Atrial fibrillation cycle length dynamics during pulmonary vein isolation and posterior wall pulsed field ablation: predictive insights in patients with persistent atrial fibrillation

Pulmonary vein isolation (PVI) alone is often insufficient for catheter ablation (CA) of persistent atrial fibrillation (PerAF), and the benefit of additional left atrial posterior wall ablation (LAPWA) remains controversial.

We investigated whether signals recorded with a pentaspline pulsed field ablation (PFA) catheter can identify PerAF patients with rapid LAPW activity who may benefit from LAPWA. Additionally, we evaluated whether PFA-induced atrial fibrillation cycle length (AF-CL) prolongation, measured from the coronary sinus (CS), predicts arrhythmia-free survival.

In this multicenter observational study, consecutive PerAF patients undergoing first-time ablation with a pentaspline PFA catheter were included. PVI and LAPWA were performed in all cases. AF-CL was measured using the FARS-10 method at three time points: baseline, post-PVI, and post-LAPWA, using distal CS signals. LAPW-CL was measured post-PVI from multiple LAPW positions, with the fastest value retained. Arrhythmic recurrence was defined as any atrial tachyarrhythmia (ATA) lasting >30 seconds beyond the 2-month blanking period.

Among 270 included patients (mean age 67.1 ± 11.0 years; 29.6% female). Median AF duration was 12 [9-20] months. The overall 12-month ATA-free survival was 72.6%. "Fast LAPW activity" was defined as a LAPW-CL value shorter than the mean LAPW-CL of the entire cohort (191.4±2.4 msec; ≤ 190 msec). Fast LAPW activity was not associated with arrhythmia recurrence (OR 1.263, 95% CI: 0.739–2.160; p=0.393). In contrast, a greater CS-CL prolongation following PVI + LAPWA was independently associated with lower recurrence risk (OR for arrhythmia recurrence 0.298, 95% CI: 0.017–0.520; p<0.001). A CS-CL increase >23.5% from baseline had a sensitivity of 0.65 and specificity of 0.72 for predicting ATA-free survival.

Post-PVI fast LAPW activity does not predict recurrence after LAPWA in PerAF patients. However, a CS-CL prolongation >23.5% after LAPWA may serve as a useful real-time marker of effective substrate modification and arrhythmia control