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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 (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

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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 is developing in the womb. The baby is born with the condition. It is not known why the heart forms this way.

These factors increase your chance of having a child with hypoplastic left heart syndrome:

• Previous pregnancy with fetal heart abnormalities or fetal loss
• Family history of congenital heart defect

Symptoms usually appear within days after birth. Tell the doctor if you notice the following in your infant or child:

• Blue/gray skin color
• Cool skin
• Rapid or difficult breathing
• High heart rate
• Sweaty, clammy skin
• Poor feeding

These symptoms may be caused by other conditions. If your child has any of these, tell the doctor right away.

Your doctor will:

• Ask about your child’s symptoms and medical history
• Do a physical exam

Tests may include:

• Echocardiogram —a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
• Chest x-ray —imaging test that uses low amounts of radiation to get a picture of the chest
• Electrocardiogram (ECG, EKG)—a test that records the heart’s activity by measuring electrical currents through the heart muscle
• MRI scan —a test that uses magnetic waves to make pictures of structures inside the body
• CT scan —a type of x-ray that uses a computer to make pictures of structures inside the body
• Cardiac catheterization —a thin tube is threaded through a vein to the heart where blood samples and blood pressure are measured

Talk with your doctor about the best treatment plan for your child. Some defects may be so severe that they are difficult to treat. Treatment options include:

There is no way to prevent this condition. Getting appropriate prenatal care is always important.