Glossary of terms

Glossary of terms

The following is an alphabetical listing of terms associated with cardiology conditions. Click on any letter to jump to the definitions. If you can’t find the answer to your question here, try these:

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Ablation (Catheter Ablation)
A treatment for an abnormal electrical pathway that causes an abnormal heart rhythm.

Angina pectoris
When the heart muscle does not get enough oxygen rich blood to meet the demand, the heart muscle experiences a hunger for more oxygen, and the patient experiences angina. Symptoms of angina include chest pressure, tightness, heaviness and discomfort in the arm, jaw, back, or neck.

A procedure to widen the interior of a blood vessel with inflation of a balloon on the end of a catheter.


A balloon-like sac in the wall of an artery, vein, or heart caused by a weakening of the wall by injury, disease, or abnormality present at birth.

Antiarrhythmic drugs

Medicines used to treat heart rate or rhythm disorders.

A drug that delays clotting.

A medicine prescribed to reduce blood pressure.

The main artery that receives blood from the left ventricle of the heart and flows to the body.

Aortic valve

The heart valve between the aorta and the left ventricle.

An abnormal rhythm of the heart.


An x-ray using opaque dye to study arteries (usually coronary arteries).

One of the series of vessels that carries blood from the heart.

Atria (atrium – singular)

The two upper holding chambers of the heart.

Atrioventricular node (AV node)
Conducting tissue at the bottom of the right atrium in which electrical impulses must pass to reach the ventricles.

Automatic Implantable Cardioverter Defibrillator (AICD)

A surgically implanted device that checks the hearts electrical signals and delivers electrical therapy when it senses a dangerous heart rhythm.

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Balloon catheter
Used to dilate a narrowed artery.

Blood pressure
The pressure exerted by the heart in pumping blood.

An unusually slow heart rate.


A procedure using radiation treatment to prevent reblockage following angioplasty or stent placement in a coronary artery.

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Relating to the heart.

Cardiac arrest
The blood ceases to circulate and the heart stops beating.

Cardiac Catheterization
Putting a catheter into an artery or vein to examine the heart using x-ray images with dye injection.

Cardiac Doppler
A test using sound waves to produce images of the heart as it is beating.

A doctor specializing in the diagnosis and treatment of heart disorders.

Cardiopulmonary Resuscitation (CPR)
Used when the heart stops beating, a method of mouth-to-mouth breathing and external cardiac compression to keep oxygenated blood circulating.

A fine, flexible tube that is inserted into an artery or vein.

The process of inserting a catheter into a vein or artery and guiding it through the heart chambers and surrounding vessels for purposes of examination or treatment.

Collateral Circulation
A network of small arteries in the heart that are normally closed. When a coronary artery is blocked, they may open to carry blood to the heart muscle.

Existing at birth.

Congestive Heart Failure
The inability for the heart to pump the blood out of the heart. The build up of fluid on lungs and tissue can be sudden or gradual.

Coronary Artery Bypass Graft Surgery
An operation to improve circulation to a coronary artery by surgically bypassing blocked or narrowed sites.

Caused by insufficient oxygen. Causes a blueness to the skin, lips, and nail beds.

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A machine to treat abnormal heart rhythms.

Diastolic blood pressure
The bottom of the two blood pressure numbers.Measures the heart at rest.

A drug that removes excess fluid from the body by increasing urination.

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A procedure in which pulses of sound are transmitted into the body and the echoes from the heart are recorded and charted. The Doppler color flow gives a picture to show the direction of blood flow.

Swelling due to excessive fluid in the body.

Electrocardiogram (ECG)
A printout of the electrical impulses produced by the heart.

Electrophysiology Study (EP)
A study to diagnose or locate heart rhythm problems.

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A heart rhythm that occurs when the heart muscle fibers contract individually.

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Transplanted tissue from one area of the body to another (As in use of a saphenous vein graft from the leg to bypass a coronary artery blockage during coronary artery bypass surgery).

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Heart block
The electrical impulses causing the heart to beat are slowed or blocked along the pathway between the upper and lower chambers of the heart.

Heart-lung machine (cardiopulmonary bypass)
An machine that oxygenates and pumps the blood during open-heart surgery.

A medicine used to slow the clotting of the blood.

Holter monitoring
A portable diagnostic tool used to record heart rhythm and rate.

Blood pressure above the normal range.

When cells increase in sized and cause enlarged tissues and organs.

Low blood pressure.

Low oxygen content in the body.

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Ischemic heart disease
Ailments caused by a decreased blood supply due to narrowing of the coronary arteries.

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Mitral Valve
The valve between the left ventricle and left atrium having two flaps or cusps that prevent backflow.

The noise between normal heart sounds caused by blood flow.

The muscle of the heart wall that contracts to push out blood.

A nuclear perfusion study of blood flow to the heart muscle.

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A medicine that dilates arteries causing decrease in workload on the heart.

NOGA (Cardiac Navigation System)
Three-dimensional mapping of electromechanical function of the heart to assess blood flow.

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Open-heart surgery
An operation inside the heart while the patient is on a heart lung machine.

A method of measuring the oxygen content of blood.

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A surgically implanted electrical device used to cause heart contractions and control heartbeats.

Irregular heartbeats felt as a skip or momentary cessation of the heart.

Inflammation of the sac around the heart.

A sac surrounding the heart and the vessels close to the heart.

Platelet Inhibitor
A medicine that reduces clotting by inhibiting platelets in the blood.

Pulmonary artery
The artery that carries blood to the lungs from the heart.

Pulmonary Hypertension
High blood pressure in the blood vessels of the lungs.

Pulmonary valve
The valve between the pulmonary artery and the right ventricle having three cusps that open and close with the heartbeat.

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Sino-atrial node (S-A node)
The heart’s natural pacemaker, located in the upper part of the heart, normally regulates your heart rate.

The wall dividing the heart chambers.

An obstruction or narrowing of an opening (as in coronary artery stenosis) or valve.

A metallic scaffold placed over a delivery balloon catheter that is positioned in the narrowed site of an artery.

Systolic blood pressure
The pressure measured when the ventricle contracts. The highest of the pressures measured.

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Very quick heart rate.

Treadmill stress test
A walk on a treadmill during which time the electrical impulses in the heart are recorded on an ECG machine.

A medicine administered to breakdown clots.

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One of the lower pumping chambers of the heart.

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Wolff-Parkinson-White Syndrome
A condition caused by an abnormality in the electrical system of the heart which normally tells the heart muscle when to contract.

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An Xray of the chest will often be performed as part of an initial assessment or a follow up appointment. This will show the size and shape of the heart and also helps to demonstrate effects of heart problems on the lungs (e.g. congestion of the lungs). Enlargement of the heart and abnormalities of its shape may give valuable information about many heart defects and their severity.

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Y wave
The wave in the atrial and venous pulse curves reflecting rapid filling of the ventricles just after the atrioventricular valves open.

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A protein found in fibroblasts, smooth muscle and pigmented retinal epithelium.