Acute safety and efficacy and long-term outcome of pulsed field ablation for persistent atrial fibrillation in patients with dilated left atrium

Abstract Background Increased left atrial (LA) size in atrial fibrillation (AF) is associated with AF recurrence following ablation. Limited data exist on pulsed-field ablation (PFA) in patients with persistent atrial fibrillation and dilated LA. Purpose We aimed to analyze the efficacy and safety of PFA in patients with severe LA dilatation (SLAD) (≥50 ml/m2) compared to normal to moderate LA dilatation (NMLAD) (<50 ml/m2) and persistent AF. Methods All consecutive patients undergoing AF ablation with the Farapulse system at 14 centers with complete information of left atrial volume index (LAVi) were included. Protocol-directed PVI was delivered using 2 kV with eight applications per vein. Additional lesions were performed at the operator’s discretion. Results 197 patients with a history of persistent AF and were included in the analysis. Of these, 74 (37.6%) had long-standing persistent AF, 47 (23.9%) were female, the mean age was 65±8 years and the mean LVEF was 54±9%. The mean LAVi was 42.8±14 ml/m2, 51 (25.9%) patients showed SLAD. A 3D mapping system was used in 70 (35.5%) of the cases, a more extensive lesion set than PVI was performed in 157 (79.7%) of cases. Patients with SLAD exhibited a lower LVEF (50±10% vs 56±8%, p=0.0001) and had a higher burden of comorbidities (structural heart disease: 23.5% vs 9.6%, p=0.016; coronary artery disease: 31.4% vs 12.3%, p=0.004; chronic kidney disease: 9.8% vs 2.1%, p=0.028). No differences between groups were found in terms of underlying AF type (long-standing AF: 37.3% vs 37.7%, p=1.00), more extensive lesion set than PVI only (82.4% vs 78.8%, p=0.688) and the use of 3D mapping system (43.1% vs 32.9%, p=0.234). No differences were also found between groups in terms of PFA deliveries outside PVs (19[14-26] vs 18[14-22], p=0.324) or total number of PFA deliveries (52[46-66] vs 49[44-57], p=0.0616), whereas skin-to-skin time (84[61-95] min vs 70[55-85] min, p=0.004) and fluoroscopy time was longer (23[15-31] min vs 17[14-23] min, p=0.001) in patients with SLAD. PVI was achieved in all patients. During a median follow-up of 358[196-402] days, 34 (17.3%) of patients experienced an arrhythmic recurrence after the 90-day blanking period. The proportion of patient with SLAD who experienced a recurrence was similar to the ones with NMLAD (15.7% for SLAD vs 17.8% for NMLAD, p=0.831); increased LA size (continuous LAVi values or LAVi ≥ 50 ml/m2) was not associated to recurrences (hazard ratio=1.09, 95%CI: 0.98 to 1.03, p=0.945 for continuous LAVi values; 0.82, 0.34 to 1.79, p=0.612 for LAVi ≥ 50 ml/m2). No major complications occurred in both groups. Conclusion In our experience, the use of Farapulse PFA system for persistent AF ablation in patients with severe LA dilatation demonstrated safe and effective outcomes, mirroring a comparable pattern observed in patient with normal to moderate LA size.