Children's Hospital Colorado

Cardiac Tests and Procedures

We are one of the largest programs in the country treating patients with heart problems from before birth through adulthood, with exceptional outcomes.

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Doctors use different cardiac tests and procedures to diagnose, monitor and treat patients with congenital and childhood heart conditions. Some heart tests are often used on an ongoing basis in follow-up care and serve as a foundation for the excellent heart care provided at Children's Hospital Colorado’s nationally ranked Heart Institute.

As a cardiac patient, you or your child will undoubtedly experience one or more heart tests. Take some of the worry out of your child's heart tests by learning more about each test and what you can expect.

Chest X-ray

A pediatric chest X-ray is a non-invasive procedure that provides a picture of a child's heart, lungs and bones in the chest. It shows the location, size and shape of the heart, lungs and blood vessels. It can also show a doctor if there is fluid in the lungs.

A chest X-ray is useful for diagnosing pneumonia, tumors, a collapsed lung, congestive heart failure and rib fractures. It does not show any of the inside structures of the heart.

Cardiac catheterization 

A heart cath is a minimally invasive procedure that gives doctors a better understanding of how each unique heart works by visualizing the heart chambers, arteries and veins. Children’s Colorado performs diagnostic and procedural heart catheterizations for patients as young as 3 days old all the way through adulthood for patients with adult congenital heart disease. Read more about cardiac catheterization

Cardiac MRI and CT scan  

A cardiac MRI is a test that uses a magnet to produce signals from the atoms within the body and then turns these signals into pictures of the body. A CT scan is a painless test that shows detailed images of the heart’s internal structures. Learn more about how these tests help diagnose and monitor heart problems for kids at Children’s Colorado.


An echocardiogram (ECHO) is a non-invasive test that uses sound waves to create images of the heart. This test helps doctors learn about the structure and blood flow of the heart, and it can show critical heart defects and structural or valve abnormalities in children of all ages. Our team of heart imaging specialists can find out more about your child’s heart by using tests like ECHO, fetal echocardiogram (fetal ECHO), three-dimensional imaging (3D ECHO) and transesophageal echocardiogram (TEE). Read more about heart ECHOs.

Electrocardiogram (EKG), Holter monitor and Zio monitor 

A pediatric electrocardiogram (EKG), Holter monitor, Zio monitor and event recorder are tests that record the heart’s electrical activity in or out of the hospital. Read more about how we monitor heart activity with EKGs and Holter and Zio monitors.

Electrophysiology study

An electrophysiology (EP) study is done in the Electrophysiology Lab to give more detailed information about the heart's electrical activity. Performed by specialists called cardiac electrophysiologists, an EP study allows them to see the electrical activity in the heart and treat problems called cardiac arrhythmias. Read more about EP studies.

Exercise test

Exercise testing is an important evaluation to understand the limitations of patients with congenital or acquired heart or lung disease. The laboratory also tests young athletes who may have problems during exercise to better understand any heart or lung conditions they might have. Cardiologists perform other tests when the patient is not moving, while exercise testing can help predict how a child will respond to the demands of exercise. 

Exercise testing can be used to evaluate: 

  • Effects of surgery, catheterization or other treatments on your child’s heart function 
  • Capacity of the heart and lungs 
  • Symptoms your child might have during exercise, such as chest pain, fainting or asthma 

Lab tests

Laboratory testing, such as blood, sweat and glucose tolerance tests, can provide a closer look at the body's functions and processes. Read more about lab tests.

Pacemakers, Defibrillators and Devices 

Cardiac implantable electronic devices are placed in a patient during surgery or minimally invasive procedure to regulate their heart rhythm. Learn about the process of implanting a pacemaker and cardioverter defibrillators (ICDs) at Children’s Colorado

Tissue biopsies

A heart tissue biopsy is a test in which a small piece of the heart muscle is taken to be looked at under a microscope. One of the most common reasons your child’s doctor might recommend a heart biopsy is to see if a virus is affecting the heart, causing inflammation of the heart muscle (a condition called myocarditis).

A doctor may also order a heart biopsy if your child has signs of a heart muscle disorder (known as cardiomyopathy). A heart tissue biopsy is also routinely done after a heart transplant to monitor for possible signs of the body rejecting a new heart.