Hypoplastic Left Heart Syndrome  (HLHS)

What is hypoplastic left heart syndrome?

Hypoplastic left heart syndrome (HLHS) occurs when the left side of a baby’s heart does not develop correctly. It is a congenital heart condition. This means it’s a condition that develops before a baby is born.

Although HLHS can take many forms, babies born with HLHS usually have a few problems with the left side of their hearts. These can include:

• The left ventricle is too small. The left ventricle is the lower chamber of the heart that pumps blood from the heart to the rest of the body. When it’s small, the left ventricle can’t get enough blood to the body.
• The mitral valve is too small or is closed. The mitral valve separates the left ventricle from the left atria, which is the upper left heart chamber.
• The aortic valve is small or closed. This is the valve between the left ventricle and the aorta, the artery that brings blood to the rest of the body.
• The opening of the aorta is very small.

Together, these problems make it very hard for the heart to pump enough blood and oxygen to the body. This is why babies with HLHS usually need treatment shortly after birth. 

What are the signs and symptoms of HLHS?

In some cases, HLHS is diagnosed during pregnancy with a fetal echocardiogram. After a baby is born, the symptoms of HLHS are usually noticeable shortly after birth. They may include:

• Rapid breathing
• Shortness of breath or trouble breathing
• Poor feeding
• A bluish tint to the skin, lips and nails

What causes HLHS?

Experts do not know what causes HLHS. Although some babies with HLHS have a history of congenital heart disease in their families, most do not.

How is HLHS treated?

Most babies with HLHS need surgery shortly after birth. Your care team at Arkansas Children’s is experienced in treating all forms of HLHS and will work with you to come up with the best treatment option for your child. Treatments may include: 

• Ductal Stent - Interventional procedures such as ductal stent placement (Hybrid approach) or medical palliation along with surgical placement of pulmonary artery bands may be indicated to stabilize the amount or direction of blood flow to the lungs and the body. These procedures are performed in the Cardiac Surgery Operating Room or Cardiac Catheterization Lab. 
• Norwood Procedure - Traditional surgical palliation (the Norwood procedure) is routinely performed sometime in the first week of life. The primary goal of this surgery is to convert the heart into a single pumping chamber and to create a stable pathway for blood to get to the lungs. This will be the first stage of a progression of surgeries (usually, three surgeries over the first five years of life are needed). Each surgery will be specific to the child’s anatomy and planned out thoroughly by the pediatric cardiology and cardiothoracic surgery team. The overall goal of these surgeries is to set up a “single ventricle” (the right heart) as the main pumping chamber of blood circulation while pulmonary blood (blood to the lungs) drains back passively. As the child grows, they will require a series of tests/exams to evaluate for “candidacy” of progression down this pathway.
• Glenn Procedure - The second palliation, the Glenn, is typically performed sometime around 3 – 6 months of age. 
• Fontan Procedure - The final palliation, a Fontan, is undertaken after the child is 2 – 3 years old. However, some children may be delayed until older. 

Your care provider will provide an individualized care plan to each patient due to the complexity and wide range of recovery for each of the surgeries.