Look up a medical word

Ablation is a medical term for removal of an area of tissue from the body. There are different types of ablation that may be used for people with cardiomyopathy.

• Catheter ablation (AV node ablation and radio frequency ablation) is used to treat some forms of arrhythmias (abnormal heart rhythms). Here, a catheter (thin tube) is tunnelled through a vein or artery in the groin into the heart, and radio waves are used to treat the area of heart muscle that is causing the arrhythmia and therefore stop the transmission of electrical signals that affect the heart rhythm. 
• Septal alcohol ablation is a form of treatment for hypertrophic cardiomyopathy where the area of thickened heart muscle causes an obstruction to the blood flow out of the ventricle (sometimes referred to as left ventricular outflow tract obstruction (LVOTO)). Here, alcohol is used to treat and reduce the area of thickened muscle that is causing the obstruction, so that it no longer affects the blood flow out of the heart. This is an alternative to surgical myectomy.

A type of medication used to treat cardiomyopathy. ACE stands for angiotensin-converting enzyme inhibitor. This medication reduces the workload of the heart in two ways: it relaxes the smooth muscles around the blood vessels, and it reduces the volume of the blood by reducing the amount of fluid in the body. Together, this makes it easier for blood to be pumped out of the heart and reduces the amount of oxygen the heart needs. ACE inhibitors are one type of a drug that is vital in treating conditions that cause heart failure such as dilated cardiomyopathy (dcm). They are also used to reduce and control high blood pressure (hypertension).

This is a group of rare ‘infiltrative’* conditions caused by a build-up of an abnormal protein (called amyloid) in the body. Amyloid is an abnormal protein because, unlike normal proteins, it cannot be easily broken down in the body, and can collect in the body’s tissues and organs. Where this build-up stops the tissues and organs working properly it can cause the condition amyloidosis.

There are many different types of amyloidosis, and where amyloid builds up in the heart muscle it can affect how well the heart functions, and cause arrhythmias, heart failure, dilated cardiomyopathy or restrictive cardiomyopathy.

Although there is no cure for amyloidosis, the symptoms can usually be treated and the production of amyloid reduced.

*Infiltrative refers to the build-up of substances in the cells and tissues.

A rare, recessive, genetic ‘storage’* condition, caused by a mutation in a gene called ‘GLA’, carried on an X chromosome. This results in a build-up of a fat-like substance called glycosphingolipids in organs and tissues of the body (including the skin, eyes, brain and nervous system, kidneys and heart) which affects their ability to function properly.

Depending on where in the body the build-up is, there are a number of different symptoms. These can include pain in the hands and feet, tinnitus, skin rash, and kidney and bowel problems.

When there is a build-up in the heart, it can cause cardiomyopathy as the heart muscle becomes thickened and stiffened. This can cause symptoms such as palpitations, chest pain, difficulty breathing and syncope, and can cause heart failure.

*Storage condition refers to how substances are stored in the body.

The medical term for a type of chest pain caused by reduced oxygen levels getting to the heart. This can happen when the blood supply to the heart is reduced or restricted due to the coronary arteries becoming narrower. People with cardiomyopathy can sometimes experience an angina type chest pain, although it is not always clear why this is.

A medical test that is used to see the structure of blood vessels. It involves using a catheter (long flexible tube inserted into a blood vessel in the groin) to inject a coloured dye into the vessel and having an x-ray to image that area to look for blockages. Where the test is used for blood vessels in the heart it is often referred to as coronary angiography.

A type of medication used to treat high blood pressure and heart failure in cardiomyopathy.

ARBs work by dilating (enlarging) blood vessels to and from the heart which helps to reduce blood pressure. They do this by blocking a chemical called angiotensin II, which normally causes the muscles around blood vessels to contract, which in turn makes the blood vessel narrower and raises blood pressure. Instead, ARBs block angiotensin II and reduce its effect on causing the muscles to contract, which helps blood vessels to dilate and reduce blood pressure. This makes it easier for the heart to pump blood and reduces the symptoms of heart failure.

ARBs have a similar effect as ACE inhibitors, although they work in a different way and may have fewer side effects. For example, some people experience a persistent cough with ACE inhibitors and so are prescribed ARBs instead.

Alongside diuretics, beta blockers and ACE inhibitors, ARBs are one of the standard drugs recommended for the treatment of heart failure conditions by the National Institute for Health and Care Excellence (NICE)  in their guidelines (revised 2015). 

An example of an ARB is valsartan.

A type of medication which controls the rhythm of the heart. People with cardiomyopathy may develop arrhythmias – abnormal heart rhythms – due to irregularities in the electrical activity of their heart. These drugs are used to correct the abnormality of the heart rhythm.  An example of this type of medication is Amiodarone.

A type of medication which helps to prevent blood clots from forming. It is given to people who are at high risk of blood clots forming, such as people with atrial fibrillation, as the uneven flow of blood through the heart could cause a clot to form which could cause a stroke if it enters the brain. An example of this type of medication is warfarin.

The main artery that leaves the left side of the heart, and transports blood to the rest of the body.

The bottom 'point' of the heart, which is part of the left ventricle as the heart lies in the chest the apex points down and towards the left.

A form of hypertrophic cardiomyopathy (HCM) where the thickened area of muscle affects the apex of the heart. It does not usually cause an obstruction to the blood flow leaving the left ventricle.

A general term for abnormal heart rhythms. Examples of arrhythmias include atrial fibrillation, ventricular tachycardia and heart block. Arrhythmias can reduce how effective the heart is and some can be life-threatening and so usually need to be treated with medication or a medical device.

Another name for Arrhythmogenic right ventricular cardiomyopathy (ARVC), as this condition sometimes affects the left side of the heart.

A type of cardiomyopathy where there is a problem in the structures than bind together the heart muscle cells. When the heart is placed under stress, for example high level exercise, these structures can break down. The affected heart muscle cells will die and be replaced by scar tissue and fat. This makes the heart walls thinner and weaker, and less able to pump blood than normal. Although this usually affects the right ventricle, it can affect the left ventricle as well, and so is also known as arrhythmogenic right ventricular cardiomyopathy (ARVC). We have more information on the cardiomyopathy information section of our website. 

A type of blood vessel, which transports blood away from the heart and around the body.

A form of hypertrophic cardiomyopathy where the thickened area of heart muscle is in the septum of the heart. The thickened area of the septum may cause an obstruction in the flow of blood leaving the left ventricle.

A form of hypertrophic cardiomyopathy where the thickened area of heart muscle is in the septum, and obstructs the flow of blood out of the left ventricle of the heart (referred to as left ventricle outflow tract obstruction or LVOTO). This type of hypertrophic cardiomyopathy is sometimes referred to as HOCM.

The most common form of hypertrophic cardiomyopathy (HCM), where the thickened area of heart muscle is in the septum, but does not obstruct the blood out of the left ventricle of the heart.

The two chambers at the top of the heart which receive blood from the vena cava (the right atrium) and the pulmonary vein (the left atrium). Blood from the atria then flows into the ventricles.

A common type of arrhythmia or abnormal heart rhythm. AF is caused by disruption of the electrical messages that normally cause the heart muscle to contract, which means that it can’t contract properly. Instead, the atria beat very quickly and are uncoordinated. This can make the flow of blood around the atrium ‘turbulent’, and the heart less efficient at pumping out blood. AF can be paroxysmal (happening for a short time) or persistent (happening all the time).

Although in itself it is not life-threatening, it can cause palpitations, and can increase the risk of blood clots forming, which can increase the risk of a stroke. AF is often treated with anticoagulants to reduce the chance of blood clots forming. In some cases electrical cardioversion is used to shock the heart back into a normal rhythm.

A common type of arrhythmia (abnormal heart rhythm) which can develop into atrial fibrillation. In atrial flutter the atrium beats faster than normal which causes it to be out of sync with the beating of the ventricle below. This happens due to a problem with the normal electrical signalling of the heart, which usually causes the chambers of the heart to beat in a synchronous rhythm. Unlike atrial fibrillation (where the heart beats fast and irregularly), in atrial flutter the atrium beats too fast but it still regular.

This pattern can be clearly seen on an ECG.

This is a portable machine that can be used to detect lethal abnormal heart rhythms or a lack of heart beat, and can give an electric shock (defibrillation) to get the heart back into a normal rhythm.

They are becoming more common, and can be found in community settings such as shopping centres and towns. The machine gives instructions about how to use it correctly, and is an important addition to CPR in assisting people in cardiac arrest.

These relates to how genetic conditions are inherited. ‘Autosomal’ means that the gene occurs on one of the autosomes. ‘Dominant’ means that if an individual inherits the gene, they will inherit the condition.

A non-sex chromosome. Humans have 46 chromosomes, arranged into 23 pairs. 1 pair determines the sex of the person (called sex chromosomes). The 22 other pairs do not determine sex, and so are called non-sex chromosomes or autosomes.

An area of specialised muscle cells which lies between the two atria of the heart. The AV node transmits the electrical signal which causes the ventricles of the heart to contract to pump blood out of the heart.

A form of treatment where the electrical messages from the atrium are blocked at the AV node, so that they are not transmitted to the ventricles. This is sometimes used to treat atrial fibrillation. Following this procedure a pacemaker is needed to make the ventricles contract and for the heart to work normally.

A type of medication used to reduce the rate and force of the heart’s contraction, by preventing the stimulation of adrenalin (which would normally make the heart beat faster). Beta blockers are an important group of drugs used to treat heart failure conditions such as dilated cardiomyopathy.

They may also be used for people experiencing symptoms such as chest pain, breathlessness and palpitations, to reduce the risk of heart attack. An example of a beta blocker is bisoprolol.

Another name for the mitral valve.

An electrical medical device used in cardiac resynchronisation therapy (CRT), this is a specific type of pacemaker that helps both sides of the heart to beat together. This is helpful for people who have a delay between the contraction of the right and left sides of the heart (commonly left bundle branch block or LBBB), which can happen due to heart failure.

The biventricular pacemaker (sometimes referred to as CRT-P – (where the ‘P’ refers to the pacemaker function) is a battery-powered device which is implanted under the skin, and connected by leads to the heart. It usually has three leads, which are connected to the right atrium (top chamber of the heart), right ventricle and left ventricle (lower, pumping chambers of the heart). The pacemaker takes over the electrical stimulation of the heart, sending electrical signals to both sides of the heart to cause both ventricles to beat together (in synchrony).

This aims to improve how effectively the heart pumps, increase the output of blood and reduce any symptoms. The devices often include an ICD function and are known as a CRT-D (where ‘D’ stands for defibrillator).

It is called ‘biventricular’ as it stimulates both ventricles to contract – or pump – together.

A measure of heart function. This is measured in millimetres of mercury (mmHg) and is given as two numbers (such as120/80mmHg). The top number is the pressure of blood when the heart beats (and pumps blood out of the heart). The bottom number is the pressure of blood when the heart is resting between beats.

Blood pressure of 140/90mmHg or over is usually considered to be high blood pressure or hypertension, and can increase the risk of heart attack or heart failure. It is usually treated with life-style changes, or with medication such as ACE inhibitors, beta-blockers, calcium channel blockers or diuretics.

Blood pressure of 90/60mmHg or under is usually considered to be low blood pressure or hypotension. Although it may not cause any symptoms, it can reduce the amount of blood getting to your brain and other organs which can cause dizziness or loss of consciousness.

An abnormally slow heart rate, usually below 60 beats per minutes in an adult. Although this may be a usual heart rate for some people and doesn’t cause any problems, it may be caused by a problem with the electrical signalling in the heart and can cause dizziness, light-headedness, loss of consciousness or cardiac arrest.

Shortness of breath or the feeling of struggling to breathe. This can be a symptom of heart failure, and is a common symptom of cardiomyopathy. Although it is common during exercise or exertion, when someone feels breathless while resting, this can be due to a build-up of fluid on the lungs. The medical term for this is dyspnoea.

A rare condition, referred to as a channelopathy’*, that affects the sodium ions channels in the cells of the heart muscle cells. This affects how sodium ions move into the heart muscle and, in turn, affects how the electrical signals that cause the heart to contract and relax are transmitted.

It does not affect the structure of the heart but affects the electrical signalling in the heart.

As it affects the electrical signalling, it is often diagnosed through an ECG and often shows a typical pattern on an ECG. However, as it can be an autosomal dominant genetic condition, a genetic test might also be used to look for the mutation that causes the condition.

There are two types of Brugada syndrome, types 1 and 2. Not everyone with Brugada syndrome will have symptoms, and some will have symptoms when triggered by something such as a high temperature or dehydration. Symptoms can include chest pain, palpitations and breathlessness. It can also cause a life-threatening heart rhythm (ventricular arrhythmia). If someone is at risk of arrhythmias it may be recommended that they have an ICD fitted.

*Channelopathy refers to conditions that are caused by problems with ion channels or proteins that regulate these channels.

Where the normal electrical messages that cause the heart to contract are blocked or slowed by the fibres that conduct the signal. This means that the heart contracts more slowly than usual. This reduces the amount of blood that leaves the heart and circulates to the body.

The Bundle of His is a group of muscle fibres in the heart, which sits in the septum – the muscular wall between the left and right ventricles. It plays an important role in the cardiac cycle (the cycle that controls the heart beat by sending electrical messages through the heart).

The Bundle receives electrical messages from the atrioventricular node (or AV node), which it then conducts and spreads to the left and right bundle branches. This message then spreads to small muscle fibres in the ventricle walls (called Purkinjie fibres) which causes the ventricle walls to contract. This forces blood out of the ventricles in systole.

For more information about the cardiac cycle see our page 'what is cardiomyopathy'

A form of treatment used for people with narrowed coronary arteries and for whom angioplasty or having stents inserted is not possible. It involves having a vein from another part of the body (such as the arm or leg) removed and using it to replace a section of the coronary artery that is blocked. This then allows the blood to move freely through the new section of artery.

A group of medications used to treat some symptoms of cardiomyopathy, by reducing the force at which the heart contracts. Some types are used to reduce blood pressure (hypertension) by reducing the stiffness of the arteries, which helps the heart to fill with oxygenated blood. An example of this type is amlodipine. Others are used to reduce chest pain (angina) and arrhythmias. An example of this type is verapamil.

The smallest of the blood vessels, linking together the arteries and veins. Capillaries have thin walls which allow oxygen and nutrients to pass into the cells and organs.

Cardiac arrest is when the output of the heart stops (where ‘cardiac’ means heart and ‘arrest’ means stops). This means when blood stops being pumped out of the heart, it results in breathing stopping, the person losing consciousness and collapsing and, if untreated, the person will die (referred to as ‘sudden cardiac death’). There are a number of causes of cardiac arrest.

A common cause of cardiac arrest is ventricular fibrillation (or VF). VF is when a series of abnormal impulses, coming from many parts of ventricle walls, interrupt the electrical signalling in the heart. This causes the ventricles of the heart to contract in an uncoordinated way, and ‘quiver’ (or ‘fibrillate’) rather than contract normally. This means that the heart can’t pump blood out of the ventricles. In VF, a shock to the heart (for example, from an ICD or AED) can interrupt these abnormal ‘chaotic’ electrical signals (literally ‘de-fibrillating’ or stopping the fibrillation) and restore sinus rhythm (normal heart rhythm). This is like an electrical shock ‘re-setting’ the heart’s normal rhythm.

If someone has an ICD, this will detect the VF, and will give a shock when appropriate. If an AED is used, the AED will detect when VF is happening and will give a shock. As it is important to keep blood, and oxygen, flowing through the heart, CPR (cardiopulmonary resuscitation or heart compressions and ‘rescue breaths’) should be given until the AED arrives.

Asystole is when the heart stops beating and there is no electrical activity in the heart. This means that the heart’s ventricles cannot contract and so no blood is pumped out by the heart. (This is seen as a flat line on an ECG.) Asystole is treated by CPR which manually forces blood through the heart and helps to keep oxygen circulating through the body. This keeps the blood circulating until emergency medication can be given to help restore the heart’s electrical activity. In this cause of cardiac arrest, an electrical shock (from an ICD or AED) will not work as these devices only work if there is some electrical activity within the heart itself. 

A cardiac arrest is different from a heart attack.

This is a medical procedure where a small sample of heart muscle is removed using a catheter (long flexible tube) with small pincers at the end. This sample of muscle is then sent to a laboratory for tests. This procedure is not done routinely but may be used to help confirm a diagnosis of cardiomyopathy, or to confirm conditions such as myocarditis (inflammation of the heart) or amyloidosis (a condition where a protein called ‘amyloid’ builds up in the heart and affects how well the heart works).

A test sometimes used in the diagnosis of cardiomyopathy. It involves taking X-rays of the coronary arteries during a coronary angiography. It can be used to see the structure and function of the heart.

This is the typical heart beat as seen on an ECG (electrocardiogram). An ECG records the electrical activity of the heart during the cardiac cycle (how the blood flows through the heart).

The ‘cardiac complex’ follows the electrical messages that control the heartbeat through the atria and ventricles of the heart, which are transmitted via the ‘Bundle of His’ and ‘Perkinje fibres’. These electrical messages cause the ventricles to contract and pump blood out of the heart (either to the lungs or to the rest of the body).

During this cycle, the electrical signals recorded on the ECG change according to the different parts of the cycle. Each letter (P, Q, R, S and T) represents a different and distinct stages of the pathway.

The P wave represents the depolarisation of the atria and the start of the atria contracting.
The Q wave represents the depolarisation of the septum and the start of the ventricles contracting (from Q to S).
The R wave represents the electrical message through the main part of the ventricle wall.
The S wave represents the depolarisation of the Purkinje fibres.
The T wave represents the repolarisation of the ventricles, when the ventricles start to relax.

Part of the complex, the QRS complex, follow the electrical messages through the ventricles and represents the upwards and downwards patterns on the ECG which happens when the ventricle contract and relax.

Commonly known as a heartbeat, this describes how the blood flows through the heart during the double circulation system. The two phases of the cycle are diastole and systole.

This is one of three types of muscle found in the human body. Cardiac muscle (myocardium) is unique: it is highly specialised and only found in the heart. It is made up of individual muscle cells called myocytes, and works constantly, never tires and never needs to rest. Also known as heart muscle.

This is the amount (volume) of blood that is pumped by one of the ventricles over the course of one minute. This is determined by the heart rate (number of beats per minute) and the stroke volume (amount of blood pumped out at each heart beat).

Cardiac remodelling is a term that refers to changes in the heart’s size and shape that occur in response to cardiac disease or cardiac damage. When doctors talk about “remodelling,” they are usually talking about the left ventricle, though occasionally this term is applied to other cardiac chambers.

Doctors can assess whether cardiac remodelling is present, and can follow the extent of remodelling over time, with imaging studies that allow them to assess the size, shape, and function of the left ventricle.

A type of pacemaker that helps to resynchronise (coordinate) the electrical messages between the two ventricles of the heart to start the contraction of the heart muscle. These are often used to control the symptoms of heart failure by improving the effectiveness of the heart’s pumping action.

This is also known as biventricular pacing as it stimulates both ventricles of the heart. It is often used when someone has dilated cardiomyopathy (DCM) and commonly left bundle branch block.

Disease of the heart muscle. This is a general term for a number of conditions (or diseases) that all affect the heart muscle, and affect the heart’s ability to function normally.

A general term for disease of the heart or blood vessels (the cardiovascular system). This includes stroke and coronary heart disease.

The heart and blood vessels.

A procedure used to get the heart back into normal rhythm. This is used for people with arrhythmias such as atrial fibrillation. This procedure is done in hospital under a general anaesthetic, and either uses drugs or an electrical shock to get the heart back into a normal rhythm.

See 'ablation'.

This is the name for a group of conditions caused by abnormalities or mutations in the ion channel of cell membranes (which control how messages are relayed between cells). These conditions can be present from birth, or can develop later on. It is thought that some channelopathies can affect the heart and may cause cardiomyopathy, such as Brugada syndrome and Long QT syndrome.

Commonly known as angina, this pain is due to a reduced flow of blood and oxygen to the heart muscle. Cardiologists may ask about feeling ‘chest pain’ or ‘chest tightness’ as it is sometimes difficult to describe these unusual feelings in the chest. This might happen during exercise or while resting. Some people with cardiomyopathy may experience these chest pains.

How DNA is organised in the nucleus of cells. Each chromosome contains DNA and protein, wrapped up into a ‘double helix’ (two twisted strands). Human cells contain 46 chromosomes, in 23 pairs. 22 of these pairs are matching and called autosomes (numbered 1 to 22). The 23rd pair determines the gender of the person and is called the sex chromosomes: if they are matching (called XX) the person is female, and if they are not matching (called XY) the person is male. DNA is the genetic material that determines every individual’s characteristics, and is passed from parent to child.

This refers to a condition that is present from birth (or develops before birth), although it does not describe the cause of the condition. Congenital conditions can be genetic or caused by physical or environmental factors. Some heart conditions are described as congenital, and this usually refers to conditions such as a hole in the heart or valve disease

Although this term is often used to mean heart failure, this refers to a particular stage in heart failure when fluid has started to build up around the heart and in the lungs (and causes ‘congestion’).

You can read more about the stages of heart failure here

A procedure used in the diagnosis and treatment of some heart conditions. It involves a long tube called a catheter being inserted into a blood vessel, often at the top of the leg, which is then fed up to the heart and coronary arteries. A dye is injected into the catheter so that X-rays can be done (called coronary angiograms) to see the structure of the blood vessel, and whether there are any blockages. This procedure may be done to diagnose angina or coronary heart disease.

The arteries that supply the chambers of the heart with blood. The heart needs its own supply of blood in order to get the oxygen it needs to function. This is provided by the left and right coronary arteries. Note: these are not the arteries that the heart pumps blood through (the pulmonary and aorta).

A condition where the coronary arteries that supply the heart with blood become narrowed or blocked, reducing the amount of oxygen getting to the heart. This can cause angina, heart attack and heart failure.

A technique used to help save someone’s life if they stop breathing or their heart stops beating. It involves giving ‘rescue breaths’ and chest compressions to keep blood circulating around the body. CPR on its own cannot ‘restart’ the heart, but it is vital until the paramedics arrive and can give an electrical shock to restart the heart or get it back in a normal rhythm. Some local communities also have automated external defibrillators (or AEDs) which can be used by someone giving CPR to shock the heart.

A machine that delivers an electric shock to the heart in order to correct an abnormal heart rhythm. This may be used in a procedure called cardioversion.

Blood that has a low level of oxygen, which is returning to the heart from the cells and organs of the body (where the oxygen it was carrying has been used up). See also oxygenated blood.

Part of the cardiac cycle where the chambers of the heart are relaxed, which allows them to fill with blood.

A type of medication used to treat arrhythmias such as atrial fibrillation as it can reduce the heart rate. Reducing the heart rate allows the heart chambers time to fill with blood, so that it works more effectively.

Becoming wider or larger.

A type of cardiomyopathy where the muscle of the left ventricle becomes enlarged (or dilated) and stretched. This makes the wall of the ventricle bigger but thinner, and so the muscle is weaker and less able to pump blood out of the heart.

We have lots more about information about dilated cardiomyopathy (DCM) on the cardiomyopathy information section of our website.

A type of medication often used to treat symptoms of cardiomyopathy. Diuretics help to reduce the build-up of fluid on the lungs or in the ankles by encouraging the kidneys to get rid of water as urine. Some diuretics can also be used to reduce blood pressure.

The material that makes up genes. It is made up of long strands of 4 different chemicals which are arranged in many different ways to tell the cell what type of cell to become and what function to do in the body (for example, a skin cell, a heart cell or a muscle cell). The long DNA strands are wound tightly into chromosomes. Human cells have 46 chromosomes, in 23 pairs. Our DNA determines all of our characteristics, and is passed from parent to child. This is how we inherit characteristics from our parents. See also genetics

How the blood flows in the human circulatory system. It is called ‘double’ because for each circulation of the body, blood goes through the heart twice: once to be pumped to the lungs to pick up oxygen and once to be pumped to the rest of the body.

Muscular dystrophy (MD) is a genetic condition that affects the production of proteins that make up muscle, and so causes loss of muscle and progressive muscle weakness. It is sometimes referred to as a ‘muscle-wasting condition’. There are several types of MD, including Duchenne.

Duchenne muscular dystrophy is a severe type of MD, which affects around 2,500 people in the UK. It is genetic condition and is linked to the ‘X’ chromosomes. It usually only affects boys.

DMD is caused by a lack of a protein called dystrophin, which is normally found skeletal and smooth muscle, as well as the heart muscle. The lack of this protein causes the muscle fibres to be replaced with fatty tissue. This means that the muscle weakens over time. Initially, the person will have problems running, jumping and walking up stairs. This can progress so that walking is slowed and becomes difficult, and they are likely to need to use a wheelchair.

As the protein dystrophin is usually present in heart muscle, a lack of this protein in Duchenne MD can cause problems with the function of the heart: thinning and enlargement of the left ventricle wall, leading to dilated cardiomyopathy (DCM), heart failure and arrhythmias. When this happens, the condition is treated as normal for DCM, depending on the symptoms experienced.

Although there are no cures for muscular dystrophy, treatment such as steroids can help to control symptoms and reduce the progression of the condition. It is also recommended that anyone diagnosed with DMD have regular heart function tests to identify and treat the symptoms of cardiomyopathy.

Read more on Muscular Dystrophy UK.

This is where a blood clot forms in the deep veins within the leg. Although it is rare, the clot can travel to the heart and block an artery in the lung.

The medical term for breathlessness or shortness of breath.

This is an abnormal or irregular rhythm of the heart, which can be too fast, too slow or irregular. This is another name for arrhythmia.

A test that looks at the heart’s rate and rhythm by recording its electrical activity. It involves having small electrodes attached to the skin, on the chest, arms and legs, which detect the electrical signals produced by the heart when it beats. The results of the ECG are seen on a computer image called an electrocardiogram.  

An ECG is often used when diagnosing heart conditions such as cardiomyopathy, and can detect arrhythmias or when the supply of blood to the heart is blocked or reduced. A ‘stress ECG’ or ‘exercise ECG’ is done during exercise (such as on an exercise bike or a treadmill) to check how the heart when under pressure. Holter monitors are used when an ECG is done continuously over one or two days (also called ambulatory ECG).

A type of scan that looks at the structure and function of the heart. It uses ultrasound – high frequency sound waves – to create echoes that are turned into an image. An echo is often used as part of the diagnosis of cardiomyopathy as it can look at the structure of the heart and detect any areas that are dilated or thickened.

A measure of the percentage of blood that is pumped out (or ‘ejected’) from the heart when the left ventricle contracts, compared to the amount of blood within the ventricle. It is one of a number of way of assessing how effectively the heart is pumping, and can be used to see how well the heart is working over a period of time. An ejection fraction in a healthy heart is usually around 50 – 60% (and not the 100% that might be expected). Although an ejection fraction reading is a common measure, it is worth noting that it is only one of a number of tests used, and it doesn’t always correspond with the severity of an individual’s symptoms.

A type of test that looks at the electrical activity of the heart, often used for people with arrhythmias. The test involves having a long tube called a catheter inserted into a blood vessel, often through the groin, which is then fed up to the heart.

Electrical signals are then sent through the catheter to the heart which makes it beat at different rates, which is recorded. This can be used to find where in the heart arrhythmias are coming from. The results from these tests can determine treatment options such as medication, implanted devices, ablation or surgery.

An infection of the heart that affects the endocardium (the inner lining of the heart). This infection is caused by a bacteria which enter the heart through the blood stream and stick to the inside surface of the heart. For example, this could include bacteria causing tooth decay, and this can be a reason that it is important to have good oral hygiene (looking after your teeth and gums) and see your dentist regularly.

In a healthy heart, bacteria will usually pass through the heart safely, but if the heart is damaged (for example, if the valves are damaged) the bacteria may become trapped. This infection can affect the flow of blood through the heart, and can lead to heart failure. Endocarditis can be serious, and needs urgent medical treatment.

The inner membrane lining the heart, which covers the atria and ventricles, and forms the heart valves.

Entresto is a new drug used to treat the symptoms of heart failure. It is a combination of an ARB (angiotensin II receptor blocker) called valsartan and an anti-hypertension drug called sacubitril.

This drug was tested during the Paradigm-HF clinical trial in 2014. In this trial it was compared to the ACE inhibitor (angiotensin converting enzyme inhibitor) enalapril. The research trial found that Entresto use resulted in significant reductions in the number of people admitted to hospital, and number of people dying, due to heart failure.

Entresto works by increasing the level of specific proteins in the blood which encourage the widening of blood vessels, and lowering blood pressure by reducing sodium levels and helping to keep the arteries relaxed.

Entresto was licenced for use in the UK by NICE (National Institute for Health and Care Excellence) in April 2016. It is available as a treatment option in people for whom the standard treatment of ACE inhibitors and beta blockers are not fully effective.

In order to have this treatment, the NICE guidelines state that you should:

• have New York Heart Association (NYHA) class II to IV symptoms;
• have a left ventricular ejection fraction of 35% or less; and
• be taking a stable dose of ACE inhibitors or ARBs.

Entresto should not be taken during pregnancy or alongside ACE inhibitors or ARBs.

Further research into the effectiveness and possible side effects of Entresto is continuing.

The outer covering of the heart muscle (myocardium).

A type of ECG that is done during exercise such as on an exercise bike or a treadmill. The test looks at how the heart functions during exertion, where the heart is under increased pressure to work.

This is a general term used for when someone loses consciousness due to a lack of oxygen getting to the brain. Often the person will be aware of symptoms leading up to the faint, such as feeling generally unwell, and their vision may become blurred or narrowed. This is different from syncope, which is a sudden loss of consciousness without warning, which can happen in some people with cardiomyopathy.

Extreme tiredness or exhaustion, which can be a symptom of heart failure, and is a symptom of cardiomyopathy.

These are close relatives related by blood: parents, siblings and children. If someone is diagnosed with cardiomyopathy with a genetic cause, it is often recommended that their first degree relatives are also tested for the condition.

This is a way to measure the function of the left ventricle of the heart. Unlike the ejection fraction (which measures and compares blood volumes), fractional shortening measures the diameter of the left ventricle when it is contracted, compared to when it is relaxed.

A relatively new area of science that aims to use genetics to prevent and treat medical conditions. This is still experimental, but could mean that doctors could replace a mutated gene with another gene in order to treat and prevent genetic conditions, instead of using medication or surgery.

The DNA of each chromosome is made up of a number of different genes, each of which codes for a particular characteristic, such as height or hair colour. The genes on a pair of chromosomes control the same characteristics but can act in different ways.

For example, being tall or short, having brown or blond hair. So different forms of a gene can be inherited from the two parents. Genes are sometimes referred to as the basic building block of genetic material.

A change in part of the DNA which causes a change in how the relevant individual gene is expressed. For example, a genetic mutation can cause the development of a disease or condition such as cardiomyopathy. In this case, the disease or condition may be referred to as ‘genetic’.

However, a genetic condition does not necessarily mean that it has been inherited (passed on to an offspring by their parent). In some cases, the gene mutation occurs for the first time in the individual (sometimes referred to as ‘de novo’ or ‘from new’), rather than occurring in their parent and being inherited. However, once a mutation has happened, it can be passed to the next generation (inherited).

The study of genes, genetic variation, physical characteristics and patterns of inheritance. This includes how medical diseases and conditions are inherited.

When the heart’s own supply of blood from a coronary artery is stopped due to a blockage. This can happen due to a narrowing of the artery or a blood clot, caused by coronary heart disease. This results in the heart being starved of blood and oxygen, which affects the functioning of the heart muscle, and can cause that area of muscle to die.

Symptoms of a heart attack include a heavy chest pain, shortness of breath and feeling light-headed. Although heart attacks can be fatal, most are treatable by breaking down the blood clot with drugs and by widening the narrowed or blocked artery. A heart attack is not the same as a cardiac arrest.

When the normal spread of electrical activity from the SAN to the AVN, which controls the contracting of the chambers of the heart, is slowed or stopped. This might mean that there is a slight delay in the messages from the SAN reaching the AVN, or that the messages are completely blocked.

This is a type of arrhythmia, and can cause breathlessness, palpitations, dizziness and loss of consciousness. In some people with serious heart block a pacemaker may be recommended, which sends electrical messages to keep the heart beating at a normal rate.

When the heart fails to pump enough blood, at the right pressure, to meet the body’s needs, due to a reduced ability to function properly. This may happen because the heart muscle is too weak or too stiff to work properly, or when the heart’s valves are damaged. It is usually used to describe the symptoms of shortness of breath, fluid retention (causing swollen ankles and abdomen) and fatigue (caused by reduced oxygen levels).

There are many different causes of heart failure, including coronary artery disease and heart attacks, and it can also be caused by cardiomyopathy. Although the term ‘heart failure’ sounds like it means that the heart is not working, it just means that it isn’t working well enough to meet the demands of the body, and needs extra support to help it function. It is usually treated with lifestyle changes, medication, devices or surgery to help the heart to work more effectively

A sound made by the heart that can be heard through a stethoscope. Some murmurs are harmless, but others can be a sign of a heart condition. An example of a heart murmur is when a small amount of blood flows in the wrong direction through the heart when it contracts, due to the mitral valve not closing properly (see also mitral regurgitation). This can be a symptom of hypertrophic cardiomyopathy with obstruction.

Another name for cardiac muscle.

Individual cells that make up the muscle walls of the heart. These cells are usually arranged in an organised structure, and are branched and connected together so that they are synchronised (work together) when they contract and relax to make the heart pump blood around the body. They communicate by electrical signals which are spread quickly. Also known as myocytes.

The number of times the heart beats each minute. The average heart rate for an adult is 60-100 beats per minute.

Where someone's heart is removed and replaced with the heart from a donor (another person). This is a treatment for people with very advanced heart failure, whose condition cannot be treated completely with other forms of treatment (such as medication).

Stands for hypertrophic obstructive cardiomyopathy, and refers to asymmetrical septal hypertrophy with obstruction.

A way of recording an ECG over a period of time such as a few days, while carrying on with normal activities. The ‘holter’ refers to the ECG device which is worn around the waist or in a pocket, which makes it possible to move and walk around (rather than being connected to a large machine). This may also be referred to as ambulatory ECG.

The medical term for high blood pressure. See ‘blood pressure’.

A type of cardiomyopathy where the muscle of the heart becomes thickened and stiff. This usually affects the left ventricle of the heart, but can also affect the right ventricle. The thickening might affect the apex of the heart (see apical hypertrophic cardiomyopathy), the septum of the heart (see asymmetrical septal hypertrophy), or might affect the whole of the left ventricle (known as symmetrical or concentric thickening).

We have lots more about information about hypertrophic cardiomyopathy (hcm) here

A form of hypertrophic cardiomyopathy (HCM) where the thickened area of muscle affects the whole of the left ventricle evenly, reducing the overall capacity of the ventricle. This can cause an obstruction to the blood flow leaving the left ventricle (see also hypertrophic cardiomyopathy with obstruction).

Means thickening. For example, hypertrophic cardiomyopathy (HCM) is caused by a thickening of the heart muscle.

The medical term for low blood pressure. See ‘blood pressure’.

A form of treatment used to monitor the heart rhythm and give an electric shock to the heart if it detects a dangerous arrhythmia. An ICD is implanted under the skin on the left upper chest wall, and connected to the heart via wires fed into the ventricles.

It is used for people with arrhythmias such as ventricular fibrillation or ventricular tachycardia, or people who are at a high risk of sudden cardiac death. ICDs can also work as pacemakers. Some ICDs are implanted on the left side of the chest and are known as subcutaneous ICDs, as the wire is laid under the skin alongside the breast bone. This type of ICD is not able to act as a pacemaker and therefore won’t be suitable for anyone who needs a pacemaker.

A term meaning 'unknown', which is used to refer to a condition where the cause is unknown. An example of this is idiopathic dilated cardiomyopathy, which is when someone has dilated cardiomyopathy but the cause of this condition is unknown.

When a particular genetic characteristic is passed from parent to offspring.

This is another term for coronary heart disease, where ‘ischaemic’ refers to a lack of blood supply to an organ (in this case where the heart’s own supply of blood is reduced due to a build-up of fatty and calcified substances in the coronary arteries).

Ivabradine is a drug more recently introduced as a treatment for heart failure conditions. It was originally developed as a treatment for angina, receiving its European Medicines Licence in 2005.

Ivabradine has one action, which is to lower the heart rate, and it is categorised as a selective If current inhibitor. This is the current which is found in the sinoatrial node, which is the area at the top of the heart which produces the electrical impulses to make the heart beat regularly. It is sometimes referred to as the hearts pacemaker. The f in the abbreviation, rather strangely, stands for ‘funny’. This is because when it was first discovered its actions were thought to be unusual compared to other known electrical currents in the heart. The If current controls the action of the hearts pacemaker and therefore the rate at which the heart beats. By partially blocking this current ivabradine lowers the heart rate.

See 'Bundle branch block'.

A form of treatment for people with severe heart failure, who may be on a heart transplant list. LVAD is an artificial pump, used to assist the heart to pump blood around the body. It is attached between the left ventricle and the aorta, and helps to draw blood out of the ventricle and pump it out of the heart through the aorta.

The LVAD is powered by a battery, which sits outside of the body and is connected to the device by a lead (called a driveline). Ventricular assist devices can also be used to support the right side of the heart (right ventricular assist device) or, in some cases, used for both sides of the heart (called a biventricular assist device).

a type of cardiomyopathy caused by a problem with how the heart muscle develops in an unborn baby. During development the heart muscle cells do not compact (tightly pack together) as normal which makes the muscle appear spongy. This can affect the electrical signalling in the heart, as well as how the muscle contracts, which affects how the heart works. This condition can lead to complications such as heart failure and arrhythmias, but in other people it may cause no symptoms.

Long QT syndrome is often a genetic condition, although it can also be caused by medications used for other conditions (such as some antibiotics and antidepressants). It affects the proteins that make up ion channels in the myocytes (heart muscle cells). As ion channels are a vital part of how electrical messages are transmitted through the heart, when they don’t work properly, or there are too few of them, it causes problems with the electrical activity of the heart.

How blood flows through the heart as it beats is referred to as the cardiac cycle, and the beating of the heart (when it contracts and relaxes) is controlled by electrical messages sent through the heart muscle. These electrical messages, when recorded on an EEG, form a typical pattern of five waves. These are referred to as P, Q, R, S and T waves, and each corresponds to a particular part of the cardiac cycle. The waves from Q to T corresponds to the electrical messages as they move through the ventricles. In long QT syndrome the length of time from the Q to the T waves are, and the name suggests, longer than normal. This means that the ventricles take longer to recover or ‘reset’ between contractions.

Some people don’t experience any symptoms from Long QT syndrome. However, it can cause loss of consciousness and seizures, when the heart’s rhythm is affected and it cannot get enough blood to the brain, which causes it to be temporarily starved of oxygen. Once the heart rhythm returns to normal, blood flows back to the brain. In some cases, abnormal heart rhythms are persistent, and can cause ventricular fibrillation. In this case, the heart’s rhythm needs to be restored with cardioversion (an electric shock).

Although there isn’t always a trigger for the change in the heart rhythm, it can be triggered by stress, sudden or loud noises or strenuous exercise. Avoiding triggers and eating a potassium-rich diet helps to manage the symptoms of Long QT syndrome. Treatment with medications will also usually be necessary, and a pacemaker or ICD may be recommended to treat any dangerous heart rhythms.

For more about QT see cardiac complex

Lupus is an autoimmune disease. This means that the body’s own immune system is over-active and produces too many antibodies, which attack the body’s healthy cells, tissues and organs. It is not clear what causes lupus, although it might have both genetic and environmental causes. There a many different forms of lupus, and systemic lupus erythematosus (or SLE) is the most severe.

Lupus can have mild or serious symptoms, and affect many organs in the body, such as the lungs, kidneys, skin and joints. People may have times with no symptoms, followed by ‘flare-ups’ where the symptoms are severe. Although there is no cure for lupus, medications can be used to reduce and control symptoms, alongside a healthy lifestyle to reduce any complications from lupus.

Lupus can have complications, and can cause inflammation and damage to the heart. This can lead to cardiovascular diseases (conditions of the heart and arteries) such as pericarditis (inflammation of the lining around the heart), heart valve disease (where the valves become ‘leaky’) and heart attacks.

For more information visit Lupus UK.

This can be a complication of hypertrophic cardiomyopathy when the area of thickening of the heart muscle causes an obstruction to the blood flowing out of the left ventricle. LVOTO may get worse after eating or during exercise, but in some people it happens all time. It is sometimes accompanied by a heart murmur. It can cause chest pain, fatigue and breathlessness.

The MHRA (Medicines and Healthcare products Regulatory Agency) is the organisation that regulates the safety or medicines and medical devices in the UK.

A surgical procedure used to treat mitral regurgitation. The procedure uses a clip to join the two flaps of the mitral valve together to prevent the back-flow of blood. This procedure is not widely used, but may be suitable for people who are unable to have a mitral valve replacement.

A condition where a small amount of blood leaks back through the mitral valve when the left ventricle contracts (instead of flowing through the aorta). This is caused by the mitral valve not closing tightly shut when the ventricle contracts. This can be a complication of cardiomyopathy. In some cases this regurgitation doesn’t cause any symptoms, but it others it can cause symptoms of heart failure and can be associated with palpitations, and arrhythmias. This condition is treated with drugs and sometimes with mitral valve replacement or with a MitraClip.

The valve in the left side of the heart, between the atrium and ventricle. This valve helps to direct the flow of blood from the left atrium into the left ventricle, and prevents the blood flowing back into the atrium when the ventricle contracts. It is also known as a bicuspid valve because it has two cup-shaped flaps. In some people with cardiomyopathy, the mitral valve does not close completely, and blood leaks back into the atrium (mitral valve regurgitation) when the ventricle contracts. This can cause a heart murmur.

A type of surgery to treat mitral valve regurgitation, where the mitral valve is replaced with an artificial valve.

When the mitral valve does not open as widely as normal, which can affect the flow of blood from the left atrium into the left ventricle. This can reduce the amount of blood being pumped through the heart as well as causing the left atrium to enlarge. This can lead to atrial fibrillation.

A type of scan that uses strong magnetic field to create detailed images of parts of the body. An MRI might be used to identify the type of cardiomyopathy that someone has as the structure of the heart can be clearly seen. It can also detect the presence of scar tissue within the heart muscle with may cause dangerous arrhythmias.

This helps to decide on the best treatment options for each person. As this scan uses strong magnetic fields, you may not be able to have an MRI if you have any surgical device, such as a pacemaker or ICD that contains metal. In this case, you may have a CT scan instead.

Another term for a heart attack.

Myocarditis is an inflammation of the myocardium (middle layer of the heart muscle wall). This can have many different causes, and is commonly caused by a viral infection. As well as causing ‘infection’ type symptoms (such as feeling tired, achy and having a headache) it can also cause symptoms of heart failure (such as breathlessness, oedema and arrhythmias).

In some people myocarditis gets better, with or without treatment. However, it can lead to complications and ongoing heart failure. In this case, treatment is used to control symptoms. In some cases, it can cause dilated cardiomyopathy

The thick, muscular heart wall or ‘heart muscle’. The myocardium lies between the pericardium (outer covering of the heart) and the endocardium (inner lining of the heart).

Another name for individual heart muscle cells, which together make up the majority of the heart. Myocytes are usually arranged in an organised structure, and are branched and connected together so that they are synchronised (work together) when they contract and relax to make the heart pump blood around the body. They communicate by electrical signals which are spread quickly.

Blood that is carrying oxygen to the cells and organs of the body. Blood is transported from the heart by the pulmonary artery towards the lungs, where it picks up oxygen (becomes oxygenated). The blood then travels back to the heart by the pulmonary vein before being pumped around the body, where the oxygen is used to fuel the cells and organs. See also deoxygenated blood.

A type of medical device that sends electrical impulses to the heart to stimulate the contraction and relaxation of the heart muscle, and set a normal heart rhythm (sometimes called sinus rhythm). This is used for people who have heart conditions which mean that their heart is unable to set its own pace, or where the heart rhythm is disrupted. A pacemaker may replace or control the electrical signals that the heart would normally generate to help the heart to beat normally.

Some pacemakers work continuously to set the electrical rhythm of the heart. Others detect and control arrhythmias by increasing a too-slow heart rate (bradycardia), slowing down a too-fast heart rate (tachycardia) or synchronising the ventricles to contract together in heart failure conditions. Pacemakers are implanted under the skin on the left upper chest wall, and connected by wires fed into the heart. (See also cardiac resynchronisation therapy devices).

This is care provided to treat the symptoms and side effects of a medical condition. It also includes practical support and help to cope with the social, emotional and psychological impact of having a medical condition. It aims to treat people holistically (their whole life, not just their illness) so that they can achieve the best quality of life they can.

Although this term is often used to describe the care of someone with a terminal illness, or 'end of life' care, it also applies to anyone living with a long-term health condition or disability that limits their life

An awareness of a change in the heart rate and or rhythm. Often the person will be aware of, or can feel, their heartbeat, which can feel like a flutter or can be uncomfortable. Palpitations can happen suddenly, and are usually short-lived. They are normal at certain times, such as during exercise or periods of stress. However, if they appear to happen spontaneously, this can be a symptom of cardiomyopathy. 

A double-layered membrane or ‘sack’ that encloses the heart, which is filled with pericardial fluid. It holds the heart in place within the chest cavity and allows it to move as the muscle contracts and relaxes as the heart beats.

The period of time just before, during and following the birth of a baby.

See also: peripartum cardiomyopathy (PPCM)

A type of dilated cardiomyopathy that starts in a pregnant women during the last month of pregnancy or during the six months following birth. This condition is rare, and most women will recover from the condition over time. However, some women are seriously affected, and have severe heart failure.

Read more about Peripartum cardiomyopathy (PPCM) 

The main artery that transports blood away from the right ventricle towards the lungs, where it becomes oxygenated.

Pulmonary hypertension is high blood pressure (‘hyper-tension’) in the blood vessel that transports blood to the lungs (‘pulmonary’). This increased pressure is caused when the pulmonary artery, which carries blood from the right ventricle of the heart to the lungs, become thick and stiff. The artery cannot expand to allow the blood to flow easily and the flow is reduced. This, in turn, makes it harder for the right ventricle to pump blood out of the heart into the artery. This puts extra pressure on the right ventricle, which has to work harder, and means that the heart becomes weaker. Pulmonary hypertension can develop into heart failure.

Pulmonary hypertension can be caused by problems such as:

• thickening of the small branches of the pulmonary artery (for example, due to congenital heart problems, high blood pressure in the liver and some medications);
• persistent pulmonary hypertension in newborn babies;
• heart disease in the left side of the heart (such as mitral valve problems or problems in the left ventricle;
• lung disease that reduce the levels of oxygen in the blood that cause the arteries to narrow (such as chronic obstructive pulmonary disease or obstructive sleep apnoea);
• blood clots that cause narrowing or blocking of the pulmonary arteries; and
• less common causes such as sarcoidosis.

Oedema is an excessive build-up of watery fluid in areas of the body. Pulmonary oedema is a build-up of fluid on the lungs.

This build-up of fluid can be caused by heart failure because the heart is unable to pump effectively which causes increased pressure in the blood vessels carrying blood to the lungs. In turn, this causes fluid to be pushed out of the blood vessels and into the alveoli (air sacs) of the lungs. Symptoms of pulmonary oedema can include difficulty breathing, noisy or wheezy breathing, shortness of breath, difficulty breathing when lying down flat (called 'orthopnoea') and coughing up blood.

The main vein that transports blood from the lungs into the left ventricle of the heart, before being pumped out to the rest of the body.

When blood flows the wrong way through a heart valve because the valve does not close properly. (See mitral regurgitation.)

A type of cardiomyopathy where the heart muscle becomes stiff and cannot relax properly. This makes it harder for blood to flow into the heart and fill the chambers.

An area of specialised heart muscle cells which generate and conduct the electrical impulses which makes the heart muscles contract and relax (or ‘beat’). The SAN is sometimes referred to as the heart’s ‘pacemaker’.

Sarcoidosis is an autoimmune condition –a condition of the immune system, where the normal immune response doesn’t work properly, is overactive, and attacks the body’s healthy cells and organs. This causes inflammation and white blood cells to clump together and form granulomas (small lumps). These lumps can form anywhere in the body, and usually affect the lungs and skin. However, they can occur in and affect any of the organs. What symptoms occur depends on where in the body the granulomas are. For many people, their symptoms will get better and they won’t need any specific treatment. However, for some their symptoms are severe and long-lasting (and referred to as chronic sarcoidosis) as the granulomas can stop the organs working properly.

Where sarcoid granulomas occur in the heart it is referred to as cardiac sarcoidosis. The granulomas usually occur in the ventricles, septum and papillary heart muscle (muscles in the ventricles which attach to the atrioventricular valves) and, less often, in the atria. They can also occur within the heart muscle, which can affect the electrical activity of the heart and cause arrhythmias and heart block. It can also cause dilated cardiomyopathy and heart failure. When the condition affects the lung (called pulmonary sarcoidosis) that can also affect the function of the heart due to pulmonary hypertension.

For more information contact The Sarcoidosis Charity (opens new window) or the British Lung Foundation (opens new window).

The area of muscle in the middle of the heart, which separates the right and left side of the heart.

The normal rhythm of the heart. The electrical messages start in the SAN, pass to the AVN as the atria contract, and then spread through the walls of the ventricles so that they contract.

A type of muscle found in the human body. This muscle can be found attached to bones, under the skin and in the diaphragm. Skeletal muscle is consciously controlled, for example using your leg muscles to walk or run.

A small mesh tube that is used to expand a narrow or blocked artery during a procedure called coronary angioplasty following a heart attack or for angina.

A condition where the supply of blood to the brain is suddenly stopped, and the brain becomes starved of oxygen. This can cause an area of the brain to be damaged or to die. Strokes can happen due to a bleed in the brain, but most happen when a blood clot enters the blood stream to the brain. Strokes can be a complication of cardiomyopathy if a blood clot forms due to conditions such as atrial fibrillation.

This is the amount (volume) of blood that is pumped out of the heart at each beat. Together with the heart rate this gives a cardiac output.

Where someone dies suddenly due to a cardiac cause. If someone is at risk of sudden cardiac death, for example due to a life-threatening ventricular arrhythmia, they may be fitted with an ICD.

This is a general term for types of arrhythmia (abnormal heart rhythms) where the heart beat is faster than normal. 'Supraventricular' refers to the location: the arrhythmia happens above the ventricles. 'Tachycardia' means that the heart is beating too fast (compared to bradycardia where the heart beats too slowly). An example of a supraventricular tachycardia is atrial flutter.

This is a form of treatment for hypertrophic cardiomyopathy (HCM) where the area of thickened heart muscle causes an obstruction to the blood flow out of the ventricle (sometimes referred to as left ventricular outflow tract obstruction (LVOTO)). This is a type of open heart surgery where part of the thickened muscle is removed to reduce the obstruction.

Part of the cardiac cycle where the muscle walls of the chambers of the heart contract to pump blood out of the heart.

This is a condition where the leaflets (flaps) of the mitral valve of the heart severely obstruct the flood of blood out of the left ventricle due to the thickening of the septum (area of the muscle in the middle of the heart). This obstruction is called left ventricular outflow tract obstruction or LVOTO. This happens during systole of the left ventricle (when the ventricle contracts to pump blood out) and the leaflets of the mitral valve move and obstruct the blood flow out through the aorta. This condition can happen in people with hypertrophic cardiomyopathy (HCM).

An abnormally fast heart rate, usually above 100 beats per minutes in an adult. Although the heart beats faster at certain times (such as during exercise) when it beats abnormally fast without reason, it may be due to a problem with the electrical messaging in the heart which could lead to complications such as a cardiac arrest.

A type of cardiomyopathy where the heart becomes temporarily enlarged and the heart muscle becomes weaker. This condition is often found to happen in individuals after periods of extreme psychological stress (and is sometimes described as stress-induced cardiomyopathy).

This type of cardiomyopathy is often reversible with time. It is named after a form of Japanese octopus fishing pot (where ‘tako’ means octopus and ‘tsubo’ means pot) as the shape of the left ventricle is said to look like the shape of this pot.

The valve in the right side of the heart, between the right atrium and right ventricle. This valve helps to direct the flow of blood from the right atrium into the right ventricle, and prevents the blood flowing back into the atrium when the ventricle contracts. It is called ‘tricuspid’ because it has three cup-shaped flaps.

A test that can be used to see whether an individual has LVOTO. One way of doing this is by attempting to forcefully breathe out while keeping the mouth closed and pinching the nostrils closed. This creates pressure in the chest which simulates exertion (such as when doing physical exercise).

These are areas of muscle or blood vessels that form 'flaps' which ensure that blood flows in the correct direction (and does not flow 'backwards').

The heart has four valves:

• the mitral valve controls the flow of blood between the left atrium and left ventricle,
• the tricuspid valve controls the flow of blood between the right atrium and right ventricle,
• the aortic valve controls the flow of blood leaving the left ventricle into the aorta; and
• the pulmonary valve controls the flow of blood leaving the right ventricle as it is pumped to the lungs.

Veins also contain valves. The blood carried in the veins is returning to the heart from the body and lungs, and is under low pressure. The valves in the vein ensure that blood moves forward towards the heart and doesn't flow backwards.

A type of blood vessel, which transports blood towards the heart from the lungs and from the body. Blood returning to the heart through the veins is under low pressure so the veins have valves in them to prevent blood flowing backwards.

Two large veins that carry deoxygenated blood from the body back to the right atrium of the heart. The superior vena cava transports blood from the head and arms and upper body. The inferior vena cava transports blood from the lower body and legs.

The two chambers at the bottom of the heart with receive blood from the left and right atria. Blood leaves the left ventricle through the aorta towards the body, and leaves the right ventricle through the pulmonary artery towards the lung.

A type of arrhythmia where the contraction of the ventricles is uncoordinated, and they ‘quiver’ rather than contract normally, so blood is not pumped out of the heart effectively. This condition is life-threatening and requires urgent treatment with a defibrillator.

A type of arrhythmia that starts due to abnormal electrical activity in the ventricles, where the heart contracts abnormally quickly (over 100 beats per minute).

This is a drug which can be used to treat high blood pressure, angina and fast abnormal heart rhythms, particularly those coming from the upper chambers of the heart. In cardiomyopathy it is commonly used in the treatment of left ventricular outflow tract obstruction, due to hypertrophic cardiomyopathy. It is part of a group of drugs known as a ‘calcium channel blockers’.

A type of muscle found in the human body. This muscle can be found in the digestive tract, respiratory system and in blood vessels. It is automatically controlled (without having to think about it), for example when food moves through your digestive tract.

Wolff-Parkinson-White (WPW) syndrome is a congenital heart condition - this means that it is present at birth, although symptoms may not occur until adulthood.

In WPW an extra electrical connection between the right atria and the ventricles of the heart is formed by a strand of heart muscle developing while the baby is in the womb. It is not clear why this happens in some babies, but the extra connection means that the usual pathway of electrical messages that control the heartbeat, via the AV node, are bypassed. This can cause a ‘short circuit’ and the electrical messages go around in a loop – causing the heart to beat too fast (called supraventricular tachycardias or ‘SVT’) or in a disorganised way (atrial fibrillation).

WPW doesn’t always cause any symptoms, and some people only have infrequent or minor symptoms. Many SVTs are short-lived and harmless, and may not need specific treatment. However, some SVTs cause palpitations, dizziness, breathlessness and chest pain. Although they usually only last for a short time (seconds or minutes) although it can go on much longer. However, if the person experiences atrial fibrillation it can be life-threatening. WPW can be associated with sudden cardiac death, although this is not usually due to atrial fibrillation.

Treatment, including medication, ablation, or surgery may be used to stop prolonged episodes of SVT, or to control and prevent future episodes of SVT and atrial fibrillation.