Cardioneural and accessory atrioventricular pathway ablation for vagally mediated atrial fibrillation in PRKAG2 syndrome.

Cardioneural ablation (CNA) is an emerging strategy for vagally mediated arrhythmias, but its role in patients with underlying conduction system disease remains undefined. Here, a young patient with PRKAG2-mediated cardiomyopathy presented with refractory paroxysmal atrial fibrillation (AF) despite prior accessory atrioventricular pathway (AP) ablation and antiarrhythmic therapy. Episodes of AF were triggered consistently by cold milk ingestion, and dual-chamber pacemaker interrogation revealed a high atrial pacing burden due to sinus pauses, suggesting a vagally mediated mechanism superimposed on underlying conduction disease. Extracardiac vagal stimulation during electrophysiology study unmasked residual AP conduction and resulted in sinus pause and AV block. These findings confirmed vagal tone as the dominant arrhythmia modulator and prompted repeat AP ablation and CNA. At follow-up, CNA eliminated vagally mediated sinus pauses, reducing atrial and ventricular pacing burden to 0%, with only low-burden asymptomatic AF persisting.