Catheter ablation of arrhythmias in ebstein's anomaly: a multicenter study

In patients with Ebstein's anomaly (EA) arrhythmias are frequently encountered. Although most arrhythmias can be targeted with catheter ablation, specific issues render the procedure more challenging in EA. This study examines the mechanisms of the different arrhythmias related to EA and the outcome after catheter ablation.

Clinical and procedural data of catheter ablation in patients with EA in 4 European centers were analyzed. In 32 patients (mean age 24 ± 15 years), 34 accessory pathways (APs), 8 intra-atrial reentry tachycardias (IART), 5 cavotricuspid isthmus-dependent atrial flutter (CTI-AFL), 2 focal atrial tachycardias, and 1 atrioventricular nodal reentry tachycardia were ablated. In 11 patients (34%), multiple ablation targets were present. Eighteen patients (56%) required multiple procedures either for repeat ablation of the same arrhythmia (n = 12), ablation of a different arrhythmia (n = 4), or both re-ablation of the same and of a different arrhythmia (n = 2). Procedural success rate after first ablation was 80% for APs and CTI-AFL ablation, and 100% for IART ablation. Redo procedures were necessary in 40% of the patients after ablation of an APs, and in 60% after CTI-AFL ablation, but in none of the patient with IART ablation.

Most arrhythmias related to EA are amenable to catheter ablation. However, ablation procedures are challenging and the need for repeat procedure is particularly high, because some patients have multiple ablation targets and because of technical issues in relation with the dysplastic tricuspid annulus. In addition, several patients develop other arrhythmia mechanisms following ablation.