What is Hypoplastic Left Heart Syndrome?
Hypoplastic left heart syndrome (HLHS) is a congenital birth defect, which means it is present at birth. Congenital heart defects affect 1 in every 125 infants (about 35,000) and HLHS accounts for 1 to 3.8 percent of all congenital heart defects. (1)
Heart defects are the leading cause of birth defect-related deaths. (2)
In this case, the heart has an underdeveloped left side.
The left side normally pumps oxygenated blood to the rest of the body through the aorta. A hypoplastic left side is unable to do that.
Without oxygen, the body cannot function. In some cases the mitral valve, aortic valve and aorta are also affected. To see a diagram, click here.
Causes and Signs of Hypoplastic Left Heart Syndrome
There are usually no immediate after-birth signs of HLHS such as a heart murmur. Within a few hours, however, the baby will start showing:
• Cyanosis (skin turns a grayish-blue color)
• Difficult/labored and rapid breathing
• Cold hands and feet
• Poor pulse
• Poor suckling and feeding
• Pounding heart
• Drowsiness or inactivity
Research has yet to determine why congenital heart defects happen, but genetic and environmental factors may each play a role.
Women who contract German measles (rubella) during the first trimester are at increased risk for having a baby with a heart defect, as are mothers who take certain anti-seizure medications, the antibiotic trimethoprim-sulfonamide (sometimes used to treat urinary-tract infections), isotretinoin (acne medication – Accutane), and thalidomide. (2)
“At least 30 percent of children with chromosomal abnormalities, such as Down syndrome ... and Turner syndrome, have heart defects.” (2).
Obviously, parents with a history of congenital heart disease also are at increased risk of having a baby with this birth defect as well.
Treatment of Hypoplastic Left Heart Syndrome
HLHS “can be diagnosed by fetal echocardiography between 18 and 22 weeks of gestation” (1).