KEY TEACHING POINTS

•Swallow-induced syncope can rarely be caused by atrial tachyarrhythmia arising from the thoracic veins. We describe the first case of deglutition syncope due to atrial tachycardia arising from the superior vena cava (SVC). Percutaneous catheter-based mapping and ablation can be an effective treatment for the management of swallow-induced atrial tachycardia. •Swallow-induced activation of the vagal input through the cardiac ganglionated plexi, resulting in rapid firing from the vein, is a proposed mechanism for syncope. We provide electroanatomic correlation between findings from the electrophysiology study and the potential role of the aortocaval ganglia on the posteromedial aspect of the SVC in this case. Such electroanatomic correlation is also of value in the treatment of common arrhythmias such as atrial fibrillation, which can be triggered by the activation of the ganglionated plexi of the heart. •Recognition of the phenomenon of “reversal of near-field and far-field signals” to identify the chamber of origin of arrhythmia is described with the aid of electrograms. Use of pacing maneuvers to distinguish complex electrograms recorded in thoracic veins is also described.