If you're diagnosed with heart disease or have had a heart attack, your doctor may use many unfamiliar terms. Learn the ABCs of cardiovascular disease with this handy guide.



A procedure used to correct certain types of heart-rhythm disorders. The doctor finds out where the abnormal heart rhythm causing the palpitation is coming from, and uses radio frequency energy to destroy the abnormal electrical pathways.

Acute coronary syndrome

A pattern of symptoms of chest pain including both unstable angina and heart attack.

Aerobic exercise

Repetitive, rhythmic exercise involving the large muscle groups. Examples include brisk walking, cycling and swimming.


The doctor who gives an anaesthetic to make you sleep during an operation.


A balloon-like swelling in an artery or in the wall of the heart.


Heaviness or tightness in the centre of the chest, which may spread to the arms, neck, jaw, back or stomach. Or it may affect just the neck, jaw, arms or stomach. Angina is caused when the arteries to the heart become so narrow due to atheroma or spasm that not enough oxygen-rich blood can reach the heart muscle when the body is making high demands on it – such as during exercise. The pain can also happen when a person is resting.


An X-ray picture of the blood vessels which shows whether the arteries are narrowed and, if so, how narrow they have become. An angiogram can be used to examine the coronary arteries (a coronary angiogram)  or other arteries in your body.


A test to show whether your arteries are narrowed and how narrow they have become. See also angiogram above.

Angioplasty with stenting

A treatment to widen a narrowed artery. A catheter (a fine, flexible, hollow tube) with a small inflatable balloon at its tip is passed into an artery in either your groin or your arm. It goes as far as the point in the coronary artery where a blockage has been detected. The balloon is inflated and it flattens the blockage. The balloon is then deflated and a stent made of stainless-steel mesh is left in place in the artery to strengthen the artery wall.


A device which is sometimes used to close the puncture site in the groin after angioplasty. The device will dissolve once the puncture site has healed.


Vitamins and other substances found mainly in vegetables and fruit.


The large artery (blood vessel) leading out of the left side of your heart and supplying the whole body with blood. 

Aortic aneurysm

A balloon-like swelling of part of the wall of the aorta.

Aortic root

The base of the aorta immediately after it leaves the left ventricle of the heart. The aortic root is where the coronary arteries start from.

Aortic valve

The valve which regulates the flow of blood from the left ventricle into the aorta.


A disorder of the normal heart rhythm.


A blood vessel carrying blood from your heart to the rest of your body.


An anti-platelet drug used to help prevent blood clots forming.


Fatty material that can build up within the walls of the arteries. When atheroma affects the coronary arteries, it can cause angina, heart attack or sudden death. When it affects the arteries to the brain, it may cause a stroke. When it affects the leg arteries, it causes peripheral arterial disease. Atheroma can build up for many years before it causes problems.


The build-up of fatty material within the walls of the arteries.

Atrial fibrillation

The two upper chambers of your heart.They act as collecting chambers to fill the ventricles (the two lower chambers of the heart).

Atrio-ventricular node

The part of the heart through which the electrical impulses pass from the atria to the ventricles,to stimulate a heartbeat.


One of the two upper chambers of your heart.

AV node

See atrio-ventricular node above.

  Back to Top


Balloon treatment

A procedure to stretch a narrowed valve or artery.

Beating heart surgery

Surgery that is carried out on the beating heart. This can be done through a wound along the chest bone or using minimally invasive surgery. A heart-lung machine is not needed for this type of surgery.


A procedure in which a small specimen of tissue is taken for examination.

Blood lipids

Fatty material found in the blood.

Blood pressure

The pressure of blood in the arteries. The heart is a pump that beats by contracting and then relaxing. The pressure of the blood flowing through your arteries varies at different times in the heartbeat cycle. The highest pressure (called systolic pressure) is when the beat or contraction of the heart forces your blood around the circulation. The lowest pressure (diastolic pressure) is between heartbeats.


BMI stands for ‘body mass index’. This is a formula to work out whether a person is a healthy weight.


A slow heart rate – usually less than 60 beats a minute.

Bypass surgery or CABG

CABG stands for‘coronary artery bypass graft’.

  Back to Top



The smallest of the blood vessels. They join the small arteries to the small veins..


To do with the heart.

Cardiac arrest

When the heart stops. This usually happens suddenly, either as a result of a heart attack or if someone has a severe injury and loses a large amount of blood.

Cardiac catheterisation

When a long, flexible, hollow, plastic tube called a ‘catheter’ is passed into a vein or artery either in the groin or the arm and is gently guided through the blood vessels. This technique is used to take angiograms, or to carry out an angioplasty.

Cardiac enzyme tests

Blood tests to measure the level of certain enzymes in the blood. When the heart muscle is damaged after a heart attack, certain enzymes are released into the blood. The amount of enzymes released depends on how severe the damage is.


A doctor specialising in heart disease.


A disease of the heart muscle causing the heart to get bigger.

Cardiopulmonary resuscitation

Actions to restore breathing or circulation, or both.


To do with the heart and blood vessels.


A procedure to restore a regular heart rhythm. For more on this, see our booklet Palpitation.


A fine, hollow, plastic tube.

Chest drain

A tube which allows blood or fluid which builds up in the chest to be removed safely.


A fatty material mainly made in the body by the liver. Too much cholesterol in the blood can increase the risk of atheroma (fatty material) building up in the coronary arteries, leading to coronary heart disease.

Congenital heart disease

Heart conditions in which there are abnormalities of the structure of the heart or major blood vessels. These abnormalities are present at birth and some may be hereditary.

Contrast medium

A substance that is injected into a vein so that the blood vessels can be seen more easily during tests such as an X-ray or CT scan. 

Coronary arteries

The arteries that branch off the aortic root and which supply blood to the heart muscle. 

Coronary artery bypass surgery or coronary bypass surgery

An operation to bypass a narrowed section or sections of coronary arteries and improve the blood supply to the heart.

Coronary heart disease

When the walls of the coronary arteries (the arteries that supply blood to the heart muscle) become narrowed by a gradual build-up of fatty material called atheroma. When atheroma affects the coronary arteries, it can cause angina, heart attack or sudden death.

Coronary thrombosis

When a blood clot forms in a coronary artery. This may lead to a heart attack.

CT scan

A type of X-ray used for looking at organs in the body.

  Back to Top



A procedure  to restore a regular heart rhythm. A controlled electric shock is delivered through the chest wall to the heart, using a defibrillator (see below).


A device which delivers a controlled electric shock through the chest
wall to the heart, in order to restore a normal heart rhythm.


A disease caused when the body does not produce enough insulin, or when the cells of the body can no longer use the insulin. Type 1 diabetes is present from birth. Type 2 diabetes develops later.

Diastolic blood pressure

When measuring blood pressure, the diastolic blood pressure is the lowest pressure, which happens in between heartbeats while the heart is resting.


A health professional who can advise on healthy eating and special diets.

Discharge (from a wound)

Leaking or oozing.

Discharge rate (of a pacemaker)

The rate at which electrical impulses are generated by a pacemaker.

Drug-eluting stent

A stent is a short tube of expandable  mesh,  like a scaffold, which is inserted at the part of the artery which is to be widened by coronary angioplasty. A drug-eluting stent isa stent which has been coated with medication to help prevent the artery closing off again.

Dual chamber pacemaker

A pacemaker with two electrical leads. One is attached to the right atrium and one to the right ventricle.

  Back to Top



A test to record the rhythm and electrical activity of the heart. ECG stands for ‘electrocardiogram’.

24-hour ECG

Continuous recording of an ECG (see above) over 24 hours to look at the heart rhythm. The recorder produces an ECG which can be analysed later.


An ultrasound picture of the heart which shows the structure of your heart and how it is working.


The procedure of taking an echocardiogram.

Ectopic beat

An extra heartbeat.

Electro- physiological testing

A technique for detecting and analysing abnormal heart rhythms.


A clot of blood which starts in one part of the body, breaks off into the circulation and ends up lodged somewhere else.


A condition causing permanent destruction of part of the lungs.


An infection of the inner lining of the heart, usually affecting the valves.


Proteins that help stimulate chemical reactions in your body.

Epicardial implantation (of a pacemaker)

When the electrode lead of a pacemaker device is attached directly onto the outer surface of the heart (the epicardium).


The outer surface of your heart.

Exercise ECG or exercise electro- cardiogram

When the rhythm and electrical activity of your heart are recorded while you are pedalling an exercise bicycle or walking on a treadmill.

  Back to Top


Familial hyper- cholesterolaemia

An inherited condition in which the blood cholesterol level is very high.


A protein formed by clotting factors in the blood. It acts as part of the clotting process.

  Back to Top



To do with the stomach or intestine..


Relating to genes or heredity –  the characteristics that parents pass on to their children through their genes.


General practitioner, or family doctor.

  Back to Top



Stands for ‘high-density lipoprotein’. This is the ‘protective’ cholesterol. High-density lipoproteins return excess cholesterol to the liver.

Heart attack

When one of the coronary arteries becomes blocked by a blood clot and part of the heart muscle is starved of oxygen,  causing damage to the heart.

Heart block

When the electrical impulses of the heart are slowed down or delayed by an interruption in the heart’s normal electrical activity.

Heart failure

When the pumping action of the heart is inadequate.

Heart-lung machine

Blood is diverted through this machine during heart surgery, to keep the brain and other organs working while the heart is being operated on.

Heart rate

The number of heartbeats each minute.

Heart sounds

The normal sounds of the heart, heard through a stethoscope. The sounds are made by the heart valves opening and closing.


Passed on from one generation to another.

High blood pressure

High blood pressure happens if the smaller blood vessels in the body become narrow and cause the pressure to build up. High blood pressure is also known as hypertension.


A graft of tissue – for example, a heart valve – taken from one body and put into another of the same species.


Hormone replacement therapy.

Hyper- cholesterolaemia or hyperlipidaemia

When there is too much cholesterol in the blood.

  Back to Top



Stands for ‘implantable cardioverter defibrillator’. A device which is implanted within the chest wall. It monitors the heart rhythm, senses if there is a severe disturbance in heart rhythm and
if necessary delivers an electrical impulse or an electrical shock, to stop the abnormal rhythm.


Intensive care unit.

Immune system

The cells and proteins in the blood and tissues that help protect your body against attack from bacteria and viruses.

Implantable loop recorder

A recording device used for finding out about the cause of infrequent symptoms such as dizzy spells or blackouts. It is implanted just under the skin on the chest. It continuously monitors the heartbeat for up to 14 months, and can record any abnormal events that it is programmed to detect.


A surgical cut.

Intermittent claudication

A cramp-like pain mostly in the calf and leg muscles, brought on by walking and relieved by rest.


Into a muscle..

Intravascular ultrasound

A technique for taking ultrasound pictures of the wall of an artery from inside the artery itself.


Into a vein.

Introducer sheath

The device through which a catheter is inserted into an artery.


When not enough blood is being supplied to the tissues or muscle. Cardiac ischaemia causes the pain known as angina.

Ischaemic heart disease

When not enough blood is flowing through the coronary arteries to the heart.

Isometric exercise

Exercises in which muscle tension is produced without moving a joint. Examples include pushing against a wall or stationary object with straight arms, or holding dumb-bells still at shoulder height.

  Back to Top



Stands for ‘low-density lipoprotein’. This is the more ‘harmful’ cholesterol. Low-density lipoproteins (LDL) carry cholesterol from your liver to the cells of your body.

Left heart failure

Heart failure caused by an inefficient pumping action of the left side of the heart.

Left ventricular hypertrophy

When the heart muscle of the left ventricle becomes thickened.

Lipid-lowering drug

Fatty material in the blood,  including HDL cholesterol, LDL cholesterol and triglycerides.


Combinations of cholesterol and proteins made in the body. The two common types are LDL and HDL.

Low blood pressure

When the blood pressure is below about 90/60.

  Back to Top


Mechanical valve

An artificial, manufactured valve.


Stands for ‘minimally invasive direct access coronary artery bypass’ surgery. This is surgery on the coronary arteries carried out while the heart is beating (instead of using a heart-lung machine).

Minimally invasive surgery

Surgery which is carried out using a smaller wound than usual.

Mitral valve

The valve which regulates the flow of blood from your left atrium to your left ventricle.

Mitral valve prolapse

When a mitral valve bulges backwards into the left upper chamber (atrium) of the heart.

Mitral valve stenosis

Obstruction of the mitral valve caused by narrowing or thickening of the valve.

Mitral valvuloplasty

A procedure to stretch a narrowed mitral valve.


Millimetres of mercury. Unit used for measuring blood pressure.


Millimols per litre. Unit used for measuring the level of various substances in the blood, such as cholesterol or potassium.

24-hour monitoring (of blood pressure)

When blood pressure measurements are recorded at pre-set intervals over a 24-hour period.

Mono- unsaturated fat

A type of fat found in foods such as olive oil, rapeseed oil and avocado, and in some margarines and spreads.


Stands for ‘magnetic resonance angiogram’. A type of angiogram which provides pictures of the arteries, using a magnetic field and radio impulses.


Stands for ‘magnetic resonance imaging’. A technique which produces detailed pictures of internal organs of the body. You cannot have this test if you have a pacemaker, an implantable cardiac defibrillator, a cardiac stent or a mechanicalvalve.


An unusual sound from the heart, heard while listening with a stethoscope. It is different from the normal sound of the heart.

Myocardial infarction

A heart attack.

Myocardial perfusion scan

A test to assess the level of function of the heart muscle. It also assesses the blood flow to the heart


The heart muscle.

  Back to Top


Negative ECG

A negative exercise ECG (electrocardiogram) is when there are no unusual or obvious changes on the ECG while you are exercising.


A chemical found in tobacco smoke.

Nicotine- replacement products

Aids to help you stop smoking, which contain nicotine. They include patches, gum, nasal spray and inhalator.

non-Nicotine replacement

Aids to help you stop smoking, which do not contain nicotine.


Stands for ‘nicotine-replacement therapy’.

  Back to Top



Being very overweight, or carrying too much body fat.


Swelling caused by fluid.


A type of fatty acid found in fish oils. It is found in oily fish such as herring, mackerel, pilchards, sardines, salmon, trout and fresh tuna.


Thinning of the bones.

  Back to Top



A device which is implanted in the chest, to stimulate contractions of the heart.

Pacemaker registration card

A card which has details of the make and model of your pacemaker.


When you become aware of your heartbeat, for example when it feels as if it is beating abnormally fast or slowly, or irregularly or heavily.


Intermittent. Stops for a while and then starts again.

Passive smoking

When someone inhales another person’s smoke.

Peripheral arterial disease

Disease of the arteries that supply the blood to the limbs.


A specialist who teaches breathing and coughing techniques, and encourages people to get moving again safely, for example after an operation.


Small blood cells which are essential for clotting.


When the air leaks from the lungs into the chest cavity.

Polyunsaturated fat

A type of fat found in foods which come from plants and fish – such as cornflower oil, sunflower oil, fish oil, and some margarines and spreads.


After an operation.

Pre-admission clinic

A clinic  where you can meet the hospital staff, and where all the medical tests and investigations that need to be done before an operation are carried out.

Pre-eclamptic toxaemia

A condition of pregnancy that includes high blood pressure.


Before an operation.


Outlook. Forecast of the course of a disease.




A balloon-like swelling in the wall of an artery or wall of the heart.


Stands for ‘percutaneous transluminal coronary angioplasty’. This is another name for coronary angioplasty.


To do with the lungs.

Pulmonary artery

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

Pulmonary valve

The valve which regulates the flow of blood from your right ventricle to your pulmonary artery.

Pulse generator

The part of a pacemaker that contains the electrical circuitry and the battery.

Purkinje system

The fibres in the heart which act like ‘wires’ to send electrical impulses through the lower chambers or ventricles of the heart.

  Back to Top


Radionuclide test

A test which provides information about the blood flow to the heart and heart muscle.


When a valve does not close properly, allowing blood to leak backwards.


Actions to restore the breathing or circulation, or both.


Any procedure that restores blood flow to a part of the body.

Right heart failure

Inefficient pumping action of the right side of the heart.

Risk factor for coronary heart disease

Something that can increase the risk of getting coronary heart disease.

  Back to Top


Saturated fat

A type of fat found mainly in food from animal sources – particularly dairy and meat products.

Sick sinus syndrome

A condition affecting the heart’s natural pacemaker. It changes the normal rhythm of the heart..

Single chamber pacemaker

A pacemaker with one electrical lead, either to the right ventricle or right atrium of the heart.

Sino-atrial node

See sinus node below.

Sinus bradycardia

A regular but slow heart rhythm – usually less than 60 beats a minute.

Sinus node

Also known as the heart’s natural pacemaker. This is a group of cells in the right atrium of the heart which produces the electrical impulses that control the heart’s pumping action.

Sinus tachycardia

A regular but fast heart rhythm – usually more than 100 beats a minute.


A chemical element found in salt. It can contribute to high blood pressure.


An action in the wall of a blood vessel that causes it to narrow and reduce the blood supply to the muscle it is supplying. If the spasm happens in the coronary arteries, it can lead to pain such as angina.

Sphygmo- manometer

An instrument used to measure blood pressure.

Stable angina

Angina that comes on with a particular amount of exercise and is well controlled with drugs..


An abnormal narrowing of a blood vessel or valve, causing obstruction to the normal blood flow.


A short tube of expandable mesh which is inserted at the part of the artery which is to be widened by coronary angioplasty. The stent helps to support the artery wall.

Stress echo- cardiography

When an echocardiogram  is done after the heart has been put under stress – either with exercise or with a drug.


Damage to the brain caused by a lack of blood supply to the brain. The blood supply to the brain can be interrupted either by atheroma, or by a blood clot or a blood vessel bursting.


Under the tongue.

Supraventricular tachycardia

Supraventricular tachycardia


A surgical stitch.

Systolic blood pressure

When measuring blood pressure, systolic blood pressure is the highest pressure, which occurs when the beat or contraction of your heart forces the blood around the circulation.

  Back to Top



A fast heart rate – usually greater than 100 beats a minute.


A type of radioactive substance used in radionuclide tests to study the size and pumping activity of the heart chambers.


A type of radioactive substance used in radionuclide tests to study the blood flow to the heart muscle.


When a blood clot forms in the blood vessels or heart.


A blood clot.

Tissue valve

Valve from an animal or human. Sometimes used to replace a diseased or damaged heart valve.

Trans- oesophageal

Through the oesophagus (gullet).

Trans- oesophageal echo- cardiography

A procedure which involves taking detailed pictures of the heart from the gullet (oesophagus) which lies behind the heart.

Transplant (heart transplant)

An operation to replace the entire heart with one from someone else.


Through a vein.

Tricuspid valve

The valve which regulates the flow of blood from the right atrium to the right ventricle.


A fatty material found in the blood..

Troponin test

A blood test to measure the level of a protein called troponin which is released into the bloodstream after a heart attack.

  Back to Top


Unsaturated fat

A type of fat found mainly in foods from plant and fish sources. Unsaturated fats include polyunsaturated.

Unstable angina

Angina which has just developed for the first time, or which was previously stable but has recently got worse or changed in pattern. For example, it can come on even when the person is resting.

  Back to Top



A device to make sure that fluid flows in one direction only.

Valve incompetence

When a valve does not close properly, allowing blood to leak backwards.

Valve stenosis

Narrowing of the valve.

Valvular heart disease

When one or more of the four valves in the heart are diseased
  or damaged, affecting the flow of blood in the heart.

Varicose veins

Veins that have become stretched and dilated (widened).


To do with the blood vessels.


A vessel carrying blood back from various parts of the body to the heart.


An artificial breathing machine.


The two main pumping chambers of the heart.

Ventricular fibrillation

A life-threatening disturbance in the heart rhythm which causes the heart to quiver or ‘fibrillate’ in a disordered way.

Ventricular tachycardia

A condition where there is a fast heart rate in the ventricles (the two larger chambers of the heart).

  Back to Top


Waist circumference

The measurement around your waist. This measurement can be used to assess your risk of developing heart disease.

Waist-hip ratio

A calculation, based on your waist and hip measurements, used to find out if you are a healthy weight.


A type of anticoagulant drug, used to reduce the risk of blood clots forming

  Back to Top



A graft using animal tissue.

  Back to Top