Truncus Arteriosus

At Children’s Hospital Boston, we understand that the first step in treating your child is forming an accurate, complete and timely diagnosis.

The exam

If your newborn baby was born with a bluish tint to her skin, or if your young child is experiencing certain symptoms, your pediatrician will immediately refer you to a pediatric cardiologist (and/or neonatologist), who will perform a physical exam. Your child’s doctor will listen to your baby’s heart and lungs, measure the oxygen level in her blood (non-invasively) and make other observations that help to determine the diagnosis.

Your child’s cardiologist will also investigate whether she has a heart murmur—a noise heard through the stethoscope that’s caused by the turbulence of blood flow. If there’s a murmur, the location in the chest where the murmur is best heard, as well as the sound and character of the murmur itself, gives the cardiologist a better sense of the kind of heart problem your baby may have.

Note: If your child’s truncus arteriosus was detected prenatally through ultrasound, upon birth she’ll be immediately admitted for stabilization and surgery.

The tests

Some or all of the following tests may be used to confirm a diagnosis of truncus arteriosus and its related defects, and to provide detailed information on the shape and condition of your baby’s heart:

• echocardiogram (cardiac ultrasound): An echocardiogram is the chief diagnostic test for truncus arteriosus. It evaluates the structure and function of your child’s heart using electronically recorded sound waves that produce a moving picture of the heart and heart valves. This test can reveal the single vessel (truncus arteriosus), the ventricular septal defect (VSD) and any regurgitation from the truncal valve. No discomfort is involved. It takes 30-60 minutes.

Note: If, during your pregnancy, a routine prenatal ultrasound or other signs raise your obstetrician’s suspicion of a congenital heart defect in the fetus, a cardiac ultrasound (described in the paragraph above) of the baby in utero will usually be the next step. The cardiac ultrasound (fetal echocardiogram)—focusing exclusively on the baby’s heart—can detect many congenital heart defects.

• chest x-ray: A conventional chest x-ray will evaluate the size and spatial relationships of the heart within the child’s chest, as well as any abnormalities or excess fluid in the lungs. It takes a few moments. There is no pain or discomfort.
• electrocardiogram (EKG): An EKG evaluates the electrical activity of your child’s heart. It helps to evaluate the causes of symptoms and to detect heart abnormalities, including truncus arteriosus. It’s performed by placing electrodes on the arms, legs and chest to record the electrical activity. The test takes five minutes or less and involves no pain or discomfort.

Tests to monitor the condition of the truncal (aortic) valve and the conduit repair over time can include:

• cardiac catheterization: provides detailed visual information and measurements about the structures and pressures inside the heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as the pulmonary artery and aorta.
  Catheterization can also be used in an intervention later on—for instance, to address an obstruction of the conduit that might have developed, or a valve that has started leaking.
• cardiac magnetic resonance imaging(MRI): provides a picture of the heart and blood vessels, but without using x-rays. MRI is rarely used in babies with truncus arteriosus, but may be helpful in follow-up to surgery to detect complications.