Hypoplastic left heart syndrome (HLHS) is a rare birth defect of a baby's heart.
The left side of the heart doesn't grow as it should, making it smaller and weaker
The left side of the heart is supposed to pump blood out to the body. But a baby's
heart with HLHS can't do the job. This makes a baby very sick. Without medicines and
a series of three surgeries to rebuild the heart, babies with HLHS won't survive.
The left side of the heart can't be fixed, so the goal of the surgeries is to rebuild
parts of the heart and "redirect" the way blood flows to and from the body.
Soon after birth, a baby with HLHS needs around-the-clock care in a hospital for
the first weeks or months of life.
How Does the Heart Work?
The heart is a muscle that pumps blood. It acts like two pumps in one. The pumps
are called ventricles and each has an important job:
the lungs, blood fills up with oxygen and gets rid of carbon dioxide.
The left ventricle
gets the blood from the lungs and pumps it out through the aorta
to the body.
Because it pumps blood to the entire body, the left ventricle
is a stronger pump than the right ventricle.
What Happens in Hypoplastic Left Heart Syndrome?
With hypoplastic left heart syndrome:
The left ventricle and aorta are too small to pump enough blood to the body.
The right ventricle, which is only supposed to pump blood to the lungs, pumps
blood to the lungs and the body through an extra pathway called a patent
ductus arteriosis (PDA). That means the right ventricle gets overworked.
Babies with HLHS are almost always born with an atrial
septal defect (ASD). This is a hole in the upper part of the heart. It lets blood
with oxygen mix with blood low on oxygen. Then the right ventricle pumps the blood
to the lungs and the body.
What Are the Signs & Symptoms of Hypoplastic Left Heart Syndrome?
Within a few hours to a day or so after birth, a newborn with undiagnosed HLHS
blue or grayish coloring of the skin and nails
lethargy (very little activity)
weak pulses in the arms and legs
few wet diapers
What Causes Hypoplastic Left Heart Syndrome?
HLHS is a birth defect that happens when a baby is growing in the womb. No one
knows exactly what causes it, but it could have a mix of causes, including a baby's genes (DNA).
How Is Hypoplastic Left Heart Syndrome Diagnosed?
Hypoplastic left heart syndrome can be diagnosed with: