Accessory atrioventricular pathway (AP) conduction is found in 33% of patients with Ebstein anomaly, including atriofascicular (AF) pathways in 5%–8%.1 AF pathways typically conduct anterograde only, with decremental conduction properties analogous to the atrioventricular node (AVN), and participate almost exclusively in antidromic atrioventricular reciprocating tachycardia (AVRT).1,2 Ablation of AF APs may be challenging in such patients due to the deviation from normal anatomic structure, potential for multiple APs, difficulty obtaining catheter stability, hemodynamic instability in tachycardia, and concerns for catheter-induced mechanical conduction block.
