The Heart Institute

Hypoplastic Left Heart Syndrome (HLHS)

HLHS is a severe congenital heart defect in which the left side of the heart does not develop during pregnancy. This means the left ventricle (the pumping chamber that sends blood to the body) and the aorta (the main artery that carries the blood to the body) and the mitral and aortic valves are very small and cannot support life.

Surgical repair requires three stages to enable the single working chamber to do the work of two ventricles. The first stage, the Norwood I procedure is typically performed within the first 2 weeks of life. The second stage, the bi-directional Glenn, is typically performed before the infant is 6 months old. At two to three years old, the third, and final stage – the Fontan operation is completed.

Rarely, the staged approach cannot be performed on an HLHS heart, and a Heart Transplant is performed.

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