Diffuse bilateral pulmonary arteriovenous fistulas developed in a cyanotic child with left atrial isomerism, consisting of an interrupted inferior vena cava with continuation of the hemiazygos vein to the isolated left superior vena cava, soon after she underwent a Kawashima operation that left the hepatic veins draining into the common atrium. The fistulas regressed after the hepatic veins were connected to the confluent pulmonary arteries with a left lateral atrial tunnel.