Hypoplastic left heart syndrome

[Britney]

Hypoplastic left heart syndrome is a birth defect in which the left side of the heart, including the lower heart chamber (left ventricle), heart valves (mitral and aortic valves), and aorta, does not develop sufficiently. Newborns with hypoplastic left heart syndrome also have an atrial septal defect (ASD) and a patent ductus arteriosus.

Hypoplastic left heart syndrome causes heart failure—the heart pumps less than normal amount of blood—and eventually death.
Diagnosis is by echocardiography.
Treatment is with a series of surgical procedures or with heart transplantation.

(See also Overview of Heart Defects.)
Hypoplastic is a medical term for underdeveloped. Hypoplastic left heart syndrome (HLHS) accounts for 2 to 4% of birth defects of the heart. Because the left side of the heart is underdeveloped, oxygenated blood coming into the left heart from the lungs is diverted into the right side of the heart through the atrial septal defect, where it mixes with deoxygenated blood returning to the heart from the body. This relatively deoxygenated blood exits the right heart to the lungs and through the ductus arteriosus to the body. The ductus arteriosus is a blood vessel connecting the two great arteries leaving the heart, the pulmonary artery and the aorta (see Normal Fetal Circulation). In the womb and during the first few days of life, the ductus is open. Blood flow to the body is maintained only because the ductus arteriosus remains open. Once the ductus closes, as it normally does after birth, very little blood flows to the body. If the defect is not repaired immediately, the infant will die.