How Is Tetralogy of Fallot Diagnosed?

Doctors diagnose tetralogy of Fallot based on a baby’s signs and symptoms, a physical exam, and the results from tests and procedures.

Signs and symptoms of the heart defect usually occur during the first weeks of life. Your infant's doctor may notice signs or symptoms during a routine checkup. Some parents also notice cyanosis (a bluish tint to the skin, lips, and fingernails) or poor feeding and bring the baby to the doctor.

Specialists Involved

If your child has tetralogy of Fallot, a pediatric cardiologist and cardiac surgeon may be involved in his or her care.

A pediatric cardiologist is a doctor who specializes in diagnosing and treating heart problems in children. Cardiac surgeons repair heart defects using surgery.

Physical Exam

During a physical exam, the doctor may:

• Listen to your baby's heart and lungs with a stethoscope.
• Look for signs and symptoms, such as a bluish tint to the skin, lips, or fingernails and rapid breathing.
• Look at your baby’s general appearance. Some children who have tetralogy of Fallot have characteristic facial traits because they have DiGeorge syndrome.

Diagnostic Tests and Procedures

Your child’s doctor may recommend several tests to diagnose tetralogy of Fallot. These tests can provide information about the four heart defects that occur in tetralogy of Fallot and how serious they are.

Echocardiography

Echocardiography (echo) is a painless test that uses sound waves to create a moving picture of the heart. During the test, the sound waves (called ultrasound) bounce off the structures of the heart. A computer converts the sound waves into pictures on a screen.

Echo allows the doctor to clearly see any problem with the way the heart is formed or the way it's working.

Echo is an important test for diagnosing tetralogy of Fallot because it shows the four heart defects and how the heart is responding to them. This test helps the cardiologist decide when to repair these defects and what type of surgery is needed.

Echo also is used to check a child's condition over time, after the defects have been repaired.

EKG (Electrocardiogram)

An EKG is a simple, painless test that records the heart’s electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). It also records the strength and timing of electrical signals as they pass through each part of the heart.

An EKG also can help the doctor determine whether the right ventricle is enlarged (ventricular hypertrophy).

Chest X Ray

A chest x ray is a painless test that creates pictures of the structures in the chest, such as the heart and lungs. This test can show whether the heart is enlarged or whether the lungs have extra blood flow or extra fluid, a sign of heart failure.

Pulse Oximetry

For this test, a small sensor is attached to a finger or toe (like an adhesive bandage). The sensor gives an estimate of how much oxygen is in the blood.

Cardiac Catheterization

During cardiac catheterization (KATH-e-ter-i-ZA-shun), a thin, flexible tube called a catheter is put into a vein in the arm, groin (upper thigh), or neck and threaded to the heart.

Special dye is injected through the catheter into a blood vessel or a chamber of the heart. The dye allows the doctor to see the flow of blood through the heart and blood vessels on an x-ray image.

The doctor also can use cardiac catheterization to measure the pressure and oxygen level inside the heart chambers and blood vessels. This can help the doctor determine whether blood is mixing between the two sides of the heart.