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Hypoplastic Left Heart Syndrome
What is it?
Hypoplastic left heart syndrome is a rare and serious birth defect in which the left side of the heart is not all the way developed.
The left ventricle pumps blood to the aorta and gives oxygen-rich blood to the body.
In hypoplastic left heart syndrome, the left ventricle is hypoplastic (not developed or too small). The left ventricle is not working because the valves leading into and out of the left ventricle — the mitral and aortic valves — are not there or are very small.
The aorta is also hypoplastic (small).
How is it treated?
Surgery is needed quickly. Babies either get a series of three surgeries, called the Fontan operation, or a heart transplant.
Hypoplastic left heart syndrome is one of the single ventricle heart defects because there is only one pumping chamber in the heart. Single-ventricle defects are some of the most complex heart birth defects.