What is wrong with my baby’s heart, and what problems does the defect cause?

A congenital heart defect is a birth defect of the heart. Many different types of defects exist. The most common type of defect is a hole in either the upper or lower wall of the heart. Both of these defects result in an excess amount of blood flow to the lungs. Other defects include abnormalities with the heart valves, resulting in the heart muscle having to work harder than normal to pump blood to the lungs or body.