Single ventricle defects

The exam

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

Your Children’s Hospital Boston cardiologist will also investigate whether he has a heart murmur—a noise heard through the stethoscope that’s caused by the turbulence of blood flow. The location in the chest where the murmur is best heard, as well as the sound and character of the murmur itself, will give the cardiologist an initial idea of the kind of heart problem your baby may have.
 

The tests

Some combination (not necessarily all) of the following medical tests will also used to diagnose your child’s single ventricle defect:

• electrocardiogram (EKG): An EKG is used to evaluate the electrical activity of your child’s heart. An EKG is usually the initial test for evaluating the causes of symptoms and detecting heart abnormalities, including single ventricle defects. It is 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.
   
• cardiac ultrasound (echocardiogram): An echocardiogram 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. If your baby has a single ventricle defect, the ultrasound will reveal the absence of a tricuspid or mitral valve and an underdeveloped ventricle. No discomfort is involved. It takes 30-60 minutes.

 A tiny patient gets an ultrasound at Children’s

If, during your pregnancy, a routine prenatal ultrasound or other signs cause your obstetrician to suspect 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—focusing exclusively on the baby’s heart—can usually detect whether a congenital heart defect is present.

• cardiac magnetic resonance imaging (cardiac MRI): An MRI is a non-invasive test using 3-D imaging technology produced by magnets to accurately determine the blood flow and functioning of your child’s heart. No pain is involved, although an IV may be needed. It takes about an hour.
   
• 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 the presence of a single ventricle defect. It takes a few moments. There is no pain or discomfort.
   
• cardiac catheterization: This invasive procedure performed under sedation provides detailed visual information and measurements about the structures 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.