Hypoplastic (HI-puh-plas-tik) left heart syndrome (HLHS) is a rare and serious
defect in which the structures of the left side of the heart
(the left ventricle, the mitral valve, and the aortic valve) are underdeveloped. As
a result, blood cannot be adequately
pumped throughout the body.
More to Know
Hypoplastic left heart syndrome is present at birth (congenital)
and has no known cause. It is usually diagnosed within the first few days of life.
Without surgery to repair the heart, HLHS is fatal.
Symptoms of HLHS include blue or gray skin color (cyanosis), rapid breathing, pounding
heart, shortness of breath, cold hands and feet, weak pulse, unusual drowsiness and
Once diagnosed with HLHS, most babies will undergo a series of three operations
beginning shortly after birth and ending at 3 years of age. For some babies, heart
transplant is the best option if a donated organ is available.
Keep in Mind
While many babies now survive HLHS, they need to be monitored closely by a cardiologist
for the rest of their lives. Many complications can occur with HLHS and sometimes
additional heart surgery or even heart transplant may be necessary as children born
with HLHS get older.
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