Single coronary artery with a fistula to the main pulmonary artery in a patient with tetralogy of Fallot.

The presence of a single coronary artery arising in the anterior cusp and terminating in a large fistula to the main pulmonary artery was noted during the preoperative evaluation of a patient with tetralogy of Fallot. Recognition of this rare association dictated the use of a valved conduit to avoid injury to the left anterior descending coronary as it crossed the right ventricular outflow tract and permitted abolition of intracardiac shunting by ligation of the fistula. It is postulated that the increasing arterial saturation noted in this patient prior to intracardiac repair may have been related in part to progressive augmentation in flow through the coronary fistula to the main pulmonary artery.