Arrhythmias in d-Transposition of the great arteries after Mustard- or Senning-type atrial redirection surgery - 22 years of experience in catheter ablation and follow-up.

BACKGROUND: Until the late 1980s dextro-transposition of the great arteries (d-TGA) was primarily treated by Mustard or Senning (M/S) atrial redirection surgery. Common long-term complications in these patients include atrial tachyarrhythmias, yet data on catheter ablation in this population remain limited. OBJECTIVE: To assess procedural characteristics, acute success, and long-term outcomes. METHODS: We retrospectively analyzed all d-TGA patients following M/S surgery who underwent electrophysiologic procedures for atrial tachyarrhythmia at a tertiary referral center between June 2001 and June 2023. RESULTS: Ninety-seven patients (35% female; 50 Mustard) underwent 160 electrophysiological procedures. A total of 111 tachyarrhythmias were identified. Cavotricuspid isthmus (CTI)-dependent macro-reentrant atrial tachycardia was the most common substrate and successfully treated in 90% of procedures. Localized reentrant atrial tachycardia was the second most frequent arrhythmia with an age-dependent increase in relative frequency. Overall, 86% of substrate-guided ablations were acutely successful. In procedures with non-inducible or non-sustained arrhythmias, strategic CTI ablation was performed routinely. During a median follow-up of 6.0 years, 95 tachyarrhythmias occurred, of which 13% represented recurrences of previously ablated arrhythmias. Strategic CTI ablation was not associated with a statistically significant increase in subsequent arrhythmias compared to substrate-guided ablations. Arrhythmias during follow-up were more common after Mustard than Senning surgery (HR 1.87; 95% CI 1.06-3.31; p=0.030). CONCLUSIONS: Catheter ablation in d-TGA patients with M/S surgery is feasible and highly effective, with durable results for targeted arrhythmias. However, the high incidence of de-novo arrhythmias underscores the persistent risk for arrhythmias in this population and highlights the need for adjusted long-term management strategies.