How Is Tetralogy of Fallot Diagnosed?

Doctors perform a physical exam on the baby and order medical tests to diagnose tetralogy of Fallot. The signs and symptoms usually appear during the first weeks of life. Your infant's doctor may see the 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

Doctors who specialize in heart problems are called cardiologists. Pediatric cardiologists take care of babies and children who have heart problems. Other specialists who treat heart defects include cardiac surgeons (doctors who repair heart defects using surgery).

Physical Exam

During the physical exam, the doctor:

• Listens to your baby's heart and lungs with a stethoscope.
• Looks for signs and symptoms, such as bluish color of skin and lips and rapid breathing.
• Looks at general appearance. Some children with tetralogy of Fallot have a characteristic facial appearance because they have DiGeorge syndrome.

Diagnostic Tests and Procedures

The doctor will order several tests to diagnose tetralogy of Fallot. These tests will help the doctor determine the exact nature of the defects and how serious they are.

Echocardiogram

This test, which is harmless and painless, uses sound waves to create a moving picture of the heart. During an echocardiogram, ultrasound waves bounce off the structures of the heart. A computer converts the sound waves into pictures on a video screen. The test allows the doctor to clearly see any problem with the way the heart is formed or the way it’s working.

An echocardiogram is an important test for diagnosing tetralogy of Fallot because it shows the four problems with the heart’s structure and how the heart is reacting to these problems. This test helps the cardiologist decide the best time to repair these defects and what type of surgery is needed. Echocardiograms also are used to check a child’s condition over time, after the defect has been repaired.

EKG (Electrocardiogram)

An EKG detects and records the electrical activity of the heart. This simple and painless test is used to assess the heart rhythm. An EKG shows how fast the heart is beating and whether the heart’s rhythm is steady or irregular. This test also can help determine whether the right ventricle is enlarged (ventricular hypertrophy).

Chest X Ray

A chest x ray takes a picture of the heart and lungs. It can show whether the heart is enlarged or whether the lungs have extra blood flow or extra fluid, which can be a sign of heart failure.

Pulse Oximetry

Pulse oximetry shows how much oxygen is in the blood. A sensor is placed on the fingertip or toe (like an adhesive bandage). The sensor is attached to a small computer unit that displays a number that tells 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. A dye that can be seen on an x ray is injected through the catheter into a blood vessel or a chamber of the heart. This allows the doctor to see the flow of blood through the heart and blood vessels on the x-ray image.

Cardiac catheterization also can be used to measure the pressure inside the heart chambers and blood vessels. It can determine whether blood is mixing between the two sides of the heart.