Fig. 2. Schematic representations of normal heart, Blalock Taussig shunt, and Fontan circulation. SVC = superior vena cava; IVC = inferior vena cava; RA = right atrium; RV = right ventricle; PA = pulmonary artery; LPA = left pulmonary artery; RPA = right pulmonary artery; LV = left ventricle; LA = left atrium; Ao = aorta.