Vivek Y. Reddy, MD; Steven Castellano, PhD; Petr Neuzil, MD, PhD; Melissa Kong, MD
ABSTRACT
Background
Electrographic Flow (EGF) mapping provides a visualization and characterization of wavefront propagation in AF. Based on the presence or absence of EGF-identified extra-pulmonary vein sources of AF, as well as the magnitude of flow vectors through the substrate or electrographic flow consistency (EGFC), patients can be phenotyped. Type I patients have no sources + high EGFC; Type II have sources + high EGFC; Type III have sources+ low EGFC; Type IV have no sources + low EGFC. The presence of EGF-identified sources and low EGFC have previously been associated with higher post-ablation recurrence rates.
Objective
Determine the reproducibility of EGF-based phenotyping pre-PVI and at 3-month remap, as well as the relationship of phenotypes to 1-year outcomes.
Methods
We examined patients with persistent AF and no prior history of AF ablation, who were enrolled in the FLOW-AF randomized controlled trial (NCT04473963) and underwent biatrial EGF mapping followed by PVI. All returned after 3 months for repeat biatrial mapping and PVI touch-up, if indicated. Patients of Type II and Type III were then each randomized 1:1 to EGF-guided source ablation v. PVI-only. Type I and Type IV patients received PVI but no source ablation.
Results
A total of 14 patients with mean age 63±10 years, 36% female, and mean left atrial dimension 4.4±0.5 cm were included in this analysis. Upon initial mapping, 6 patients had high EGFC and 8 had low EGFC. Among all 14 (100%) patients EGFC status remained the same when the patients returned for remapping after a mean of 103±22 days. 11 patients had sources and 3 had no sources on their pre-PVI maps, but 2/11 and 1/3 changed source status 3 -months post-PVI. Pre-PVI phenotype remained the same post-PVI for 79% (11/14). All recurrences occurred in patients with sources; 2 treated Type III and 1 Type II and 1 Type III, both left untreated due to randomization to control.
Conclusions
Pre-PVI EGF phenotyping largely predicts post-PVI phenotypes. Customizing AF ablation strategies based on EGF phenotyping may improve outcomes.
