Catheter Ablation in Pediatric Congenital Heart Disease: A Modern Perspective.

Arrhythmias in pediatric patients with congenital heart disease (CHD) represent a significant cause of morbidity and mortality in these vulnerable children. Unfortunately, to date, there has been no systematic depiction of the arrhythmic substrates and median term clinical outcome measurements in these patients in the more recent era of catheter ablation. In this issue of Circulation: Arrhythmia and Electrophysiology, Houck et al1 present a detailed retrospective 2-institution review of consecutive pediatric patients with CHD who underwent transcatheter ablation from 2007 to 2018, collecting a cohort of 232 patients. Greater than 75% of the patients presented had 2-ventricle substrates or surgical repairs, with Ebstein anomaly being the most common substrate. Accessory pathways were the most common electrophysiological substrate identified, followed by macroreentrant atrial tachycardias. Complete or partial procedural ablation success was achieved in 84% of cases with an adverse event rate of 9.4%. By 3.6 years follow-up, there were recurrent arrhythmias observed in 49% of patients. Importantly, recurrent arrhythmias following initial ablation were found to represent a different or new electrophysiological substrate in 26% of patients who underwent repeat electrophysiology studies. We congratulate the authors on reporting their ablation results such a large group of children with CHD, who for most programs represent a small minority of the total ablation population. There are several noteworthy takeaways. Acute procedural success rates for patients with CHD have remained rather steady in the current area of ablation. Recent data from the Multicenter Pediatric and Congenital EP Quality Initiative registry2 compiled acute procedural success rates across 12 centers with an acute success rate of 84% in patients with CHD. Papagiannis et al3 published a comprehensive retrospective study of over 100 patients with CHD from 16 centers specifically with atrioventricular nodal reentrant tachycardia and showed success rates of ≥82% with long term success of ≥86% at 3.2 years. This is particularly interesting because 22 patients (20%) presented with atypical atrioventricular nodal reentry tachycardia, which is known to have higher rates of procedural failure likely secondary to abnormal anatomy coupled with displaced conduction tissue and challenging access to the slow pathway. Looking at earlier reports from 2004, Hebe et al4 report acute success rates in CHD ablations of 88%. Despite the technological advances made in the field of cardiac ablation over the past 15 years that have demonstrated improvements in procedural success rates for certain patient cohorts, outcomes have not markedly EDITORIAL