Transient sinus arrest caused by coronary spasm of the sinus node artery after pulsed field ablation for superior vena cava isolation: a case report.

Background: Pulsed field ablation (PFA) has emerged as a novel non-thermal ablation modality with preferential myocardial selectivity. However, its effects on adjacent structures, including the sinus node and its arterial supply, remain incompletely understood. Case summary: A 72-year-old woman underwent repeat ablation for recurrent paroxysmal atrial fibrillation. Following pulmonary vein isolation, superior vena cava (SVC) isolation was performed using a PFA system. Sinus rhythm was initially preserved. However, sinus arrest developed several minutes after ablation. High right atrial backup pacing was initiated. Coronary angiography revealed severe spasm of the sinus node artery. Sinus node function gradually recovered after supportive management. Post-procedural voltage mapping confirmed successful SVC isolation. Discussion: This case highlights delayed sinus arrest following SVC isolation using PFA, with angiographic evidence suggesting sinus node artery spasm. While multiple mechanisms may contribute to sinus node dysfunction after PFA, coronary vasospasm should be considered, particularly in cases with delayed onset.