Hypoplastic Left Heart Syndrome (HLHS)

January 5, 2020 0 By Bertrand Dibbert


Hypoplastic Left Heart Syndrome (HLHS). The term “hypoplastic” refers to underdevelopment
of a tissue or organ. In HLHS, most of the left-sided heart structures
are hypoplastic. This is a view from inside the right atrium. An atrial septal defect, or ASD, is a hole
between the right and left atria. This is a view from inside the left atrium. The mitral valve is also hypoplastic and is
either severely narrowed or not formed at all. The 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. In HLHS, a PDA (Patent Ductus Arteriosus)
exists to provide blood flow from the pulmonary artery to the body. Babies with HLHS have
a bluish appearance, known as cyanosis, as a result of mixing oxygen-rich and oxygen-poor
blood. If the PDA closes, the baby will become critically ill. A continuous IV medication
called prostaglandin is needed to keep the PDA open after birth. Surgery is typically performed within the
first few weeks of life.