Intra-SVC Reentrant Atrial Tachycardia Successfully Treated with a Circular Multielectrode Array Pulsed-Field Ablation Catheter – Case Report

Abstract Background The superior vena cava (SVC) is a well-recognized non–pulmonary vein focus in atrial fibrillation (AF); however, intra-SVC reentrant atrial tachycardia (AT) is extremely rare. Case summary An 83-year-old woman with a history of pulmonary vein (PV) isolation using radiofrequency ablation one year earlier was referred for a second ablation due to recurrent AT. Activation mapping of the AT demonstrated a reentrant circuit involving the left atrial (LA) posterior wall. Because bilateral PVs were reconnected, pulsed-field ablation (PFA) including PV re-isolation and left atrial posterior wall isolation was performed using a circular multielectrode array PFA catheter. The initial PFA application did not terminate the tachycardia, however the arrhythmia transitioned to a different AT. High-resolution mapping revealed a reentrant circuit confined within the SVC sleeves, characterized by transverse reentrant propagation. Entrainment pacing confirmed intra-SVC reentry. Circumferential PFA was delivered to the SVC during sinus rhythm, achieving SVC isolation without sinus node dysfunction or phrenic nerve palsy. Discussion This case demonstrates effective management of intra-SVC reentrant AT using a circular multielectrode PFA catheter. High-resolution mapping identified a rare reentrant circuit confined to the SVC. Owing to its tissue selectivity, PFA enables safe and effective SVC isolation while minimizing the risk of phrenic nerve injury.