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Hypoplastic Left Heart Syndrome (HLHS)


Overview

Hypoplastic left heart syndrome (HLHS) is when the structures on the left side of the heart are underdeveloped (hypoplastic) and too small to provide enough oxygen-rich blood for the body.

The left ventricle is unable to function effectively and other left heart structures, including the mitral valve, aortic valve and aorta, are also often underdeveloped. This heart defect is often detected while the baby is not yet born. Once born, the baby may appear fine until the patent ductus arteriosus (PDA) closes. At that time, no blood will reach the body and the baby will go into shock and die.

Knowing about this condition before birth is helpful because a medication called prostaglandin E is used to keep the PDA open until surgery can be performed.


Normal heart – in a healthy heart with proper blood flow, the blue droplets representing oxygen-poor blood travel to the lungs, and the red oxygen-rich droplets circulate through the body.

A heart with hypoplastic left heart syndrome (HLHS)



Treatments

If hypoplastic left heart syndrome is identified before birth, the Inova Children’s Fetal Care program will work with pediatric cardiac surgeons, pediatric cardiologists, neonatologists, and your family to plan and coordinate your baby’s postnatal care to ensure the best possible outcome. As soon as your baby is born, our team will begin treatment.

Treatment options depend on the extent of the disease and other variables, but treatment right after birth typically includes:

  • IV (intravenous) medication to keep the PDA open
  • Intravenous fluids
  • Respiratory support (a breathing machine), needed by some babies
  • Balloon atrial septostomy, needed by some babies, to create an opening in the atrial septum between the upper chambers of the heart to improve the mixing of oxygen-rich blood and oxygen-poor blood

When treating hypoplastic left heart syndrome, three surgeries, depicted below in the animated videos, are performed in sequence in order to allow the heart to better function:

  • Norwood procedure
  • Bi-directional Glenn procedure
  • Fontan procedure

Norwood procedure – performed within a few days of your baby's birth. This surgery is complex and includes a number of steps including:

  • General anesthesia
  • Opening the chest in the center
  • Using cardiopulmonary bypass
  • Connecting the right ventricle to the aorta so all the blood from the heart will be delivered to the aorta and thus the body
  • Enlarging the aorta
  • Adding a tube to make a path of blood to the lungs (systemic to pulmonary shunt)
  • Removing the wall between the atria

In some cases, such as low birth weight, prematurity or multiple medical problems, an alternative procedure called a hybrid procedure is used.

A bidirectional Glenn shunt is usually performed when a baby is three to eight months old. The procedure directs the blood flow from the upper body veins directly to the lungs.

A Fontan procedure is performed once the baby is few years old and the vessels of the lungs are mature enough for the surgery. The procedure connects the inferior vena cava to the pulmonary artery. This allows oxygen poor blood to flow to the lungs and the single ventricle to pump oxygen-rich blood to the body.