Collateral arteries arising from the coronary circulation in tetralogy of Fallot.

Semi-selective aortic root and some selective coronary angiographic studies were performed in 330 patients with tetralogy of Fallot over a period of four years. Collateral vessels arising from the coronary arteries were found in 11 cases and a direct communication between the coronary artery and pulmonary arteries in one case (3.6%). Electrocardiographic features of myocardial ischaemia were not present in any patient. It is important to localize the collateral arteries since coronary steal and myocardial ischaemia have been known to occur in their presence.