Independent mapping methods reveal rotational activation near pulmonary veins where atrial fibrillation terminates before pulmonary vein isolation

Abstract

Objective: To investigate mechanisms by which atrial fibrillation (AF) may terminate during ablation near the pulmonary veins before the veins are isolated (PVI).

Introduction: It remains unstudied how AF may terminate during ablation before PVs are isolated, or how patients with PV reconnection can be arrhythmia-free. We studied patients in whom PV antral ablation terminated AF before PVI, using two independent mapping methods.

Methods: We studied patients with AF referred for ablation, in whom biatrial contact basket electrograms were studied by both an activation/phase mapping method and by a second validated mapping method reported not to create false rotational activity.

Results: In 22 patients (age 60.1 ± 10.4, 36% persistent AF), ablation at sites near the PVs terminated AF (77% to sinus rhythm) prior to PVI. AF propagation revealed rotational (n = 20) and focal (n = 2) patterns at sites of termination by mapping method 1 and method 2. Both methods showed organized sites that were spatially concordant (P < 0.001) with similar stability (P < 0.001). Vagal slowing was not observed at sites of AF termination.

Discussion: PV antral regions where ablation terminated AF before PVI exhibited rotational and focal activation by two independent mapping methods. These data provide an alternative mechanism for the success of PVI, and may explain AF termination before PVI or lack of arrhythmias despite PV reconnection. Mapping such sites may enable targeted PV lesion sets and improved freedom from AF.

Keywords: FIRM mapping; atrial fibrillation; catheter ablation; focal activation; rotors.

© 2018 Wiley Periodicals, Inc.

Figures

Figure 1. Termination of AF by prospectively ablating a left pulmonary vein carina rotational site prior to PVI in a 61-year-old male (panel 16 from Figure 3) with persistent AF

(A) Electroanatomic shell showing ablation site (outlined in white, red arrow). (B) Electrograms show acute AF termination during ablation and ongoing PV connection to LA. (C) Still panels from movie 1 (activation/phase mapping) show counterclockwise rotational activation at the termination site. Red-green region is Rotational Activity Profile (RAP), i.e., the automatically identified site of phase singularity clustering (rotational activity). (D) Still panels from movie 2 (method 2) also shows counterclockwise rotational activation at the same site.

Figure 2. Termination of AF by ablating at a LIPV rotational site in a 60-year-old female (panel 19 from Figure 3) with paroxysmal AF

(A) Electroanatomic shell identifying ablation site (outlined in white) leading to AF termination. (B) Electrograms show acute AF termination during ablation and ongoing PV connection to LA. (C) Still panels from activation/phase mapping in movie 3 showing counterclockwise rotational activation at the termination site. Again, red-green region is Rotational Activity Profile (RAP), algorithmically identified area of highest rotation. (D) Still panels from method 2 in movie 3 also show counterclockwise rotational activation at the same site.

Figure 3. Montage of Peri-PV ablation sites that terminated AF prior to PV isolation

Panels indicate electroanatomic (NavX or Carto) shells for all 22 patients with ablation site labeled (by white outline or red arrow).