Electrographic Flow Mapping for Persistent Atrial Fibrillation: Theoretical Basis and Preliminary Observations

Abstract

Ablation strategies remain poorly defined for persistent atrial fibrillation (AF) patients with recurrence despite intact pulmonary vein isolation (PVI). As the ability to perform durable PVI improves, the need for advanced mapping to identify extra-PV sources of AF becomes increasingly evident. Multiple mapping technologies attempt to localize these self-sustained triggers and/or drivers responsible for initiating and/or maintaining AF; however, current approaches suffer from technical limitations. Electrographic flow (EGF) mapping is a novel mapping method based on well-established principles of optical flow and fluid dynamics. It enables the full spatiotemporal reconstruction of organized wavefront propagation within the otherwise chaotic and disorganized electrical conduction of AF. Given the novelty of EGF mapping and relative unfamiliarity of most clinical electrophysiologists with the mathematical principles powering the EGF algorithm, this paper provides an in-depth explanation of the technical/mathematical foundations of EGF mapping and demonstrates clinical applications of EGF mapping data and analyses.

Electrographic flow–guided ablation in redo patients with persistent atrial fibrillation (FLOW-AF): design and rationale

“…Further information regarding the signal processing and the proprietary algorithm are detailed in a previously published white paper. 16 EGF mapping essentially displays the dominant patterns of the AF excitation wave propagation and measures their consistency over time. 20 Starting with a 64-electrode basket catheter, unipolar EGMs are recorded and processed.…”

“…consecutive 19 ms frames of data for each 2-second segment. 16 The identification of statistical singularities are called sources and active sources are defined by divergent wavefront propagation emanating from a singularity of flow vectors. Passive rotations do not generate flow and exhibit convergent flow fields.…”

“…Electrographic flow (EGF) mapping is an innovative technology that uses well-established principles of optical flow and fluid dynamics on a machine learning platform to visualize in vivo, near real-time atrial electrical activation and can identify active sources of excitation and distinguish them from passive rotational activity that do not generate action potentials. 15,16 EGF mapping can detect extrapulmonary vein (extra-PV) sources of AF throughout the right atrium (RA) and left atrium (LA), with most EGF-identified sources representing anatomically feasible targets for ablation. 17 Furthermore, a first-in-human case report recently demonstrated interprocedural EGF map reproducibility showing spatiotemporal stability of EGF-identified sources in the same patient during 2 separate procedures performed 18 months apart.…”