Our glossary of heart health terms can help you understand the terminology your doctor uses — so you can have more meaningful discussions.



Key Takeaways


You’ll be able to more fully understand your doctor’s advice.


You’ll be more confident talking with your doctor using heart health terms.


If you don’t understand, feel free to ask your doctor to explain anything.

Doctors and cardiologists sometimes speak in terms that are hard to understand. Since your health is so important, you need to understand exactly what your doctor is saying, so there’s no confusion. Here’s a handy glossary of common heart health terminology.

Now you are armed with helpful definitions when you talk to your doctor.


AFib or Atrial Fib

(Short for atrial fibrillation.) This is an irregular heartbeat where the top two chambers of the heart (the atria) are not beating in a synchronized rhythm with the two bottom chambers (ventricles). Sometimes this condition produces dangerous blood clots that may enter the bloodstream and cause a stroke.


A bulging enlargement in an artery wall that can slowly develop over several years, causing an increased potential for bursting.


Chest pain due to an inadequate supply of oxygen to the heart muscle. The term angina is now used almost exclusively to denote angina pectoris, the medical term for chest pain or discomfort that is most often due to coronary heart disease.

Stable angina refers to episodes of chest discomfort that are usually predictable, and which occur on exertion or under mental or emotional stress. Unstable angina refers to episodes of chest discomfort that are unpredictable and usually occur while at rest.


A procedure with a balloon-tipped catheter to enlarge a narrowing in a coronary artery. Also known as PCTA (Percutaneous Transluminal Coronary Angioplasty) or PCI (Percutaneous Coronary Intervention).


  1. Counteracting high blood pressure.
  2. An agent that reduces high blood pressure.


An agent used to prevent or interfere with the formation of a thrombus (a blood clot in a blood vessel or within the heart).


Problems with the rate or rhythm of the heart, often treated with the installation of a pacemaker.


Commonly called clogged arteries, it is caused by progressive buildup of plaque that can obstruct blood flow in arteries or rupture and cause a clot, which can cause blockages. Smoking, high blood pressure, high levels of "bad" or LDL cholesterol, diabetes and family history all increase risk for clogged arteries.


Blood Clot

A mass formed from constituents of the blood within blood vessels.

Blood Pressure

The pressure of the blood on the walls of the arteries, produced primarily by contraction of the heart muscle.

Blood Pressure (Diastolic)

Diastolic blood pressure is the bottom number in your blood pressure reading, which is also the lower of the two numbers. It measures the pressure in the arteries when the heart muscle is resting (between beats) and refilling with blood.

Blood Pressure (Systolic)

Systolic blood pressure is the top number of your blood pressure reading, which is also the higher of the two numbers. It measures the pressure in the arteries when the heart muscle contracts (beats).

Blood Test (or Blood Work)

A sample of blood is taken (usually from your arm), and then analyzed to look for imbalances or signs of disease.

Blood Thinners

Medicines that help blood flow smoothly through the veins and arteries, and help keep blood clots from forming.

Body Mass Index (BMI)

An index for relating a person's body weight to his or her height. Check to see if you have a normal BMI.



Enlarged heart, usually due to high blood pressure causing the heart to pump harder which thickens the muscle.


A general diagnostic term for disease for the heart muscle (myocardium).


Pertaining to the heart and blood vessels throughout the entire body — relating to the circulatory system.

Carotid Endarterectomy

A surgical procedure designed to clean out material blocking the carotid artery, a major artery in the neck that supplies blood to the brain. The aim of the procedure is to restore normal blood flow to the brain, thereby helping to prevent a potential stroke.


Pertaining to the blood vessels of the cerebrum, or brain.


A fat-like substance that is a building block of the outer layer of cells (cell membranes). It is essential to the formation of bile acids, cell membranes, vitamin D and certain hormones. Cholesterol is not dissolved in the blood, but is transported in the bloodstream as water-soluble molecules known as lipoproteins. Lipoproteins are characterized by their density: high density lipoprotein (HDL) and low density lipoprotein (LDL).

Cholesterol (HDL)

HDL (high density lipoprotein) is the "good" cholesterol. High HDL levels reduce the risk for heart disease, but low levels increase the risk.

Cholesterol (LDL)

LDL (low density lipoprotein) is the "bad" cholesterol. Elevated LDL levels are associated with an increased risk of heart disease.

Cholesterol (Total)

Total cholesterol is defined as the sum of HDL, LDL and VLDL.

Congestive Heart Failure

Inability of the heart to pump blood with normal efficiency. When this happens, the heart is unable to supply enough blood to the body's other organs such as the brain, liver and kidneys. Symptoms can include shortness of breath, pooling of fluid in the legs and feet, and swelling and enlargement of the heart.

Coronary Artery Bypass Graft (CABG)

A surgical procedure whereby a new route is created around plaque within a coronary artery, using part of a vein or artery as a graft. The procedure permits increased blood flow to deliver oxygen and nutrients to the heart muscle.

Coronary Heart Disease (CHD)

A condition that begins when hard cholesterol substances (plaques) are deposited within a coronary artery. If the plaque ruptures, it can cause the formation of a clot, which can obstruct the flow of blood to the heart muscle, producing symptoms and signs of CHD that may include chest pain (angina), heart attack or sudden death due to a fatal disturbance of the heart rhythm. Also known as coronary artery disease (CAD).

C-Reactive Protein (CRP)

A plasma protein that increases in the blood in the presence of inflammation from certain conditions, including coronary heart disease.


Deep Vein Thrombosis (DVT)

A blood clot formed deep in the body (usually in legs or hips) which can break off and lodge in lungs or elsewhere.


When used alone, the term refers to diabetes mellitus, a group of metabolic diseases characterized by high blood sugar, resulting from defects in the secretion and/or action of insulin. It occurs in two major forms: type I (insulin-dependent) diabetes mellitus and type II (non-insulin-dependent) diabetes mellitus.


Electrocardiogram (ECG)

A recording of the electrical activity of the heart. It is a simple, non-invasive procedure whereby electrodes are placed on the skin of the chest and connected to a machine that measures the heart’s electrical activity. An example of its clinical use is in the initial diagnosis of a heart attack, which is usually made by a combination of clinical symptoms and characteristic ECG changes; the ECG can detect areas of muscle ischemia (muscle deprived of oxygen) and/or dead tissue in the heart.

Exercise (moderate)

Moderate physical activities that cause a slight increase in heart rate or breathing, such as raking leaves, mowing the lawn or heavy cleaning.

Exercise (vigorous)

Vigorous physical activities that cause heavy sweating or a large increase in breathing or heart rate for at least 10 minutes at a time. Some examples include running, lap swimming, aerobics classes or fast bicycling.


Gastrointestinal (GI) Bleed

An occurrence of bleeding in the gastrointestinal tract, which refers to the stomach and intestines.


HbA1c Test

An HbA1c test measures a person's average blood sugar control for an average of 3 months and provides diabetes patients with a better idea of how well their diabetes treatment plan is working.

Heart Attack

Death of the heart muscle due to the loss of blood supply, usually caused by a complete blockage of a coronary artery (one of the arteries that supplies blood to the heart muscle). Death of the heart muscle, in turn, causes chest pain and electrical instability of the heart muscle tissue. Also known as myocardial infarction (MI).

Heart Event

The exact definition of a heart event can vary, but refers to an event associated with the cardiovascular system, such as a heart attack (myocardial infarction).

High Blood Pressure

A repeatedly elevated blood pressure exceeding 140 over 90 mmHg — a systolic pressure above 140 with a diastolic pressure above 90. Also known as hypertension.

High Density Lipoprotein (HDL)

A fat-like substance that helps reprocess or remove LDL cholesterol from the body by transporting it to the liver. HDL is the so-called “good cholesterol”; the higher the HDL cholesterol level, the lower the risk of coronary heart disease (CHD).


Another word for high blood pressure.

Hypertrophic Cardiomyopathy

Enlarged or thickened walls of the heart ventricles which may block efficient blood flow in and out.


Low Density Lipoprotein (LDL)

A fat-like substance that transports cholesterol from the liver to the tissues of the body. LDL is the so-called “bad” cholesterol; elevated LDL levels are associated with increased risk of coronary heart disease (CHD).


Morbid Obesity

The state of having a body mass index of 40% or higher. (Also see Obesity.)

Myocardial Infarction (MI)

The medical term for heart attack. It refers to changes that occur in the heart muscle (myocardium) due to the sudden deprivation of circulating blood. The main change is necrosis (death) of myocardial tissue.


A disease marked by inflammation and damage of the heart muscle, from causes including viral infections, environmental toxins, autoimmune diseases or reactions to medications.



The state of being well above one’s normal weight. Traditionally defined as being more than 20% above one’s ideal weight (based on a person’s height, age, sex and build), obesity has been more precisely defined by Health Canada as a body mass index (BMI) of 30 or above. [8-Health Canada p2A] Obesity increases the risk of a number of diseases including diabetes, high blood pressure, stroke, heart attack and congestive heart failure.



A small device placed in the chest or abdomen that uses low-energy electrical pulses to achieve normal heart rate and rhythm.


Dead cells, cell debris, fatty acids, cholesterol and calcium that builds up in the walls of blood vessels, restricting the flow of blood.


Cells in your blood that make blood clot. Also called “thrombocytes.”

Platelet Inhibitor

An agent/therapy that prevents or interferes with the formation of blood clots in blood vessels.

Polyunsaturated Fat

A fat containing polyunsaturated fatty acids, molecules derived from animal and vegetable fats, and oils. Unlike saturated fats, polyunsaturated fats are considered beneficial in that they lower cholesterol.


The prostaglandins are a group of physiologically active lipid compounds having diverse hormone-like effects in animals.


Risk Factor

Something that increases a person's chances of developing a disease.



Forces from the outside world impinging on the individual. Stress releases powerful neurochemicals and hormones that prepare the individual for action. This is called the "fight or flight" or stress response.

Stress Test

Any of various tests that assess cardiovascular health and function after application of a stress to the heart, usually exercise but sometimes others such as atrial pacing (regulation of the heartbeat by means of an electrode inserted in the atrium of the heart) or specific drugs. In an exercise cardiac stress test (ECST), the patient exercises on a treadmill according to a standardized protocol, with progressive increases in the speed and elevation of the treadmill (typically changing at three-minute intervals). During the ECST, the patient's electrocardiogram (ECG), heart rate, heart rhythm and blood pressure are continuously monitored. If a coronary arterial blockage results in decreased blood flow to a part of the heart during exercise, certain changes may be observed in the ECG, as well as in the response of the heart rate and blood pressure.


Trans Fat

There are two broad types of trans fats found in food: naturally occurring and artificial trans fats. Naturally occurring trans fats come from animals, while artificial trans fats are created in an industrial process. Trans fats drive up levels of LDL ("bad") cholesterol, which increases the risk of heart attack and stroke.


A type of fat found in your blood. Triglycerides come from foods and are also products of the body.


Very-low-density Lipoprotein (VLDL)

A substance released by the liver that transports fat, mainly triglycerides, to the tissues of the body. VLDL is the so-called “bad” cholesterol; elevated LDL levels are associated with increased risk of coronary heart disease (CHD).