Posterior Wall Involvement During Pulmonary Vein Isolation Using the Farapulse System.

Background: First approved PFA (Pulsed-Field-Ablation) system for pulmonary vein isolation (PVI) has been Farapulse PFA system. The aim was to assess the characteristics of the lesion made by the Farapulse system and its influence on the clinical results.

Methods: First 76 consecutive patients referred for PVI and treated with the Farapulse PFA system were included. A voltage and an activation map were performed before and after PVI. An imaginary middle line was measured between the two carinas. Fusion on the posterior wall was defined when the contralateral ablation areas were connected. We arbitrarily defined a narrow corridor as one that measured < 20 mm of healthy tissue (voltage > 0.5 mV).

Results: Post-PVI mapping revealed an unexpected narrow corridor in the posterior wall in 12 (15%) and fusion in 18 (23%) patients. The multivariate analysis revealed that the only independent predictor was the length of the middle inter-carinas line. The length of the middle posterior line was significantly shorter in patients with affectation of the posterior wall (62 ± 2 vs. 71 ± 3 mm, p = 0.0001). ROC curve showed that a middle line cutoff value of 65 mm offered a sensitivity and specificity of 80% and 70% (AUC: 0.82; 95% CI: 0.59-0.84). A corridor < 10 mm is associated with slow conduction velocity below 0.7 m/s, but narrow corridor or fusion were not associated with atrial fibrillation recurrences.

Conclusions: 30 (40%) patients showed narrow corridor or fusion on the posterior wall. The only independent predictor was the length of the middle inter-carina line.