Absence of a resetting phenomenon suggests that a sling works as a part of the supraventricular tachycardia circuit involving twin atrioventricular nodes: A case of corrected transposition of the great arteries

Introduction In corrected transposition of the great arteries (CTGA), the presence of 2 atrioventricular nodes (twin AVNs), their Purkinje systems, and a specific conduction system (Mönckeberg sling) connecting them to each other has been demonstrated using histologic and electrophysiological techniques.. Twin AVNs can induce supraventricular tachycardia (SVT) as a preoperative, perioperative, or postoperative arrhythmic complication. Therefore, preoperative electrophysiological evaluation is important. However, clinical reports describing the electrophysiological properties of the sling are limited. In this case report, we confirmed the presence of a sling between twin AVNs and determined that it functioned as a part of the reentrant circuit of SVT associated with the twin AVNs.