IIntroduction: Atrial fibrillation (AF) ablation requires a precise reconstruction of the left atrium (LA) and pulmonary veins (PV). Model-based FAM (m-FAM) is a novel module recently developed for the CARTO system which applies machine-learning techniques to LA reconstruction. We aimed to evaluate the feasibility and safety of a m-FAM guided AF ablation as well as the accuracy of LA reconstruction using the cardiac computed tomography angiography (CTA) of the same patient LA as gold standard, in 32 patients referred for AF ablation. Methods: Consecutive patients undergoing AF ablation. The m-FAM reconstruction was performed with the ablation catheter (Group 1) or a Pentaray catheter (Group 2). The reconstruction accuracy was confirmed prior to the ablation by verification of pre-specified landmarks of the LA and PVs by intracardiac echocardiogram (ICE) visualization and fluoroscopy. A cardiac CTA performed before the ablation was used as gold standard of LA anatomy. For each patient, the m-FAM reconstruction was compared to his/her cardiac CTA. Results: The m-FAM reconstruction was accurate in all patients regardless the catheter used for mapping. In 12% re acquisition of the LA landmarks was necessary to improve the accuracy. m-FAM time was shorter in group 2 while the M-Fam fluoroscopy time was similar. Pulmonary vein isolation was achieved in 100% of patients without major complications. The m-FAM reconstructions accurately resemble the cardiac CTA of the same patients. Conclusions: The m-FAM module allows for rapid and precise reconstruction of the LA and PV anatomy, which can be safely used to guide AF ablation.

Background. Pulmonary veins (PV) reconnection is the most common reason for atrial fibrillation (AF) recurrence. The ablation-index is a marker of ablation lesion quality which use achieves high percentages of first pass isolation and improved results of AF ablation. Most operators use a double trans-septal approach with confirmation of PV isolation with a circular mapping catheter. In the present study we aimed to show that an ablation-index guided procedure using a single trans-septal approach and ablation catheter only would achieve adequate PV isolation while demonstrating the critical role of the carina in PV isolation. Methods. 76 consecutive patients with paroxysmal AF: 34 patients underwent WACA, 32 patients underwent WACA+ (including empiric carina isolation) and 10 patients underwent a staged procedure of WACA followed by WACA+ in case of lack of first pass isolation. All procedures were performed via single trans-septal. Results. Compared to WACA-only, WACA+ increased the odds of PV isolation from 65% to 91%, p=0.012. In WACA-only, ablation of the carina was needed to achieve PV isolation. The role of the carina was confirmed in 10 patients with sequential ablation. PV isolation was confirmed by inserting a circular mapping catheter through the single trans-septal sheath. At 18 months of follow-up [IQR 15.2-20.8 months], freedom from AF was 84% for the entire cohort. Conclusion. Our study confirms the high success rate of PV isolation using ablation index and shows that this can be achieved via single trans-septal crossing. Our study confirms the role of the carina in PV isolation.