Clinical Predictors of Recurrent Cavotricuspid Isthmus Flutter After Catheter Ablation in Patients With Dextro‐Transposition of the Great Arteries

INTRODUCTION: Patients with surgically repaired D-transposition of the great arteries (D-TGA) via atrial switch are at high risk of cavotricuspid isthmus (CTI) dependent atrial flutter, which can be challenging to address. High rates of CTI-dependent flutter recurrence after initial ablation have been reported, but clinical predictors of recurrence remain poorly understood. METHODS: We identified patients with a history of d-TGA repaired with atrial switch undergoing catheter ablation for CTI- dependent flutter from 2011 to 2023. Demographics, cardiac imaging, and procedural characteristics were analyzed. Clinical and procedural characteristics were compared between patients with and without recurrence. RESULTS: Of 19 patients who underwent catheter ablation, 9 (47.3%) had recurrent CTI-dependent flutter over a median follow-up of 2.96 (IQR 0.88-5.08) years. Median recurrence time was 1.3 years (IQR 0.33-2.0) years postablation. Moderate or greater dilation of the systemic ventricle (100% vs. 54% p = 0.01) and systemic atrioventricular valve (AV) regurgitation (60% vs. 8% p = 0.01) correlated with recurrence. No differences were noted in need for pulmonary venous access, flutter cycle length, split duration, or transisthmus time. CONCLUSION: Nearly half of patients with repaired d-TGA undergoing index CTI-dependent flutter ablation experience recurrence. Clinical and anatomic factors such as systolic dilation and AV regurgitation in the systemic ventricle were significantly associated with recurrence and provide operators with information on at-risk profiles which may influence postprocedural care and monitoring.