Hypoplastic left heart syndrome

HLHS is a lethal cardiac defect consisting a severely underdeveloped left heart ventricle as a result of heart valve maldevelopment and blockage. The right ventricle is enlarged an an intra-atrial septum defect is usually present. Death usually occurs within the first weeks of life. Heart transplant has been tried.

There is great variability in the recorded rates of HLHS around the world, but generally they are less than 1 : 20,000 births.