Hypoplastic left heart syndrome is a rare heart defect. In a normal heart, the blood flows in from the body to the right atrium. It then goes into the right ventricle. Next, the blood travels to the lungs through the pulmonary valve. Here, it picks up fresh oxygen. The blood returns to the left atrium and goes into the left ventricle. The blood then moves out to the rest of the body.

With this syndrome, structures on the left side of the heart, which includes the aorta, aortic valve, left ventricle, and mitral valve, may be:

  • Too small
  • Absent
  • Abnormally developed

Since the heart cannot function properly, oxygen-rich blood flow to the body is limited. This condition requires immediate care from a doctor.

Heart Chambers and Valves
heart anatomy
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Blood Flow Through the Heart
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This is a congenital heart defect. This means that the heart forms incorrectly when the baby develops in the womb. The baby is born with the condition. It is not known why the heart forms this way.