Predictors of Acute Failure Ablation of Intra‐atrial Re‐entrant Tachycardia in Patients With Congenital Heart Disease: Cardiac Disease, Atypical Flutter, and Previous Atrial Fibrillation

Background Intra‐atrial re‐entrant tachycardia ( IART ) in patients with congenital heart disease ( CHD ) increases morbidity and mortality. Radiofrequency catheter ablation has evolved as the first‐line treatment. The aim of this study was to analyze the acute success and to identify predictors of failed IART radiofrequency catheter ablation in CHD . Methods and Results The observational study included all consecutive patients with CHD who underwent a first ablation procedure for IART at a single center from January 2009 to December 2015 (94 patients, 39.4% female, age: 36.55±14.9 years). In the first procedure, 114 IART were ablated (acute success: 74.6%; 1.21±0.41 IART per patient) with an acute success of 74.5%. Cavotricuspid isthmus–related IART was the only arrhythmia in 51%; non–cavotricuspid isthmus–related IART was the only mechanism in 27.7% and 21.3% of the patients had both types of IART . Predictors of acute radiofrequency catheter ablation failure were as follows: nonrelated cavotricuspid isthmus IART (odds ratio 7.3; confidence interval [CI], 1.9–17.9; P =0.04), previous atrial fibrillation (odds ratio 6.1; CI, 1.3–18.4; P =0.02), transposition of great arteries (odds ratio, 4.9; CI, 1.4–17.2; P =0.01) and systemic ventricle dilation (odds ratio 4.8; CI, 1.1–21.7; P =0.04) with an area under the receiver operating characteristic curve of 0.83±0.056 (CI, 0.74–0.93, P =0.001). After a mean follow‐up longer than 3.5 years, 78.3% of the patients were in sinus rhythm (33.1% of the patients required more than 1 radiofrequency catheter ablation procedure). Conclusions Although ablation in CHD is a challenging procedure, acute success of 75% can be achieved in moderate–highly complex CHD patients in a referral center. Predictors of failed ablation are IART different from cavotricuspid isthmus, previous atrial fibrillation, and markers of complex CHD (transposition of great arteries, systemic ventricle dilation).