Short and midterm outcome of intraprocedural sinus node dysfunction requiring stimulation during ablation of persistent atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background Ablation within the superior, antero-lateral portions of the right atrium has been described as a risk for sinus node dysfunction (SND) because of direct damage to the sinus node. The sinoatrial nodal artery arises from the right coronary artery in the majority of people and courses close to the superior posterior aspect of the interatrial septum. Rare cases of SND were observed periprocedurally during atrial fibrillation/flutter ablation. We sought to report on clinical characteristics, ablation set and acute and midterm rhythm outcome of patients who develop acute SND during/immediately after exclusively left atrial ablation. Methods We performed a retrospective analysis of AF/Aflutter ablation patients between January 2017 and December 2019 to characterize those who required temporary pacemaker (TPM) implantation due to acute sinus node dysfunction (sinus arrest, sinus bradycardia <35 beats/min with hemodynamic compromise) following atrial ablation. Results Of 1,072 patients, at nine patients [0,8%] intraprocedural temporary pacemaker implantation was necessary due to severe SND and hemodynamic compromise. The reasons for implantation were identified as sinus arrest (n=6) or severe sinus bradycardia (n=3). Eight of nine patients were male [89%], age 73 +11.2, 6/9 [67%] persistent AF, 2/9 [22%] Aflutter. The ablation set consisted of: pulmonary vein (PV) isolation in all patient (n = 9), left atrium(LA)-substrate modification in 8. In detail: roof line ablation (n = 3), mitral annulus-right superior PV line ablation ( n=8), mitral annulus-left superior PV line (n = 3). No patient had an ablation within the the right atrium. Four of nine [22%] pts. received permanent PM before discharge, performed 5 days postablation (range 3-7 days). At 3-month device interrogation, all patients were atrially paced, with a pacing proportion of >40% in 3/4 [0,3%] patients. Conclusion Acute sinus node dysfunction is a rare complication of sole left atrial ablation outside the pulmonary veins. However, a relevant fraction of these patients requires permanent implantation with substantial pacing proportion during midterm follow up.