A cyanotic congenital heart defect
Blood is pumped through a single truncal valve into a truncal artery which gives rise to the aorta and the pulmonary arteries
Associated with large VSD in most patients
Incidence ranges from 6 to 10 per 100,000 live births, accounts for 4% of all congenital heart disease 
PVR is high in the newborn infant, so there is little left to right shunting at birth
Over first several weeks of life, PVR drops, left to right shunting increases, leading to heart failure
Mixing of systemic and pulmonary blood leads to mild to moderate cyanosis
Pulmonary vascular obstructive disease may develop in surgically uncorrected patients
Truncus arteriosus
Cyanotic
Patent ductus arteriosus
Tetralogy of fallot
Ebstein anomaly
Total anomalous pulmonary venous return
Tricuspid atresia
Transposition of the great arteries