Hypoplastic left heart syndrome is a heart problem that is present at birth (congenital) in which the left side of the heart and aorta are very small or underdeveloped. The small left ventricle makes the right ventricle responsible for pumping blood to the lungs and body. Too little blood and oxygen may be pumped to the body.

A series of heart surgeries may be done to repair this problem and help the heart work better.