Background: Electrographic Flow (EGF) mapping enables full spatiotemporal reconstruction of organized wavefront propagation to identify extra-pulmonary vein (PV) sources of atrial fibrillation (AF).

Objectives: FLOW-AF was multicenter, randomized controlled study of EGF mapping to: stratify a non-paroxysmal AF population undergoing redo-ablation, guide ablation of these extra-PV AF sources, and improve AF recurrence outcomes.

Methods: FLOW-AF enrolled persistent (PerAF)/long-standing PerAF patients undergoing redo-ablation at 4 centers. One-minute EGF maps were recorded from standardized bi-atrial basket positions. Patients with source activity >= 26.5% were randomized 1:1 to PVI+EGF-guided ablation versus PVI-only; patients without sources >= 26.5% threshold were not randomized. Follow-up and EKG monitoring occurred at 3-, 6- and 12-months.

Results: We enrolled 85 patients: age 65.6+/-9.3 years; 37% female; 24% long-standing PerAF. Thirty-four (40%) patients had no sources >threshold; at least 1 source >threshold was present in 46 (60%; EGF-guided ablation = 22 / Control = 26). Patients with sources were older (68.2 versus 62.6 years; p=0.005) with higher CHA2DS2-VASc scores (2.8 versus 1.9; p=0.001). The freedom from safety events was 97.2%, and 95% of EGF-identified sources were successfully ablated. In randomized patients, AF-free survival at 12-months was 68% for EGF-guided ablation versus 17% for Control (p = 0.042); freedom from AF/AT/AFL at 12-months was 51% versus 14% (p=0.103), respectively.

Conclusions: In non-paroxysmal AF patients undergoing redo-ablation, EGF mapping identified AF sources in 60% of patients, and could be successfully ablated in 95%. Compared to PVI alone, PVI + source ablation improved AF-free survival by 51% on an absolute basis.

Editor-in-Chief
Kalyanam Shivkumar, MD, PhD, FACC
 
CME Editor
Kenneth A. Ellenbogen, MD, FACC

Author
Mahmoud Houmsse, MD, FACC


Important Dates
Date of Release: August 26, 2024
Term of Approval/Date of CME/MOC Expiration: August 25, 2025