PO-02-128 REDO PROCEDURES AFTER SINUS NODE SPARING HYBRID ABLATION FOR INAPPROPRIATE SINUS TACHYCARDIA / POSTURAL ORTHOSTATIC SINUS TACHYCARDIA

Background: A novel sinus node (SN) sparing hybrid ablation for inappropriate sinus node tachycardia (IST)/Postural Orthostatic Tachycardia Syndrome (POTS) has been demonstrated to be an effective and safe therapeutic option in patients with symptomatic drug-resistant IST/POTS. Objective: The aim of this study was to evaluate the long-term rate of redo procedures after hybrid IST ablation and procedural strategy, outcomes and safety of redo procedures. Methods: All consecutive patients from 2015 to 2023 were prospectively enrolled in the UZ Brussel monocentric IST/POTS registry. They were analyzed if the following inclusion criteria were fulfilled: 1) Diagnosis of IST or POTS; 2) symptomatic IST/POTS refractory or intolerant to drugs; 3) Hybrid SN sparing ablation performed. The primary endpoint was redo procedure. The primary safety endpoint was pacemaker (PM) implantation. If redo procedure was performed for IST, and lines were not blocked (SVC, IVC and crista terminalis or CT line), ablation was performed to block all lines. If line block was already present or not sufficient to reach the acute endpoint, additional applications on the CT were performed. Acute endpoint was a reduction of at least 25% of the heart rate or accelerated junctional rhythm. Results: A total of 220 patients undergone to hybrid IST ablation were included, 185 patients (84.1%) were treated for IST and 61 patients (27.7%) for POTS, Figure. After a follow-up of 73.3 ± 16.2 months, 34 patients (15.4%) underwent a redo. A total of 23 patients (67.6%) had a redo for IST recurrence and 11 patients (32.4%) for other arrhythmias, Figure. In the group of 23 patients (67.6%) with IST recurrence, 19/23 patients had at least one line (SVC, IVC or CT) not blocked and 18/23 patients had a gap in the CT line requiring endocardial ablation, Figure. PM implantation was performed in 21 patients (9.5%). Nine patients (4.1%) had no redo procedure and experienced sick sinus syndrome requiring a PM. Twelve patients (5.4%) received a PM as a shared therapeutic choice combined with SN endocardial ablation procedure. Conclusion: In a large cohort of patients the long-term free survival from redo procedure after hybrid IST ablation was 84.6% with a low PM implantation rate. [Formula presented]