ABSTRACT
AVSDs represent a spectrum of septal defects that may be limited to the atrial level or also involve an inlet VSD, in combination with malformed AV valves. They share in common an inferiorly and posteriorly displaced AV node associated with a higher incidence of AV block. IART propagating around the right AV annulus that is dependent on the cavoannular isthmus is the most commonly encountered atrial tachyarrhythmia. The cavoannular ablation line should be placed more laterally so as to minimize risks of damaging the displaced AV node. Other atrial tachyarrhythmias encountered include right lateral wall IART, focal atrial tachycardia, bi-atrial circuits, AFib, and twin AV node reentrant tachycardia. Catheter ablation in patients with AVSD should be performed in centers with expertise in CHD and after a thorough review of anatomical complexities, surgical details, and documented arrhythmias.
