Diagnostic Tests

In order to find out what’s going on with your child’s heart as quickly as we can, our cardiologists will recommend various diagnostic tests. Because the sooner we can get to the bottom of your child’s heart problem and get treatment started (if needed), the better.

At the Nemours Cardiac Center, located in the Nemours/Alfred I. duPont Hospital for Children (AIDHC), our patients can get any kind of diagnostic cardiac test, right on-site. Our cardiologists from the Center also travel throughout the Delaware Valley to evaluate and follow up with kids at various Nemours clinics and partner health providers. At these other convenient locations, our doctors refer kids to come to AIDHC or other recommended facilities for more testing, if necessary.

In Florida, our Nemours cardiologists evaluate and manage the care of young patients in Pensacola and Destin – referring them to other partner and recommended facilities for any tests that aren’t available in our clinics.

Wherever your child is seen by our expert cardiologists, one or more of the following tests may be recommended or ordered during the initial visit:

• Electrocardiogram (or EKG), which measures the heart’s electrical activity and isn’t painful at all. A series of electrodes (small metal tabs) are simply fixed to your child’s skin in a few locations with tiny sticky papers. Then the information obtained about the electrical activity of your child’s heart is transferred to a computer, where it’s then stored and printed as a graph.
• Holter monitor – an EKG done over a long period of time, usually 24 hours or more. The electrodes are connected to the chest and the wires are attached to a portable EKG recorder. The child is encouraged to continue normal daily activities, but must be careful to not get the electrodes wet (for example, no swimming, showering, or activities that cause a lot of sweating). There are two kinds of Holter monitoring: continuous recording (when the EKG is on throughout the entire monitoring period) and event monitoring (when data is recorded only when the child feels symptoms and then turns the Holter monitor on).
• Telephonic monitor – used to help doctors diagnose a heart rhythm problem. This kind of device is worn by your child and transmits the information from the EKG to your child’s doctor over the telephone.

Another test the doctors may order is a cardiopulmonary exercise assessment (also called just an “exercise test” or a “stress test”). While attached to an EKG machine, your child’s heart rate and rhythm are measured while exercising – by doing things like riding a stationary bicycle or walking on a treadmill under supervision. If your child has or might have a heart problem or has undergone heart surgery, you’ll want to know what kinds of physical activities are OK – and which ones aren’t. It can also pick up abnormalities in the heart’s rhythm that aren’t obvious during rest.

Imaging Tests

To evaluate your child’s heart structure and function we use advanced imaging (also called “medical imaging”) tests at the Cardiac Center. Our sophisticated equipment lets us produce precise diagnostic images of the heart so we can create the very best treatment plan for your child.

The most frequently used imaging tool is echocardiography (or “echo,” for short) – a specialized form of ultrasound that builds a picture of the heart using sound waves. The Echocardiography Department within the Cardiac Center received a three-year accreditation for pediatric transthoracic echocardiography by the Intersocietal Commission for the Accreditation of Echocardiography Laboratories (ICAEL) -- the country’s highest level of achievement in the specialty.

Four types of echocardiography are available at the Nemours Cardiac Center:

• Transthoracic echocardiography painlessly produces images of your child’s heart from the surface of the chest and upper abdomen. Often, these images are so precise that invasive testing (inserting an instrument into the body) isn’t needed – making it an ideal way to diagnose a heart problem and monitor changes in the heart as your child grows. These studies can be performed with ease in both the inpatient and outpatient settings. We now also offer 3-D echocardiography, which allows us to visualize the structure of the heart valves and other heart structures in even greater detail.
• Transesophageal echocardiography (TEE) is done by inserting a small ultrasound probe into the mouth and through the esophagus (the food pipe that connects the throat with the stomach and lies directly behind the heart). This is often used for older, larger children (giving the best close-up view of some otherwise hidden regions of the heart) and is extremely useful for obtaining images during surgery and cardiac catheterization.
• Fetal echocardiography is an in-depth ultrasound study used to view the structure, function, and rhythm of a baby’s heart while in utero (still in the mother’s womb during pregnancy) – and as early as the 18th week of gestation.
• Intravascular echocardiography (ICE) is sometimes done during cardiac catheterization by inserting a thin plastic, flexible tube (called a “catheter”) with a tiny ultrasound probe at the tip through the blood vessels. This ultrasound catheter is advanced to the heart to take a close look at defects and guide treatment during a cardiac catheterization procedure.

Each method provides its own special “window” into your child’s heart. Each heart chamber, heart valve, artery, and vein associated with the heart (even tiny structures such as the coronary arteries) is examined. Normal and abnormal blood flow patterns can be detected using a special kind of ultrasound, which demonstrates the flow patterns as variations of color and shape.

Your child’s doctors may also order one or both of these other imaging tests:

• Cardiac magnetic resonance imaging (MRI) – an extremely helpful, safe imaging tool that doesn’t require inserting anything into the body. An MRI produces strikingly clear, complete pictures of the heart and blood vessels that connect to the heart. A cardiac MRI allows doctors to analyze the structure and function of the heart, as well as the area surrounding the heart (that are less visible with other diagnostic tools) – specifically the lungs, airways, and the esophagus. Because kids must be completely still for MRI, sedation or anesthesia may be required.
• Cardiovascular computed tomography (CT). By injecting a small amount of contrast agent (or dye) into your child’s circulation, which is a safe technique, the doctor can get an accurate image of the important blood vessels attached to the heart and identify any abnormalities (in the heart and other structures in the chest such as the lungs and airways) in a matter of seconds. The latest technology rapidly produces pictures of many layers of the heart. And because CTs don’t take very long at all, some smaller children can be evaluated for potential problems without having to be sedated.

Depending on what these tests reveal, the team may schedule further evaluation that may include the following:

• Myocardial perfusion scan (used to look at blood flow to the heart muscle during rest and stress)
• Lung perfusion scan (used to look at blood flow distribution to the right and left lung)
• Tilt-table testing (a way to look for a cause of fainting – by monitoring the child’s blood pressure and the heart’s electrical activity on an EKG as the child is attached to a table that moves)
• Cardiac catheterization and angiography (evaluating the blood vessels through a diagnostic cardiac catheterization – a completely painless test, performed under sedation with local or general anesthesia, that’s done by inserting a catheter into an artery and vein that lead to the heart, and advancing it to the heart  to take measurements and pictures with X-ray)
• Transesophageal or intravascular electrophysiologic study (studying the heart rhythm through a catheter placed in the esophagus or in a blood vessel near the heart)
• implantation of an arrhythmia detecting device (placing a device that can pick up abnormal heart rhythms)