The Pediatric Radiofrequency Ablation Registry's Experience with Ebstein's Anomaly

Abstract

Radiofrequency Ablation in Pediatric Ebstein's Anomaly. Introduction: Abnormal anatomy and complex electrophysiology in patients with Ebstein's anomaly of the tricuspid valve may confound attempts at radiofrequency ablation (RFA). Methods and Results: Data for 65 pediatric Ebstein's patients (9.8 ± 5.4 years, 4 months to 20 years; 39 ± 25 kg, 5.1 to 108 kg) were obtained from the Pediatric Radiofrequency Ablation Registry. The degree of tricuspid regurgitation (DOTR) and the degree of Ebstein's anomaly were assessed with echocardiography/Doppler. Leading indications were drug refractoriness (24 [37%] of 65 patients) and life‐threatening arrhythmia (14 [22%] of 65 patients). For the 65 patients, 82 typical (nondecremental) accessory pathways (APs) (62% right free wall, 34% right septal, and 4% left sided), 17 other supraventricular tachycardias (1 ectopic atrial, 7 AV reentry, 5 Mahaim, and 4 intra‐atrial reentry tachycardias), and 1 ventricular mechanism were mapped. Thirty‐four (52%) of 65 patients had a single AP (21 right free wall, 10 septal, and 3 left); 19 (29%) of 65 patients multiple APs; 6 (9%) of 65 patients a single AP plus a non‐AP mechanism; and 6 (9%) of 65 patients non‐AP mechanism(s) only. REA acute success rates and recurrence rates for right free wall, right septal, and other mechanisms were 79%/32%, 89%/29%, and 75%/27%. Mild DOTR and a body surface area (BSA) ≤ 1.7 m 2 independently predicted a better acute success rate. BSA ≤ 1.7 m 2 also predicted long‐term success. Conclusion: In this patient subset, life‐threatening arrhythmias and multiple electrophysiologic mechanisms are commonly encountered during REA. Mild DOTR and a BSA ≥ 1.7 m 2 predict a higher acute success rate. While acute success rates are relatively high, recurrence is frequent.