Diagnosis

Some congenital heart defects are diagnosed before birth, while the baby is still in the womb. Signs of certain heart defects can be seen on a fetal ultrasound, a routine prenatal test used to check a baby's growth and development during pregnancy.

After birth, diagnosis of a congenital heart defect may occur if your child appears blue, has abnormal growth or your child's doctor hears an abnormal heart sound (murmur) while listening to your child's heart with a stethoscope.

Most heart murmurs are innocent, meaning that there is no heart defect and the murmur isn't dangerous to your child's health. However, some murmurs may be caused by abnormal blood flow to and from the heart.

Tests

Tests to diagnose a congenital heart defect include:

• Pulse oximetry. This noninvasive, painless test measures how much oxygen is in your child's blood. A sensor placed on the child's fingertip records the amount of oxygen in your child's blood. Too little oxygen may mean your child has a heart or lung problem.
• Electrocardiogram (ECG or EKG). This noninvasive test records the electrical activity of your child's heart. It can help diagnose heart defects or heart rhythm disorders. Sticky patches with sensors (electrodes) are placed on your baby's chest. Wires connect the patches to a computer, which displays results.
• Echocardiogram. An echocardiogram uses sound waves (ultrasound) to create images of you or your child's heart in motion. An echocardiogram allows the doctor to see the heart valves and heart muscle. If an echocardiogram is done on a baby before birth, it's called a fetal echocardiogram.
• Chest X-ray. Your child may have a chest X-ray to see if the heart is enlarged, or if the lungs contain extra blood or other fluid. These could be signs of heart failure.
• Cardiac catheterization. In this test, a thin, flexible tube (catheter) is inserted into a blood vessel, usually in the groin area, and guided to the heart. Catheterization can give your child's doctor more detailed information on heart function and blood flow. Certain heart treatments can be done during cardiac catheterization.
• Heart magnetic resonance imaging (MRI). A heart MRI is an increasingly common way to diagnose and evaluate congenital heart defects in adolescents and adults. A heart MRI creates 3D pictures of the heart, which allows for accurate measurement of the heart chambers.