Electrophysiological abnormalities after Mustard's operation for transposition of the great arteries.

Because of the frequent occurrence of significant dysrhythmias after Mustard's operation for transposition of the great arteries, electrophysiological studies were performed in i6 patients during postoperative cardiac catheterization. Intracavitary electricalpotentials were recordedfrom the conduction system in all i6patients. In 9 of these patients, the stability of the atrioventricular conduction system during rapid atrial pacing was tested, as well as the subsequent promptness ofpacemaker recovery.