Peak frequency analysis distinguishes nearfield from farfield signals during pulmonary vein isolation

Identifying nearfield and farfield signals is critical to mapping and ablating cardiac arrhythmias. This assessment is qualitative, depending on the "sharpness" of pulmonary vein (PV) electrograms. Electrogram peak frequency (PF) analysis is hypothesized to be a quantitative measure of signal proximity.

This study aimed to confirm whether PF defines nearfield vs farfield electrical signals and whether it can be used during ablation to establish PV isolation (PVI).

We created a cohort of 30 patients with atrial fibrillation (AF) undergoing PVI. Left atrial and PV maps of PF were generated before and after PVI. In the first 10 patients with paroxysmal AF (cohort 1), a cutoff value was selected to predict nearfield vs farfield signals. This cutoff was validated in a cohort of 10 patients with paroxysmal AF (cohort 2) and a cohort of 10 patients with persistent AF (cohort 3).

PF was lower in farfield electrograms than nearfield electrograms. A PF cutoff of 300 Hz had a sensitivity of 93.2% (95% confidence interval [CI] 81.3-98.6) in cohort 1, 90.0% (95% CI 76.3-97.2) in cohort 2, and 98.6% (95% CI 90.1-99.7) in cohort 3 for differentiating farfield from nearfield electrograms. The specificity was 100.0% (95% CI 98.2-100.0), and the area under the receiver operator curve was 0.99 (95% CI 0.97-1.00) in all patients.

We confirmed the hypothesis that PF distinguishes nearfield from farfield electrograms. PF analysis improves the recognition of PVI. Mapping and ablation strategies using PF should be pursued to improve ablation outcomes.