Hypoplastic Left Heart Syndrome (HLHS) | Symptoms and Causes

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What are the symptoms of hypoplastic left heart syndrome?

In most cases, children born with hypoplastic left heart syndrome (HLHS) appear healthy. The typical baby with HLHS initially may be nearly indistinguishable from a baby without it.

When a baby is not diagnosed during pregnancy, symptoms may develop within the first few hours or days of life:

  • rapid breathing or shortness of breath
  • rapid heartbeat or pounding heart
  • poor suckling and feeding
  • cold extremities (poor perfusion)
  • blue color of the skin, lips and nailbeds (cyanosis)
  • weakness

What causes hypoplastic left heart syndrome?

It’s important to understand that as parents, you’ve done nothing to cause HLHS and its associated defects. HLHS is the result of under-development of sections of the fetal heart during the first eight weeks of pregnancy. But it’s not understood why some babies’ hearts don’t develop normally. Congenital heart defects usually occur sporadically with no clear reason for their development.

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