Glossary of Terms

This glossary of terms has been compiled for your reference. Select the first letter of the word you’re searching for to begin.

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Calcium Antagonists (Calcium Channel Blockers)

A class of drugs used to treat high blood pressure and some other heart conditions. They can slow the heart rate and relax blood vessels.


Microscopically small blood vessels between arteries and veins that distribute oxygenated blood to the body’s tissues.


Pertaining to the heart.

Cardiac Arrest

The stopping of the heartbeat, usually because of interference with the electrical signal (often associated with coronary heart disease).

Cardiac Catheterization

The process of examining the heart by introducing a thin tube (catheter) into a vein or artery and passing it into the heart.

Cardiac Computed Tomography (CT), Computerized Axial Tomographic Scan (CAT scan)

An X-ray imaging technique that provides cross-sectional images of the chest, including the heart and great vessels, or the brain. It’s used to evaluate certain heart diseases and define the areas affected by stroke.

Cardiac Positron Emission Tomography (PET)

A test that lets physicians study and quantify how the heart tissue works. PET combines tomographic imaging with radionuclide tracers and tracer kinetic principles.


The study of the heart and its functions in health and disease.


A serious disease affecting the heart. It involves an inflammation and reduced function in heart muscle. There are multiple causes including viral infections.

Cardiopulmonary Resuscitation (CPR)

A combination of chest compression and mouth-to-mouth breathing. This technique is used during cardiac arrest to keep oxygenated blood flowing to the heart muscle and brain until advanced cardiac life support can be started or an adequate heartbeat resumes.


Pertaining to the heart and blood vessels. (“Cardio” means heart; “vascular” means blood vessels.) The circulatory system of the heart and blood vessels is the cardiovascular system.

Carotid Artery

One type of major artery in the neck carrying blood from the heart to the brain. The other type is vertebral artery.

Carotid Artery Disease (Carotid Artery Stenosis)

A carotid artery narrowed by a buildup of plaque. A type of atherosclerosis. Carotid artery disease is a major risk factor for ischemic stroke.


A fat-like substance found in the blood and produced by the liver. Also found in animal tissue and present only in foods from animal sources such as wholemilk dairy products, meat, fish, poultry, animal fats and egg yolks.


Fatty particles in the blood containing mainly triglycerides, but also cholesterol, phospholipids and protein. They’re made in the intestinal wall as foods are digested.

Circulatory System

Pertaining to the heart, blood vessels and the blood’s circulation.

Coarctation of the Aorta (“Coarct”)

A congenital heart defect in which the aorta is pinched or constricted. This obstructs blood flow to the lower part of the body and increases blood pressure above the constriction.

Collateral Circulation

The process in which a system of small, normally closed arteries opens up and starts to carry blood to part of the heart when a coronary artery is blocked, or to part of the brain when a cerebral artery is blocked. They can serve as alternate routes of blood supply.


Refers to conditions existing at birth.

Congenital Heart and Blood Vessel Defects (Congenital Cardiovascular Defects, Congenital Cardiovascular Disease)

Malformation of the heart or its major blood vessels present at birth.

Congestive Heart Failure

The inability of the heart to pump out all the blood that returns to it. This results in blood backing up in the veins that lead to the heart and sometimes in fluid accumulating in various parts of the body.

Coronary Arteries

Two arteries arising from the aorta that arch down over the top of the heart, branch and provide blood to the heart muscle.

Coronary Artery Disease (CAD)

Conditions that cause narrowing of the coronary arteries, reducing blood flow to the heart muscle. A type of atherosclerosis.

Coronary Bypass Surgery

Surgery that reroutes, or “bypasses,” blood around clogged coronary arteries and improves the supply of blood and oxygen to the heart muscle. It’s sometimes called CABG (for coronary artery bypass graft) or “cabbage.”

Coronary Care Unit (CCU)

A specialized facility in a hospital or emergency mobile unit that’s equipped with monitoring devices and staffed with trained personnel. It’s designed specifically to treat heart patients.

Coronary Heart Disease (CHD)

Disease of the heart caused by atherosclerotic narrowing of the coronary arteries likely to produce angina pectoris or heart attack.

Coronary Occlusion

An obstruction of a coronary artery that hinders blood flow to some part of the heart muscle. A cause of heart attack.

Coronary Thrombosis

Formation of a clot in one of the arteries that conduct blood to the heart muscle. Also called coronary occlusion.

Creatine Kinase (CK)

A blood enzyme. Tests for CK and the fraction CK-MB are used to confirm the existence of heart muscle damage.


Blueness of skin caused by insufficient oxygen in the blood.