Long-Term Efficacy of Catheter Ablation for Reentrant Atrial Tachycardia in Dextro-Transposition of the Great Arteries Patients After Atrial Switch

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BACKGROUND: Reentrant atrial tachycardias (ATs) are frequent after atrial switch for dextro-transposition of the great arteries and are associated with adverse prognosis. Catheter ablation is first-line therapy, yet long-term outcomes and predictors of recurrence remain poorly defined. Our aim was to characterize induced AT circuits, describe acute and long-term catheter ablation outcomes, and identify recurrence predictors in dextro-transposition of the great arteries. METHODS: Single-center ambispective cohort of consecutive adults with dextro-transposition of the great arteries undergoing a first AT ablation (2003–2025). Arrhythmias were mechanically induced with decremental pacing or extra stimuli. Acute success was defined as elimination of all clinical and reproducibly inducible tachycardias (cycle length >200 ms), with bidirectional cavotricuspid isthmus block when applicable. Recurrence was defined as any documented AT >30 seconds. RESULTS: Thirty-three patients underwent 46 procedures. During the index procedure, 66 ATs were induced; 51 (83%) were characterized: 32 (63%) were cavotricuspid isthmus-dependent and 11 (22%) incisional. Cavotricuspid isthmus block was achieved in 84%; acute noninducibility in 73%. Median follow-up was 7.0 years (interquartile range, 2.5–10.4). Overall, 15 patients (45.5%) recurred; 1-year freedom was 75%. Recurrence was strongly associated with failed or uncertain acute efficacy, severely impaired systemic right ventricular fractional shortening ≤22%, prolonged PR interval (220 ms), and greater number of inducible ATs (all P <0.05). In multivariable modelling, these 4 variables yielded an optimism-corrected C-index of 0.85. Eleven (33%) underwent redo ablation; 8 achieved acute noninducibility, and only 3 recurred thereafter. CONCLUSIONS: In dextro-transposition of the great arteries postatrial switch, cavotricuspid isthmus-dependent flutter is most common, but scar-related circuits are frequent. Catheter ablation is safe and acutely effective, but long-term recurrence remains substantial. Failed acute efficacy, severely impaired systemic right ventricle contractility, prolonged PR interval, and multiple inducible ATs identify patients at highest risk and may guide follow-up and referral for early repeat ablation.

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