Early Recurrence Predicts Late Recurrence in Pulsed Field Ablation of Atrial Fibrillation Even with Modified Blanking Period: Outcomes from a 1000-Patient Cohort

Background: Early recurrence of atrial tachyarrhythmias (ERAT) after pulmonary vein isolation (PVI) using thermal energy is common, but is not considered a treatment failure within the traditional 90-day blanking period (BP) as the cardiac tissue is still healing and inflammation persists, so that the full benefit of PVI may not yet be apparent. For pulsed-field ablation (PFA), a non-thermal technology, the role of ERAT post-PVI remains unclear.

Methods:  A cohort of 1000 consecutive patients with symptomatic atrial fibrillation (AF) underwent PFA-PVI from April 2021 to April 2024. We analyzed the incidence of ERAT and compared traditional (90-day; ERAT1) and updated (8-week; ERAT2) BPs. Arrhythmia recurrence was defined as AF or atrial tachycardia (AT) episodes lasting over 30 seconds. Patients with repeat procedure in blanking time or with recurrence in blanking that was left untreated were excluded.

Results: In all 100 patients (62.7% male, median age 69 [IQR 60-76] years), complete PVI was achieved using solely PFA. Fifteen Patients were excluded due to a repeat procedure or untreated recurrence during BP.  Median follow-up (FU) was 331 days and ERAT1 occured in 160/985 (16.2%) patients and was more frequent in persAF (persAF=22.1%; PAF=12.0%; p<0.001). Median time to ERAT1 was 9 [3-31] days. At one-year, overall freedom from atrial arrhythmia outside of ERAT1 was 75.1% and was significantly lower for patients with ERAT1 compared to patients without ERAT1 (ERAT1=47.6%; no ERAT1=81.1%, p<0,001). This difference was significant for both, patients with PAF (ERAT1= 50.3%; no ERAT1= 88.1%; p<0.001) and patients with persAF (ERAT1= 45.0%; no ERAT1= 70.1%; p<0.001).  In total, 83/160 (51.9%) of patients with ERAT1 had documented late recurrence (LR), compared to only 152/825 (18.4%) of patients in sinus rhythm throughout BP (p<0.001).

When applying the new 8 weeks BP, patients with early recurrence still had a significantly lower freedom from AF/AT at one year compared to patients with no recurrence (ERAT2=49.8%; no ERAT2= 78.1%; p<0,001) and this difference was significant for PAF (p<0.001) and persAF (p=0.013). Furthermore 68/137 (49.6%) of patients with ERAT2 experienced LR, compared to only 175/848 (20.6%; p<0.001) patients who maintained sinus rhythm throughout BP.

Conclusion: In this large cohort, early recurrence of atrial tachyarrhythmia following PFA PVI was associated with late recurrences in the majority of cases, even when applying the new blanking period and independent of AF type. This leads to the conclusion that the concept of blanking period following non thermal energy ablation for atrial fibrillation should be further questioned.