Spanish Registry of Redo Procedures Following Pulmonary Vein Ablation by Pulsed Field Ablation Technology: RESET-PFA

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical practice in the Western world, significantly impacting patient morbidity and mortality. Catheter ablation, specifically pulmonary vein isolation, has become the treatment of choice for rhythm control in patients with drug-refractory AF. Historically, thermal therapies such as radiofrequency (RF) and cryoablation have been used for pulmonary vein isolation. However, numerous studies have shown that a portion of AF recurrences pulmonary vein ablation can be attributed to pulmonary vein reconnections, suggesting suboptimal lesion durability. Pulsed field ablation (PFA), a novel non-thermal ablation technique using high-voltage, short-duration electrical pulses, has emerged as a promising alternative. PFA induces myocardial cell death via irreversible electroporation, achieving pulmonary vein isolation. Initial clinical trials demonstrated PFA's efficacy, efficiency, and safety, with favorable rates of durable pulmonary vein isolation at 3 months post-ablation.

Following commercialization and widespread adoption, multicenter registries have further confirmed PFA's efficacy and safety. Comparative studies have suggested superior long-term pulmonary vein isolation rates with PFA compared to conventional thermal therapies. Consequently, PFA has the potential to improve lesion durability and clinical outcomes for AF patients. While several studies have investigated pulmonary vein isolation durability in redo procedures in patients with clinical recurrences after PFA, results have been variable (isolation durability range: 63% - 71%), and more data is needed to fully understand the patterns of reconnection.

To our knowledge, all previous studies primarily focused on PFA during the technology's early stages and operator learning curves, potentially biasing results towards suboptimal isolation rates due to inexperience. Additionally, most studies were retrospective and single-center, with only one multicenter registry involving seven hospitals. Furthermore, none of these studies have analyzed the workflow of the index pulmonary vein isolation procedure to explain variations in lesion durability.

Therefore, the investigators present a multicenter, national, retrospective/prospective study of experienced operators to evaluate pulmonary vein isolation durability in patients with AF recurrences after PFA, focusing on the association between index procedure workflow and lesion durability.

The previous considerations seem to suggest the need to conduct a large multicentric registry of experienced operators aimed at observing current clinical practice. The registry should allow the analysis of clinical practice in relation to the current procedural recommendations, the observation of the type of methods and ablation workflow adopted and the reasons for the choices. The long-term follow-up of the patients would allow the estimation of the incidence of arrhythmic occurrences and the evaluation of the outcome, according to the clinical characteristics, the ablative strategy of the index procedure and the validation criteria at the end of the procedure. Furthermore, the prospective observation of a large number of patients treated in clinical practice approached with different ablation approaches would allow to evaluate lesion durability and residual pulmonary vein gaps that have a decisive weight in evaluating the real effectiveness of the therapy and the consequent ablation strategy during repeated ablation. These data could be extremely useful and could guide EPs in choosing the best treatment options.