Insights into level of pulmonary vein isolation using pulsed-field ablation for atrial fibrillation and unexpected effects in the posterior wall

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Pulse field ablation (PFA) has emerged as an effective, safe and efficient tool for pulmonary vein isolation (PVI). Purpose We studied the extent of PVI, specifically the isolation of PV antrum, carina and left atria’s posterior wall after PFA with an ultrahigh density mapping (UHD). Methods We involved the first patients referred for atrial fibrillation (AF) ablation treated with a PFA multispline catheter. PFA-lesion extension was assessed with a voltage-map UHD mapping performed before and immediately after PVI. Results Sixty-one consecutive patients underwent PVI with PFA (62±10 year old, 23 women, 39 paroxysmal AF). Four out of 61 patients were excluded because their posterior wall was isolated with extra aplications on purpose. Acute results involved a 100% success of PVI and the only safety issue was a pericardial effusion in one patient managed conservatively. Mean procedure and fluoroscopy times were 59±39 min and 16±5 min, respectively. UHD immediately after PVI revealed early reconnection just in one vein (1/228 veins). PFA created wide antral circumferential lesions without electrical activity registered by UHD mapping inside the isolation area. There were no notch-like normal voltage areas at the anterior or posterior side of carinas. As a result of the PVI with this technology, it was observed the existence of a narrow corridor in the posterior wall in 8 patients (14%) and in another 8 cases right and left antral ablation converged at the posterior wall creating an unexpected isolation area. There was a significant relationship between LA posterior inter-carina distance and posterior wall´s level of isolation (77,1±7mm, no affectation; 68,8±7mm narrow corridor; 60,3±1mm posterior wall isolation (fig 1); p=0.036). Finally, it was a significant linear correlation between posterior inter-carina distance and the distance between the ipsilateral, antral levels of isolation at the posterior wall (fig 2, r=0.79, p=0.001) Conclusion(s) PFA creates wide antral circumferential PVI lesions involving the ipsilateral veins carina. Nevertheless, in small left atria it can create an undesired isolation or a narrow corridor in the posterior wall.