There is no left atrium to receive pulmonary venous drainage,
and total anomalous pulmonary venous drainage into a systemic vein is seen in > 50% of cases.
Right atrial isomerism is usually associated with severe cyanotic heart disease in infancy.
Accompanying heart defects may include transposition of the great arteries, common atrioventricular
(AV) valve, ventricular hypoplasia or single ventricle physiology, pulmonary atresia and pulmonary vein
obstruction.
The syndrome is associated with a poor prognosis and high mortality rate (80%-90%) in the first year of life.