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Hypoplastic Left Heart with Restrictive Septum

What is Hypoplastic Left Heart Syndrome?

Hypoplastic left heart syndrome (HLHS) refers to the underdevelopment of the left side of the heart, including the aorta, aortic valve, mitral valve and the left ventricle. Babies with HLHS do not usually have other associated anomalies. The hypoplastic left heart is unable to pump enough blood to meet the body's demands and requires surgery shortly after birth. HLHS occurs in about 1 in every 5,000 births. Two-thirds of those affected are boys.

Circulation in a baby with classic HLHS utilizes a small opening between the two upper chambers of the heart called the foramen ovale, to move blood from the left atrium to the right atrium. If there is a severely restrictive or absent atrial defect, pressure rises in the left atrium. This causes severe and potentially irreversible damage to the blood vessels in the lungs.

The baby will be unable to supply enough oxygenated blood to the body for survival and an emergent balloon atrial septostomy (creating an opening in the atrial septal wall) is required.

For more information please visit to the Congenital Heart Center at the following link: Hypoplastic Left Heart Syndrome

How is the diagnosis made?

Prenatal ultrasound can identify a problem with the baby's heart. The diagnosis of HLHS is made by fetal echocardiogram as early as 16 weeks gestation.

Is there fetal treatment for HLHS?

Fetal treatment is available for select fetuses with HLHS and a restrictive atrial septal defect. Potential candidates for fetal cardiac intervention will receive a comprehensive evaluation at the University of Michigan Prenatal Heart Center.

The fetal cardiac procedure may require a maternal skin incision to gain access to the atrium or, depending on fetal position, may be performed percutaneously. A balloon catheter is inserted to open the atrial septal defect. This may prevent irreversible damage to the pulmonary vasculature, and also prevent the need for emergent, high-risk intervention at birth. Furthermore, this intervention may lead to improved heart development.

What other treatment is available for HLHS?

Treatment of HLHS involves either a three-staged surgical repair or heart transplantation. Please consult with your doctor or follow the link for more information

Are there special considerations planned for the delivery?

It is recommendedthat babies with HLHS be delivered in a facility familiar with high-risk deliveries with a neonatal intensive care unit, pediatric cardiologist and pediatric cardiothoracic surgeons to address the significant medical needs of these infants. A Cesarean section is recommended when indicated for obstetrical reasons.

Can this happen again with another pregnancy?

The majority of HLHS is due to a random (sporadic) event; however, in some families, there is an increased risk for future affected pregnancies. The approximated genetic risk for siblings of a child with isolated HLHS is 3%. If a chromosome change is identified, the chance of HLHS with future pregnancies is dependent on the type of chromosome change. Prenatal diagnostic testing may be available in some cases. Your doctor and a genetic counselor will meet with you and discuss your family's risk.