Recurrent syncope due to late paroxysmal atrioventricular block after Senning repair

A 14-year old male with d-transposition of the large arteries and Senning repair should have presented four syncopal episodes with spontaneous recovery the year prior to admission is reported. Following conventional diagnostic procedures, including electrophysiologic study, no abnormalities were detected. Therefore, an insertable Holter was implanted, and two months later the patient presented a syncopal episode secondary to 15 second paroxysmal atrioventricular block. A dual chamber pacemaker was implantated and nine months later the patient remains syncope-free.