Symptoms and causes

Babies born with hypoplastic left heart syndrome usually are seriously ill soon after birth. Hypoplastic left heart syndrome symptoms include:

  • Grayish-blue skin color (cyanosis)
  • Rapid, difficult breathing
  • Poor feeding
  • Cold hands and feet
  • Being unusually drowsy or inactive

In a baby with hypoplastic left heart syndrome, if the natural connections between the heart's left and right sides (foramen ovale and ductus arteriosus) are allowed to close, he or she may go into shock and may die. Signs of shock include:

  • Cool, clammy skin that may be pale or gray
  • A weak and rapid pulse
  • Abnormal breathing that may be either slow and shallow or very rapid
  • Dilated pupils
  • Lackluster eyes that seem to stare

A baby who is in shock may be conscious or unconscious. If you suspect your baby is in shock, immediately call 911 or your local emergency number.

Hypoplastic left heart syndrome occurs during fetal growth when the baby's heart is developing. The cause is unknown. However, if your family has one child with hypoplastic left heart syndrome, the risk of having another with a similar condition is increased.

A normal heart has four chambers, two on the right and two on the left. In performing its basic job — pumping blood throughout the body — the heart uses its left and right sides for different tasks. The right side moves blood to the lungs. In the lungs, oxygen enriches the blood, which then circulates to the heart's left side. The left side of the heart pumps blood into a large vessel called the aorta, which circulates the oxygen-rich blood to the rest of the body.

If you already have a child with hypoplastic left heart syndrome, you're at a higher risk of having another baby with this condition or a similar condition.

Beyond family history, there are no clear risk factors for hypoplastic left heart syndrome.

Without surgery, hypoplastic left heart syndrome is fatal, usually within the first few weeks of life.

With treatment, many babies survive, although most will have complications later in life. Some of the complications may include:

  • Tiring easily when participating in sports or other exercise
  • Heart rhythm abnormalities (arrhythmias)
  • Fluid buildup in the lungs, abdomen, legs and feet (edema)
  • Formation of blood clots that may lead to a pulmonary embolism or stroke
  • Developmental problems related to the brain and nervous system
  • Need for additional heart surgery or transplantation
Aug. 12, 2017
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