A cyanotic congenital heart defect
Absence of<unk>  valve resulting in absence of communication between the right atrium and right ventricle
Due to absence of communication with the right ventricle, RV becomes either under-developed or entirely absent
Third most common cyanotic congenital heart disease 
ASD (100%)
Right ventricular hypoplasia (100%)
VSD (95%)
Pulmonary outflow obstruction (75%)
Transposition of the great arteries (28%)
Blood from the RA must exit through the ASD (no<unk>  valve)
Right to left atrial shunting allows deoxygenated systemic venous blood to enter the LA, then LV
Cyanosis is present due to mixing of systemic and pulmonary venous blood in the LA
Tricuspid atresia
Cyanotic
Ebstein anomaly
Tetralogy of fallot
Transposition of the great arteries
Total anomalous pulmonary venous return
Atrio-esophageal fistula
Ventricular septal defect