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Heart Center Glossary


The world of medicine is full of unfamiliar words and terminology. Not understanding what's being said can seem overwhelming, especially when it relates to you and your child's needs.

That's why there is a special glossary of terms, terms you may hear from your team of doctors and other specialists at The Heart Center.

Cardiopulmonary (Heart-Lung) Bypass Machine

Used during open-heart surgery, this device performs the work of the heart and lungs by pumping and oxygenating the blood. This allows the heart to be motionless during the surgery.


The procedure of inserting small tubes called catheters into the heart; used for diagnostic and intervention purposes. More than 800 procedures are performed in two state-of-the-art cardiac catheterization labs at Children's.

CT or CAT Scan

Computerized tomography scan. A non-invasive procedure that takes cross-sectional images of the heart or other internal organs to detect any abnormalities that may not show up on an ordinary X-ray.

Extracorporeal Membrane Oxygenation (ECMO)

A special procedure that utilizes an artificial heart-lung machine, like the cardiopulmonary bypass equipment used during open-heart surgery. ECMO also performs the work of the heart and lungs.

Echocardiogram (ECHO)

A procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor which produce a moving picture of the heart and heart valves. One of the most widely used non-invasive tests for diagnosing heart disease.

Electrocardiogram (EKG)

A recording of the heart's electrical activity that provides information about heart rate, heart rhythm and abnormalities of the heart's structure. It is also used to evaluate many forms of heart disease.


Diagnosis and treatment of disorders of the heart's electrical system.

Fetal Echocardiogram

See "Echocardiogram" above. This fetal examination is conducted on expectant mothers using high-frequency sound waves to look at the heart and major blood vessels of the fetus.

Fontan Procedure

An operation used to treat complex birth defects of the heart like hypoplastic left heart syndrome (HLHS). Allows the oxygen-poor (blue) blood returning to the heart to instead flow directly into the pulmonary artery, greatly improving the oxygenation of blood.

Hypertrophic Obstructive Cardiomyopathy (HOCM)

Also called asymmetrical septal hypertrophy (ASH), or idiopathic hypertrophic subaortic stenosis (IHSS); is an enlarged heart muscle that obstructs the blood flowing out of the heart.

Magnetic Resonance Imaging (MRI)

A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and bones within the body.


An electronic device that is surgically placed in the patient's body and connected to the heart to regulate the heartbeat. Temporary pacemakers are placed outside the body.


A small box with wires attached to EKG patches on the chest that sends information about the heartbeat via radio transmission to health care professionals for evaluation. This allows doctors to collect information about a patient's heart function without requiring the patient to be in the hospital.

Transesophageal Echocardiography (TEE)

A diagnostic test that uses a long tube guided through the mouth and throat, and into the esophagus to evaluate the structures inside the heart with sound waves.

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