Narrator: This is Science Today. Hypoplastic left heart syndrome is a congenital heart defect which strikes one in a few thousand babies each year in this country. According to Dr. Wayne Tworetzky of the University of California, San Francisco, no one knows why babies develop this, but the defect is devastating, since it affects the heart's left ventricle, which is the main pumping chamber.
Tworetzky: It pumps blood to your brain, your kidneys, your liver and in this condition either all or one of the parts of the left side of the heart are underdeveloped so you either have a small pumping chamber or ventricle or small, very small aortic valve, so blood can not flow normally through the left side of the heart.
Narrator: Twortezky found a prenatal diagnosis of this defect can increase a newborn's survival rate, since treatment can begin immediately following birth.
Tworetzky: In our study, all of the children had a prenatal diagnosis survived to go home after the first surgery and in the group that were diagnosed after birth, about sixty-five percent of them survived. So there is a large difference.
Narrator: For Science Today, I'm Larissa Branin.