In dextro-transposition of the great arteries post-atrial 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, with failed acute efficacy, severely impaired systemic right ventricular contractility, prolonged PR interval, and multiple inducible ATs identifying patients at highest risk.
Key Findings
Results
Cavotricuspid isthmus-dependent atrial tachycardia was the most common circuit type identified in dextro-transposition of the great arteries patients after atrial switch.
33 patients underwent 46 ablation procedures at a single center between 2003 and 2025
66 atrial tachycardias were induced during index procedures; 51 (83%) were characterized
Of characterized tachycardias, 32 (63%) were cavotricuspid isthmus-dependent
11 (22%) were classified as incisional tachycardias
Arrhythmias were mechanically induced with decremental pacing or extra stimuli
Results
Acute ablation efficacy was high, with cavotricuspid isthmus block achieved in 84% and acute noninducibility in 73% of index procedures.
Cavotricuspid isthmus block was achieved in 84% of applicable cases
Acute noninducibility was achieved in 73% of index procedures
Acute success was defined as elimination of all clinical and reproducibly inducible tachycardias (cycle length >200 ms) with bidirectional cavotricuspid isthmus block when applicable
The procedure was described as safe based on the study's characterization
Results
Long-term recurrence of atrial tachycardia after catheter ablation was substantial, with 45.5% of patients experiencing recurrence over a median follow-up of 7.0 years.
Median follow-up was 7.0 years (interquartile range, 2.5–10.4 years)
15 patients (45.5%) experienced recurrence
1-year freedom from recurrence was 75%
Recurrence was defined as any documented atrial tachycardia lasting >30 seconds
Results
Four variables were significantly associated with atrial tachycardia recurrence: failed or uncertain acute efficacy, severely impaired systemic right ventricular fractional shortening ≤22%, prolonged PR interval (220 ms), and greater number of inducible atrial tachycardias.
All four predictors reached statistical significance (all P<0.05)
In multivariable modelling, these four variables yielded an optimism-corrected C-index of 0.85, indicating strong predictive discrimination
Severely impaired systemic right ventricular fractional shortening was defined as ≤22%
Prolonged PR interval threshold was 220 ms
Results
Redo ablation was performed in 33% of patients and was associated with favorable outcomes, with only 3 of 8 patients who achieved acute noninducibility subsequently recurring.
8 of 11 redo patients achieved acute noninducibility
Only 3 of those 8 recurred after redo ablation
This suggests that repeat ablation may be effective for patients with initial recurrence
What This Means
This research examines outcomes of catheter ablation — a procedure that uses energy delivered through a catheter to destroy abnormal electrical pathways in the heart — in adults who had corrective heart surgery (atrial switch) as children for a congenital condition called dextro-transposition of the great arteries (d-TGA). These patients frequently develop abnormal fast heart rhythms called reentrant atrial tachycardias later in life, which are linked to serious complications. The study followed 33 patients over a median of 7 years after their first ablation procedure, finding that the most common abnormal circuit involved a structure called the cavotricuspid isthmus, though scar-related circuits were also common.
The procedure was acutely successful in most patients — the targeted circuits were eliminated in about 73–84% of cases during the procedure itself. However, over the long term, nearly half of patients (45.5%) experienced a return of their arrhythmia, with 25% recurring within just the first year. Four factors predicted who was most likely to have a recurrence: incomplete success during the initial procedure, severely weakened function of the right ventricle (the heart chamber that pumps blood to the body in these patients), a prolonged electrical conduction time called the PR interval, and having more arrhythmia circuits triggered during testing. Together, these four factors showed strong ability to identify high-risk patients.
This research suggests that while catheter ablation is a safe and effective first-line treatment for these arrhythmias, a significant proportion of patients will need repeat procedures. For those who did undergo a second ablation and achieved complete elimination of inducible rhythms, outcomes were much better. The identified risk factors may help clinicians decide which patients need closer monitoring or earlier referral for repeat ablation, potentially improving long-term care for this complex group of congenital heart disease survivors.
Álvarez-Ortega C, González-Ferrero T, Canales-Muñoz L, González-Estriégana S, Diz-Díaz J, González-García A, et al.. (2026). Long-Term Efficacy of Catheter Ablation for Reentrant Atrial Tachycardia in Dextro-Transposition of the Great Arteries Patients After Atrial Switch.. Circulation. Arrhythmia and electrophysiology. https://doi.org/10.1161/CIRCEP.125.014811