Pulsed-field ablation for redo procedures after failed radiofrequency or cryo ablation for atrial fibrillation

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Pulsed-field ablation (PFA) has recently been introduced for pulmonary vein isolation (PVI). It might also be of potential value for redo procedures after failed radiofrequency or cryo ablation for atrial fibrillation (AF). PURPOSE: To describe our initial experience using a multipolar PFA catheter for redo procedures after failed AF ablation. METHODS: Consecutive patients undergoing a redo procedure for recurrent atrial arrhythmias at our institution using a multipolar PFA catheter from Mai 2021 until October 2022 were included. A 3D electro-anatomical bipolar voltage map was generated to identify pulmonary vein (PV) reconnection, quantify the level of isolation (antral vs. ostial isolation), and characterize the extent of extra-PV low-voltage tissue. In case of PV reconnection, re-isolation was performed using PFA, with at least four applications in both basket and flower configuration. In case of only ostial PV isolation, additional PFA applications in flower configuration were delivered to widen the isolation to a more antral level. If all veins were already isolated on an antral level and/or if low-voltage areas were found on the posterior wall, a posterior wall ablation was added with the same PFA device at the discretion of the operator. RESULTS: We identified 170 patients (mean age: 64 ±11years, 45 (27%) women), undergoing a redo procedure using PFA. The median number of previous ablations was 1 (range 1-6), the most recent ablation was performed using radiofrequency in 122 (72%), cryo in 42 (25%), and surgery in 5 (3%) patients. In 104 (61%) patients, at least one reconnected PV was found. In total, 244 of 680 PV (36%) showed reconnection. In addition to PV reisolation, additional antral applications were delivered in 205 of 436 still isolated veins (47%). Posterior wall ablation was added in 112 (66%) patients (43% in paroxysmal AF, 78% in persistent AF, Figure). Median procedure duration was 101 minutes (IQR 80-137). There was no cardiac tamponade, no stroke, and no esophageal fistula observed in this cohort. CONCLUSION: For patients with recurrence after catheter ablation of atrial fibrillation, re-ablation using PFA is feasible and safe. Most common ablation targets were the pulmonary veins and the posterior wall. Whether the complementary effect of a different technology improves outcome needs further investigation. [Figure: see text]