Most cases of single ventricle defects happen in the developing heart during early pregnancy. Some might be due to a combination of genes and things in the baby's and mother's environment during this early stage.
How Is a Single Ventricle Defect Diagnosed?
Single ventricle defects are diagnosed either during pregnancy by a fetal echocardiogram ("echo") or shortly after birth with an echocardiogram. An echo is a completely safe and painless test that uses ultrasound (sound waves) to build a series of pictures of the heart.
Babies born with a single ventricle defect that wasn't found before birth may become very ill. The exact symptoms will depend on the defect causing the single ventricle.
How Is a Single Ventricle Defect Treated?
Single ventricle defects are treated by two or three surgeries. The first surgery varies, depending on the diagnosis. But the second and third surgeries are usually the same no matter what kind of heart defect a child has.
The goal of the surgeries is to rebuild the heart and make sure that it:
pumps blood out to the body
returns the blood to the lungs (without being pumped by the heart as it would be in a child with two normal ventricles)
Other procedures may be needed, depending on a child's diagnosis. But by the time children have the Fontan procedure, they will have similar medical care, challenges, and potential complications.
Most children who have had a single ventricle heart repaired are on medicines for the rest of their lives. Some who had the Fontan operation can exercise normally, but many will have limits on how active they can be.