Congenital heart defects (CHDs) are problems present at birth that affect the structure and function of the heart.

CHDs are America’s most common birth defect, affecting nearly 40,000 babies each year in the U.S alone. This equates to 1 child every 15 minutes.

Some CHDs are diagnosed during pregnancy using a special type of ultrasound called a fetal echocardiogram. However, some heart defects are not found during pregnancy. In these cases, heart defects may be detected at birth or as the child ages.

As medical care and treatment have advanced, thanks to research, infants with CHDs are living longer and healthier lives. Even with improved treatments, people with CHDs are not cured, even if their heart defect has been repaired. People with a CHD can develop other health problems over time, depending on their specific heart defect, the number of heart defects they have, and the severity of their heart defect.

There are many types of congenital heart defects (CHDs) with different degrees of severity based on size, location, and other associated defects. In more severe forms of CHD, blood vessels or heart chambers may be missing, poorly formed, or in the wrong place. About 1 in every 4 babies born with a CHD has a critical congenital heart defect.

Hypoplastic-Left-Heart Syndrome (HLHS) occurs in about 1% of all congenital heart defect cases. The left ventricle (LV) is hypoplastic, meaning it is under-developed or not functioning. Essentially, the LV is not functional because the valves leading into and out of the LV, the mitral and aortic valves, are severely stenosed (tight), or atretic, meaning impassable or not allowing any blood flow. In addition, the main route out of the left ventricle, the aorta, is also hypoplastic. The newborn baby may initially appear to be well during the first hours or even days of life. However, as the baby breathes on its own, the pressure in its lungs begins to decrease. Also, the patent ductus arteriosus, a tiny vessel between the aorta and pulmonary artery, will begin to close after birth. Then, the baby will appear sicker, breathing quickly, not feeding, showing a faster heart beat and congested lungs. HLHS is considered a critical congenital heart defect.