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Genetic and Rare Diseases Information Center (GARD)

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Hypoplastic left heart syndrome

Other Names for this Disease
  • HLHS
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What are the signs and symptoms of hypoplastic left heart syndrome (HLHS)?

Normally, oxygen-poor blood is pumped through the right side of the heart to the lungs, where it gains oxygen and returns to the left side of the heart. The oxygen-rich blood is then pumped from the left side of the heart to the rest of the body. At birth, all babies also have two connections, or shunts, between the two sides of the heart; however, within a few days of birth these connections close. In those with HLHS, the underdeveloped left side of the heart is unable to provide enough blood flow to the body. The normal shunts present at birth help to direct blood to the body; when these connections close the oxygen-rich blood supply decreases.[1]

At first, a newborn with HLHS may appear normal. Symptoms usually occur in the first few hours of life, although it may take up to a few days to develop symptoms. These symptoms may include:[2]

  • Bluish (cyanosis) or poor skin color
  • Cold hands and feet (extremities)
  • Lethargy
  • Poor pulse
  • Poor suckling and feeding
  • Pounding heart
  • Rapid breathing
  • Shortness of breath

In healthy newborns, bluish color in the hands and feet is a response to cold (this reaction is called peripheral cyanosis). However, a bluish color in the chest or abdomen, lips, and tongue is abnormal (called central cyanosis). It is a sign that there is not enough oxygen in the blood. Central cyanosis often increases with crying.[2]
Last updated: 7/21/2011

  1. Facts about Hypoplastic Left Heart Syndrome. Centers for Disease Control and Prevention. April 2011; Accessed 7/21/2011.
  2. Schumacher KR. Hypoplastic left heart syndrome. MedlinePlus. December 2009; Accessed 7/21/2011.