Atrial Fibrillation Cycle Length Dynamics During Pulmonary Vein Isolation and Posterior Wall Pulsed Field Ablation

The benefit of additional left atrial posterior wall ablation (LAPWA), beyond pulmonary vein isolation (PVI), in persistent atrial fibrillation (PersAF) treatment remains controversial.

We investigated whether signals recorded with a pentaspline pulsed field ablation (PFA) catheter can identify PersAF patients with rapid LAPW activity who may benefit from LAPWA. We additionally evaluated whether PFA-induced atrial fibrillation cycle length (AF-CL) prolongation predicts arrhythmia-free survival.

In this multicenter observational study, consecutive PersAF patients undergoing first-time PVI plus-LAPWA with a pentaspline PFA catheter were included. 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. Any atrial tachyarrhythmia (ATA) lasting >30 seconds beyond the 2-month blanking period was recorded.

270 patients were included. 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 (HR 1.263, 95% CI: 0.739-2.160; p=0.393). In contrast, a greater CS-CL prolongation was independently associated with lower arrhythmia recurrence risk (HR 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 PersAF patients. CS-CL prolongation >23.5% after LAPWA may serve as a useful real-time marker of effective substrate modification and arrhythmia control.