Diagnosis

Your baby's doctor will listen to your or your baby's lungs to assess his or her breathing and the possibility of fluid in the lungs. The doctor will listen to your or your baby's heart to determine if there are irregular heartbeats (arrhythmia) or an abnormal sound caused by turbulent blood flow (heart murmur).

For babies with truncus arteriosus, much of their medical care is provided by a pediatric cardiologist along with a pediatric cardiac surgeon and often a team of specialized staff. For adults with truncus arteriosus, much of their medical care is provided by an adult congenital cardiologist along with a congenital cardiac surgeon and often a whole team of specialized staff.

For the pediatric or adult congenital cardiologist to check the condition of your or your baby's heart and make a diagnosis, he or she will order one or more tests:

• Echocardiogram. An echocardiogram shows the structure and function of the heart. A transducer that emits sound waves is moved across the skin over the heart. The sound waves echo off internal structures, producing images on a monitor.

  In a baby with truncus arteriosus, the echocardiogram reveals the single large vessel leading from the heart, a hole in the wall between the left and right ventricles, and abnormalities in the valve between the large vessel and the ventricles. The test can also show how much blood is flowing to your baby's lungs, and whether there's a risk of high blood pressure in the lungs.

• X-ray. An X-ray uses radiation to produce still images of internal organs and structures. A chest X-ray can show the size of the heart, abnormalities in the lungs and excess fluid in the lungs.