model by comparing the simulated activation sequences - describe d by isochronal maps, epicardial potential maps and body surface poten tial maps - with the measured sequences of epicardial and body surface maps reported in the literature. By systematically pacing the left ve ntricular and right ventricular endocardial surfaces in our ventricula r model, we generated a database of 155 QRS-integral maps, which provi des a high-resolution reference frame for localizing distinct endocard ial pacing sites. This database promises to be a useful tool in improv ing the performance of catheter pace mapping used in combination with body surface potential mapping. Overall, the results demonstrate that our computer model of the human ventricular myocardium is well suited for complementing a database of QRS-integral maps obtained during clin ical pace mapping and can help enhance the efficacy of the ablative tr eatment of ventricular arrhythmias.