Regional conduction velocities determined by noninvasive mapping are associated with arrhythmia-free survival after atrial fibrillation ablation.

Background: Atrial arrhythmogenic substrate is a key determinant of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI), and reduced conduction velocities have been linked to adverse outcome. However, a noninvasive method to assess such electrophysiologic substrate is not available to date.
Objective: This study aimed to noninvasively assess regional conduction velocities and their association with arrhythmia-free survival after PVI.
Methods: A consecutive 52 patients scheduled for AF ablation (PVI only) and 19 healthy controls were prospectively included and received electrocardiographic imaging (ECGi) to noninvasively determine regional atrial conduction velocities in sinus rhythm. A novel ECGi technology obviating the need of additional computed tomography or cardiac magnetic resonance imaging was applied and validated by invasive mapping.
Results: Mean ECGi-determined atrial conduction velocities were significantly lower in AF patients than in healthy controls (1.45 ± 0.15 m/s vs 1.64 ± 0.15 m/s; P < .0001). Differences were particularly pronounced in a regional analysis considering only the segment with the lowest average conduction velocity in each patient (0.8 ± 0.22 m/s vs 1.08 ± 0.26 m/s; P < .0001). This average conduction velocity of the "slowest" segment was independently associated with arrhythmia recurrence and better discriminated between PVI responders and nonresponders than previously proposed predictors, including left atrial size and late gadolinium enhancement (magnetic resonance imaging). Patients without slow-conduction areas (mean conduction velocity <0.78 m/s) showed significantly higher 12-month arrhythmia-free survival than those with 1 or more slow-conduction areas (88.9% vs 48.0%; P = .002).
Conclusion: This is the first study to investigate regional atrial conduction velocities noninvasively. The absence of ECGi-determined slow-conduction areas well discriminates PVI responders from nonresponders. Such noninvasive assessment of electrical arrhythmogenic substrate may guide treatment strategies and be a step toward personalized AF therapy.
Competing Interests: Disclosures Dr Till Althoff has received research grants for investigator-initiated trials from Biosense Webster and honoraria as consultant from Corify Care. Prof Lluís Mont has received honoraria as a lecturer and consultant and has received research grants from Abbott Medical, Biosense Webster, Boston Scientific, and Medtronic; he is a shareholder of Galgo Medical SL and Corify Care. Drs Andreu Climent and María S. Guillem are co-founders of Corify Care and receive honoraria from the company. Dr Ismael Hernández is co-founder of Corify Care. Jana Reventos is employed by Corify Care. Drs Ivo Roca-Luque, Jose M. Tolosana, and Andreu Porta-Sanchez received honoraria as consultants for Biosense Webster, Boston Scientific, and Medtronic. Dr Jean-Baptiste Guichard reports honoraria as a consultant from Microport CRM and as lecturer from Microport CRM and Abbott and an unrestricted grant support for a fellowship from Abbott Laboratories.
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