Neonatal tachypnea, tachycardia, cyanosis, third
heart sound, systolic murmur, and hepatomegaly. Chest radiograph may show
cardiomegaly and increased pulmonary vasculature. Neonatal cardiovascular
palliation is achieved by the Norwood procedure, which results in the right
ventricle supplying systemic circulation. The pulmonary circulation is
supplied by a systemic-to-pulmonary arterial shunt (e.g., Blalock-Taussig
shunt). An atrial septectomy is performed to allow pulmonary venous blood to
flow freely into the right atrium. At approximately 6 months, once pulmonary
vascular resistance has fallen from the high neonatal level, a hemi-Fontan
or bidirectional Glenn shunt is performed. This procedure results in the
pulmonary circulation being supplied by the superior vena cava (passive
process relies on superior vena cava pressure being greater than pulmonary
venous pressure to maintain flow). The Fontan procedure is completed at
least 6 months later to allow development of optimal right ventricular
function. The completed procedure results in both superior vena cava and
inferior vena cava blood being diverted to passively supply the pulmonary
circulation. Heart transplantation may be required.