The Pediatric Radiofrequency Ablation Registry's experience with Ebstein's anomaly. Pediatric Electrophysiology...

Abnormal anatomy and complex electrophysiology in patients with Ebstein's anomaly of the tricuspid valve may confound attempts at radiofrequency ablation (RFA).

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. RFA 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) < or = 1.7 m2 independently predicted a better acute success rate. BSA < or = 1.7 m2 also predicted long-term success.

In this patient subset, life-threatening arrhythmias and multiple electrophysiologic mechanisms are commonly encountered during RFA. Mild DOTR and a BSA < or = 1.7 m2 predict a higher acute success rate. While acute success rates are relatively high, recurrence is frequent.