A right axillary A-V fistula has been made in a 13-year-old patient with tricuspid atresia who, after undergoing two unsuccessful attempts in infancy to establish a left Blalock shunt and having had a superior vena cava-right pulmonary artery (SVC-RPA) shunt at age 3, showed increasing disability and profound cyanosis (HCT 80%). One year following creation of the fistula there is marked increase in exercise tolerance, a decrease in HCT to 56%, and an increase in pO2from 57 to 105 mm Hg.Creation of an axillary A-V fistula in patients with an SVC-RPA shunt is an effective means of supplementing blood flow to the right lung by increasing the flow through the shunt and by giving it a pulsatile character, and, eventually, by decreasing the blood's viscosity. Axillary A-V fistula may be required by many patients with a cava-pulmonary shunt who have inadequate perfusion of the contralateral lung and clinical deterioration.