Hypoplasia can affect the heart, which typically results in the failure of either the right ventricle or the<unk>  ventricle to develop adequately, leaving only one side of the heart capable of pumping blood to the body and lungs.  Hypoplasia of the heart is rare but is the most serious form of congenital heart defect; it is called<unk>  when it affects the<unk>  side of the heart and hypoplastic right heart syndrome when it affects the right side of the heart.  In both conditions, the presence of a patent ductus arteriosus (and, when hypoplasia affects the right side of the heart, a patent foramen ovale) is vital to the infant's ability to survive until emergency heart surgery can be performed, since without these pathways blood cannot circulate to the body (or lungs, depending on which side of the heart is defective).  Hypoplasia of the heart is generally a cyanotic heart defect.<unk>  is a rare congenital heart defect in which the<unk>  side of the heart is severely underdeveloped. In babies with<unk> S, the aorta and<unk>  ventricle are very small, and the aortic and mitral valves are either too small to allow sufficient blood flow or are atretic (closed) altogether.  As blood returns from the lungs to the<unk>  atrium, it must pass through an atrial septal defect to the right side of the heart.
Hypoplastic left heart syndrome
Hypoplastic right heart syndrome
Aortic arch anomalies
Single ventricle
Pulmonary atresia
Double outlet right ventricle
Congenital diaphragmatic hernia
Total anomalous pulmonary venous connection