Hypoplastic left heart syndrome (HLHS) describes a group of complex congenital heart defects that occur in newborns. HLHS is characterized by the underdevelopment of the left atrium and ventricle of the heart. Additionally, the valve that connects these two chambers (the mitral orifice) and the aortic valve are narrowed or closed. The defects on the left side put unusual strain on the right side of the heart, causing enlargement of the chambers and the vessels on this side. When the baby is born, she or he may appear normal, but within a few days the baby will develop a bluish color to the skin (cyanosis and hypoperfusion). The infant will soon go into shock, and emergency surgery is usually required. Problems in cognition are usually the result of neurological complications associated with hypoperfusion of the brain and other structures of the central nervous system (CNS).
A serious congenital disease (present at birth) in which severe malformation of the chambers, valves, and blood vessels on the left side of the heart prevents blood from being pumped efficiently into the rest of the body. Such infants are treated by heart transplant or the Norwood procedure, a series of three open- heart surgeries performed from infancy through the toddler years. Chances for survival past childhood for those with hypoplastic left heart syndrome who have undergone either heart transplant or the Norwood procedure remain unknown.
A severe type of birth defect related to the heart, where a baby is born with an improperly developed left ventricle, the heart’s main pumping chamber. This condition often coexists with other heart abnormalities. Additionally, the aorta, a major artery, is also malformed, and blood can only reach it through a connecting duct known as the ductus arteriosus, which bridges the aorta and the pulmonary artery.
Initially, the baby may appear healthy at birth. Nevertheless, within a day or two, the ductus arteriosus naturally seals off, leading to the baby suddenly deteriorating, turning pale, and experiencing difficulty breathing. The hypoplastic left-heart syndrome can be addressed through surgical intervention, occasionally requiring a heart transplant.