Prolonged and decremental antegrade conduction properties in right anterior accessory connections: Wide QRS antidromic tachycardia of left bundle branch block pattern without Wolff-Parkinson-White configuration in sinus rhythm.

Four patients are described who had long conduction times and decremental conduction through right anterior accessory connections. None had Wolff-Parkinson-White syndrome on their ECG. Each had recurrent sustained wide QRS tachycardia due to antegrade conduction through the accessory connection. Three patients underwent epicardial mapping and successful surgical division of their accessory connection. Two of the three had a second accessory connection that was also divided surgically. Each of the three are free of tachycardia without medication. It is postulated that these accessory connections represent the remnants of anterior atrioventricular ring tissue described by Anderson.