Hypoplastic Left Heart Syndrome (HLHS)

Hypoplastic Left Heart Syndrome (HLHS) refers to underdevelopment of a tissue or organ. In HLHS, most of the left-sided heart structures are hypoplastic. There is also an Atrial Septic Defect, or ASD, which is a hole between the right and left atria. The mitral valve is also hypoplastic and is either severely narrowed or not formed at all. This abnormal mitral valve prevents blood from entering the left ventricle. Blood flow is then diverted across the ASD and into the right atrium. Blood return from both the lungs and body flows into the right ventricle. The right ventricle pumps blood to both the lungs and the body. This is why HLHS is referred to as a single ventricle defect. Also, patent ductus arteriosus, or PDA, exists to provide blood flow from the pulmonary artery to the body. Babies with HLHS sometimes have a bluish appearance as a result of mixing oxygen-rich and oxygen-poor blood. 

Watch the following video animation to learn more about this condition and treatment options.

For additional information, or to make an appointment, please contact the center for Advanced Fetal Care at 410-328-3865.