Randomized Trial of Electrographic Flow-Guided Ablation During Redo Procedures for Non-Paroxysmal Atrial Fibrillation (FLOW-AF) (JCEP August 2024)-Article: Randomized Trial of Electrographic Flow-Guided Ablation During Redo Procedures for Non-Paroxysmal Atrial Fibrillation (FLOW-AF)

Article: Randomized Trial of Electrographic Flow-Guided Ablation During Redo Procedures for Non-Paroxysmal Atrial Fibrillation (FLOW-AF)

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The FLOW-AF study was a multicenter randomized controlled trial aimed at evaluating the efficacy of Electrographic Flow (EGF) mapping to identify and ablate extrapulmonary vein sources of atrial fibrillation (AF) in patients with persistent (PerAF) or long-standing persistent atrial fibrillation (LS-PerAF) undergoing redo ablation procedures. Traditional pulmonary vein isolation (PVI) procedures are often insufficient for nonparoxysmal AF patients, prompting the investigation of alternative ablation strategies.<br /><br />In the study, patients were stratified based on EGF mapping results, where 26.5% was set as the threshold for significant source activity. The trial involved 85 patients from four centers, with a 1:1 randomization for those exceeding the threshold to undergo PVI plus EGF-guided ablation versus PVI only. The follow-up included electrocardiographic monitoring at 3, 6, and 12 months.<br /><br />Among participants, 60% had AF sources above the threshold. These patients were older and had higher CHA2DS2-VASc scores, indicating greater stroke risk. The study reported a 95% success rate in ablating identified sources in the EGF-guided ablation group. The primary efficacy outcome showed that 68% of patients in the EGF-guided ablation group were AF-free at 12 months, compared to 17% in the PVI-only group. The primary safety outcome indicated a 97.2% freedom from serious adverse events related to the procedure.<br /><br />The results suggest that EGF mapping can effectively guide the ablation of extrapulmonary vein sources, significantly improving the AF-free survival rates compared to PVI alone. EGF mapping identifies functional mechanisms of AF, offering a more targeted ablation strategy tailored to individual patient pathophysiology, which can enhance clinical outcomes in the challenging redo PerAF/LS-PerAF patient population. Future studies are recommended to confirm these findings in larger cohorts and further refine EGF-based AF phenotyping methodologies.

Keywords

FLOW-AF study

Electrographic Flow mapping

atrial fibrillation

redo ablation

persistent AF

long-standing persistent AF

pulmonary vein isolation

EGF-guided ablation

clinical outcomes

AF-free survival