Characterization of drivers maintaining atrial fibrillation: Correlation with markers of rapidity and organization on spectral analysis

Abstract

Background: Better characterization of drivers in atrial fibrillation (AF) may facilitate their identification.

Objective: The purpose of this study was to demonstrate that certain driver characteristics are associated with greater mechanistic importance in maintaining AF.

Methods: Persistent AF was mapped in patients using the CARTOFINDER system with a 64-pole basket catheter to identify and ablate drivers with rotational or focal activity after pulmonary vein isolation. An ablation response was defined as cycle length (CL) slowing ≥30 ms or AF termination. Driver sites with an ablation response were correlated to sites of fastest CL, highest dominant frequency (DF), and greatest organization (lowest cycle length variability [CLV] and highest regularity index [RI]). Parameters predicting AF termination with driver ablation were evaluated.

Results: All 29 patients had ≥1 driver identified. Forty-four potential drivers were identified. The predefined ablation response occurred with 39 drivers (89%): 23 rotational and 16 focal. During a 30-second recording, each driver occurred 8.7 ± 5.4 times and completed 3.1 ± 0.9 consecutive repetitions per occurrence. Driver sites correlated best with markers of organization, corresponding to the site of lowest CLV (29/39 [74%]) and highest RI (26/39 [67%]). Correlation with sites of fastest CL and highest DF was poor (17/39 and 15/39, respectively) and depended on driver temporal stability. Greater temporal stability (3.4 ± 0.9 vs 2.7 ± 0.6; P = .001) and driver correlation with sites of lowest CLV and highest RI (both P <.001) predicted AF termination with ablation.

Conclusion: Intermittent focal or rotational drivers were identified in all patients. Drivers consistently correlated to organization markers. Greater temporal stability and organization predicted AF termination with driver ablation.

Keywords: Atrial fibrillation; Cycle length; Dominant frequency; Pulmonary vein isolation; Rotors.