Accessory atrioventricular node and bundle: a cause of antidromic reentry tachycardia

Two patients are described with antidromic reentry tachycardia successfully treated by interruption of an anterior septal accessory atrioventricular node and bundle. This anomalous connection resembles an atrioventricular conduction sling seen in complex congenital heart malformations. It has atrioventricular node-like properties, is located in the anterior septal area, will only conduct antegrade, and has an insulated connection to the right bundle branch. Rather than nodoventricular, nodofascicular, atriofascicular, or Mahaim, a more appropriate label for the connection is accessory atrioventricular node and bundle.