Surpassing the complex substrate of accessory pathways ablation in ebstein anomaly

Abstract Funding Acknowledgements Type of funding sources: None. Background and Aims Data regarding long-term follow-up radiofrequency catheter ablation (RFCA) accessory pathways (APs) in patients (P) with Ebstein's anomaly are limited. This type procedure is considered challenging due to multiple broad APs. The present study aimed describe the electrophysiological features APs P anomaly, report our RFCA experience an open-window electroanatomic 3D mapping using high-density catheters these patients. Methods results A retrospective 15 consecutive Ebstein who underwent electrophysiologic from 2013 2022. There were a total 21 manifested non-decremental mainly located on posterior, posteroseptal, posterolateral tricuspid annulus. index was unsuccessful six P, need for redo procedure. performed (Pentaray, Biosense or HD-Grid, Abbott), annotation algorithm (Abbott's NavX Precision BiosenseWebster Carto3), guided by CT integration intracardiac echo. Broad documented all (width range 2-15cm) successfully ablated. In one AP encompassed ¾ TA, resulting complete AV block after procedure, having fitted pacemaker. All remained free tachycardias during 15±8 months follow-up, majority (n=12) sinus rhythm morphology right bundle branch block, while three showed narrow QRS. Conclusions challenging, but safe, has high success rate. predominantly right-sided, manifest localized lower half anatomic Some have widths. this population, new high-resolution catheters, annotation, produce improved anatomical resolution APs, increasing odds success.