Lesion characteristics after atrial fibrillation ablation using pulsed field ablation
M Foti, L Bianchini, V De Sanctis, A Sanzo, M Casula, G Zingarini, R Maggio, L Rossi, F Tundo, A Dello Russo, S Bianchi, S Themistoclakis, S Iacopino, C Tondo, R RordorfAbstract
Background
pulsed-field ablation (PFA) technology offers a non-thermal approach that is potentially more selective and safer than traditional techniques, but the extent of lesions and the unintentional involvement of the left atrial (LA) posterior wall (PW) remains unclear.
Purpose
This study aimed to characterize PFA lesion formation following PVI in real-world atrial fibrillation (AF) patients using high-density (HD) voltage mapping. Moreover, this study explored whether unintentional PW involvement is associated with a higher risk of arrhythmias’ recurrence.
Methods
113 patients were prospectively included and underwent PVI with the PFA Farapulse system with at 14 centers. Protocol-directed PVI was delivered using 2 kV with eight applications per vein with additional applications as needed to achieve PVI at operator’s discretion. After PVI, an HD 3-dimensional (3D) map of the LA was performed with the Rhythmia/Orion system (31%), Carto/Pentaray system (29.2%) or NavX/HD Grid system (39.8%) according to operator's choice. Bipolar voltage color display range was set to <0.5 mV to zones of low-voltage areas as either acute lesion formation or chronic scarring. After mapping the LA was segmented into 7 sectors around the right PVs and 7 sectors around the left PVs to enable structured regional analysis. In order to quantify lesion extension across the PW, we identified 9 predefined sectors divided into 3 segments: upper, intermediate and lower (see figure 1). Unintentional PW involvement was defined as involvement of at least 1 of the PW sectors: PW narrowing was defined when 2 sectors of the same segment and PW closure in case of 3 sectors of the same segment involved. Patients were followed for a median of 280 days to track arrhytmias’ recurrences.
Results
PVI was successfully achieved in all patients, with complete antral isolation in 100% of the cases. The mean ablated area around PVs was 34.3±5 cm2: 10.0±4 cm2 at the anterior portion of the PVs, 9.2±2 cm2 at the posterior site, 4.2±1 cm2 in the superior area, 3.9±1 cm2 in the inferior area and 5.3±2 cm2 at the carina region. Unintentional posterior wall involvement was observed in 63 (55.8%) of the patients, PW narrowing in 31 (27%) and PW closure in 8 (7%) following remapping. During follow-up, 10.4% experienced recurrent AF and 8.1% developed atrial tachycardia or flutter. No significant association was found between PW lesion involvement and arrhythmias’ recurrence.
Conclusion
PVI with the Farapulse system was achieved in all patients resulting in complete antral isolation of the PVs in 100% of the cases. PW involvement is not an infrequent finding at post-ablation high-density 3D mapping but does not engender a higher risk of arrhythmias’ recurrences. Larger prospective studies with longer follow-up periods are needed to further clarify the clinical implications of PW involvement.