What Can Cause Pulmonary Vascular Disease in Functionally Single Ventricle

Definition of “functionally single ventricle” includes a wide spectrum of anatomical variants such as double inlet left or right ventricle, mitral or tricuspid atresia, unbalanced atrioventricular canal, heterotaxy syndrome with one normally developed ventricle or other congenital heart defects with severe hypoplasia of one of the ventricles [2]. Anatomical and hemodynamic abnormalities in these congenital heart lesions are characterized by presence of a common ventricular chamber, where blood from the left and right atrium mixes and then enters the aorta and pulmonary artery. This can cause pulmonary hypervolemia and hypertension (in patients without pulmonary stenosis), difficulties with blood outflow (in patients with mitral atresia/stenosis combined with restrictive atrial septal defect), intake of highly oxygenated blood into the pulmonary artery (in patients with transposition of the great arteries) as well as systemic hypoxemia and polycythemia.