Electrographic flow-guided ablation was associated with improvement in freedom from atrial fibrillation at 1 year compared with standard pulmonary vein isolation in patients with nonparoxysmal AF requiring a redo ablation, data showed.
The trial included patients with persistent or long-standing persistent AF who required a redo catheter ablation, Vivek Y. Reddy, MD, director of cardiac arrhythmia services for The Mount Sinai Hospital and The Mount Sinai Health System, and the Leona M. and Harry B. Helmsley Charitable Trust Professor of Medicine in Cardiac Electrophysiology at the Icahn School of Medicine at Mount Sinai, said during a presentation at the AF Symposium.
Patients were randomly assigned pulmonary vein isolation alone or pulmonary vein isolation plus electrographic flow (EGF)-guided mapping and ablation using a software system (Ablamap, Ablacon).
“Pulmonary vein isolation is sufficient to treat some patients with AF, but certainly not all,” Reddy said during the presentation. “Ideally we need to be able to identify the other sources that sustain persistent atrial fibrillation. It is particularly important in redo procedures, where the pulmonary veins are already isolated. EGF mapping enables full spatiotemporal reconstruction of the atrial electrical wavefront propagation to identify active AF sources. EGF mapping can detect these extra-pulmonary vein sources of AF by organizing these chaotic electrograms and in retrospective analyses, identification of these sources predicts recurrence, while ablation of these sources predicts clinical success.”
For the FLOW-AF trial, all patients had persistent or long-standing persistent AF and symptomatic, recurrent AF after at least one left atrial ablation procedure. The researchers enrolled 85 patients from four European centers, of whom 46 had at least one clinically relevant extra-pulmonary vein source of AF detected (mean age, 68 years; 39% women) and thus underwent randomization.
Among those randomly assigned to EGF-guided mapping and ablation, 95% had confirmation of successful elimination of their AF source after their procedure. Among the trial population as a whole, 97.2% had freedom from serious adverse events at 7 days, Reddy said.
At 1 year, compared with the control group, the EGF-guided mapping group had a 51% improvement in freedom from AF on an absolute basis (HR = 2.7; 95% CI, 1.1-6.4; P = .04), which was a statistically significant difference despite the trial not being powered to determine that, Reddy said during the presentation.
The EGF-guided mapping/ablation group was also more likely to be free from AF/atrial tachycardia/atrial flutter at 1 year compared with the control group (HR = 2.1; 95% CI, 0.95-4.7; P = .1), he said.
“EGF source ablation does not significantly increase other arrhythmias,” Reddy said during the presentation. “That is an important point. The source ablation is effective in an otherwise difficult-to-treat redo population. A multinational, randomized controlled pivotal trial on whether or not EGF ablation improves outcomes will be conducted at more centers with more operators.”