Catheter ablation for atrioventricular nodal reentrant tachycardia in patients with congenital heart disease

BACKGROUND Variability in atrioventricular (AV) node location in congenital heart disease (CHD) can make catheter ablation for atrioventricular nodal reentrant tachycardia (AVNRT) challenging. OBJECTIVE The purpose of this study was to describe institutional technique and outcomes for slow pathway modification in a cohort with CHD. METHODS The study consisted of a retrospective review of CHD patients who underwent study from 2001 to 2013 with a diagnosis of AVNRT. Outcomes for slow pathway modification were recorded. In cases in which ablation was deferred, the reasons for this choice were examined. RESULTS Forty-nine patients (median age 19 years) were included. CHD anatomy involved D-transposition of the great arteries (n = 6), "congenitally corrected" transposition of the great arteries (n = 4), Ebstein anomaly (n = 4), tetralogy of Fallot (n = 5), venous anomalies (n = 8), single ventricle (n = 16), and miscellaneous (n = 6). Ablation was attempted in 39 patients, using radiofrequency energy in 24, cryoablation in 8, and both in 7. Acute success rate was 92% (36/39). One patient had first-degree block in response to cryoablation, but no other complications occurred. At median follow-up 32 months, 1 patient had AVNRT recurrence. Most of the 10 patients in whom ablation was deferred had single-ventricle anatomy with uncertain AV node location. CONCLUSION Ablation for AVNRT in CHD can be accomplished successfully with attention to underlying anatomy and prior surgery. Patients with single ventricle are a difficult subgroup, and a pharmacologic approach may be indicated in some cases if node localization is ambiguous.