The A-Z of Your Heart

Confused by medical jargon? Here are some of the terms you might hear when you're talking to your doctors or nurses. Our A-Z doesn't replace their advice, but it might help you understand it.

Look at your heart

First, let's look at your heart. Click on the image on the right to watch an animation all about your heart before reading our A-Z.

Ablation
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
When someone has chest pain or disomfort, sometimes it is difficult for the dcotor to tell whether a person may be having unstable angina or a heart attack. 'Acute coronary syndrome' is the term used when this happens. Syndrome means a set of symptoms that happen together and coronary means to do with the arteries.

Alpha-blocker A
Drug used for treating high blood pressure.

Aneurysm
Balloon-like swelling in an artery or wall of the heart.

Angina
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. More information in our booklet Angina

Angiogram
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. More on this in our booklet Tests for Heart Conditions

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. More on this in our booklet Coronary Angioplasty and Coronary Bypass Surgery

Arrhythmia
A disorder of the normal heart rhythm.

Atheroma
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.

Atrial fibrillation
A type of arrhythmia (abnormal heart rhythm) in which the atria (the upper two chambers of the heart) beat very rapidly. Atrial fibrillation can cause quite unpleasant palpitation and sometimes breathlessness.

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. More on this in our booklet Blood Pressure

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 rehabilitation
The process which helps people with heart disease to regain and, if possible, improve their health. A cardiac  rehabilitation programme is a programme for people who have had a heart attack or heart surgery, which covers exercise, relaxation, support and education to encourage long-term lifestyle changes. More in our booklet Cardiac Rehabilitation

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

Cholesterol
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. More on this in our booklet Reducing Your Blood Cholesterol

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.

Coronary artery bypass surgery
An operation to bypass a narrowed section or sections of coronary arteries and improve the blood supply to the heart. More on this in our booklet Coronary Angioplasty and Coronary Bypass Surgery.

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.

Diuretic
Also known as ‘water tablets’. Diuretics increase the output of water and salt in the urine. More in our booklet Medicines for the Heart

ECG
A test to record the rhythm and electrical activity of the heart. ECG stands for ‘electrocardiogram’. More in booklet Tests for Heart Conditions

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

GTN
Stands for ‘glyceryl trinitrate’. A drug used as a spray or tablet under the tongue to relieve, or to help prevent, angina attacks. It can also be given as an infusion (through a vein) in hospital.

HDL
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. More in our booklet Heart Attack.

LDL
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.

MRI
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 mechanical valve. More in booklet Tests for Heart Conditions

Palpitation
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. More in our booklet Palpitation

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

Statin
A drug used to reduce cholesterol levels.

Supraventricular tachycardia
A disturbance of heart rhythm caused by rapid electrical activity in the upper chambers of the heart.

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

Transplant (heart transplant)
An operation to replace the entire heart with one from someone else. More on this in our booklet Heart Transplantation

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.

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. More on this in our booklet Valvular Heart Disease

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

More information

For our full list of terms, please see our booklet Heart Terms Explained

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