Cardiomyopathy

What is cardiomyopathy?

Cardiomyopathy is a general term for diseases of the heart muscle, where the walls of your heart chambers become stretched, thickened or stiff. This makes it harder for your heart to pump blood around your body, and it can affect people of any age.

Symptoms of cardiomyopathy

Cardiomyopathy doesn't always cause symptoms, some people are only diagnosed after a routine test or because a close relative has been diagnosed. When symptoms do appear, they can include:

• feeling short of breath, whether resting or after activity
• feeling unusually tired, or finding you can't exercise as well as you used to
• heart palpitations, or feeling your heart beating irregularly, or too fast
• chest pain
• swelling in your legs, ankles, feet or abdomen
• dizziness, fainting or almost fainting
• a cough, or coughing up blood
• waking up breathless at night or needing extra pillows to breathe comfortably lying down.

In some cases, the first sign of cardiomyopathy is sudden cardiac arrest, so it's worth getting any new or worsening symptoms checked by a doctor.

Causes and who is at risk

Most types of cardiomyopathy are inherited, caused by a changed gene passed down from a parent. For many people, though, no cause is ever found. Other things that can cause or contribute to cardiomyopathy include:

• an underlying heart condition, such as coronary artery disease or a previous heart attack
• long-term high blood pressure that hasn't been treated
• heavy, long-term alcohol use, or recreational drug use such as cocaine
• a viral infection that inflames the heart muscle
• autoimmune and connective tissue diseases, such as sarcoidosis, amyloidosis or lupus
• other health conditions, including diabetes, thyroid disease, muscular dystrophy and haemochromatosis (too much iron in the body)
• pregnancy, a rare type called peripartum cardiomyopathy can develop during pregnancy or within 3 months of giving birth
• radiation or chemotherapy for cancer
• a highly stressful event, such as a bereavement, which can trigger a temporary type sometimes called broken heart syndrome.

You may be more at risk if you have a family history of cardiomyopathy, heart failure or sudden cardiac arrest; a personal history of heart attacks; or a body mass index (BMI) over 30.

Are there different types of cardiomyopathy?

Yes, there are several types, and your symptoms and treatment will depend on which one you have.

Dilated cardiomyopathy

This is the most common type. It happens when the heart's main pumping chamber (the left ventricle) becomes stretched and thin, so it can't squeeze properly to pump blood around your body. This raises your risk of heart failure, an irregular heartbeat, heart valve problems and blood clots.

Hypertrophic cardiomyopathy

The heart muscle cells enlarge and the walls of the heart chambers thicken, most often in the left ventricle. This is thought to affect around 1 in 500 people, and most inherit it from a parent. Many people have no symptoms and don't need treatment, but it can still be serious – it's the most common cause of sudden unexpected death in childhood and in young athletes.

Restrictive cardiomyopathy

This involves the walls of the heart chambers becoming stiff, so the heart can't fill up with blood as it should. It’s a rare type, most often diagnosed in children, though it can develop at any age.

Arrhythmogenic cardiomyopathy (ACM)

Also called arrhythmogenic right ventricular cardiomyopathy (ARVC), ACM is where the heart muscle cells die and are replaced with fatty and fibrous scar tissue, and the heart walls become thin and stretched. This usually causes heart rhythm problems, and it can affect teenagers and young adults.

Other and rarer types

These include left ventricular non-compaction, where part of the heart muscle has a spongy appearance instead of compacting normally, and broken heart syndrome (takotsubo cardiomyopathy), a temporary condition triggered by a surge of stress hormones after events such as bereavement or major surgery, that is usually reversible and unlikely to happen again.

How is cardiomyopathy diagnosed?

Your doctor will start by asking about your symptoms and your family's medical history, since many types of cardiomyopathy run in families, and then examine you. If they think you might have a heart condition, they'll refer you to a cardiologist (a heart specialist) for further tests, which may include:

• Blood tests: This are to check your general health and look for specific markers of heart strain
• An electrocardiogram (ECG): A painless recording of your heart's electrical activity using sticky pads on your chest, which takes just a few minutes
• An echocardiogram (echo): An ultrasound scan showing the structure of your heart and how well it's pumping blood
• A heart MRI scan: This uses magnets and radio waves rather than radiation to build detailed pictures of your heart, you may be asked to avoid caffeine for 2 hours beforehand
• A heart rhythm monitor (sometimes called a Holter monitor): This is worn for 24 to 48 hours or longer, to record your heart's rhythm as you go about your day
• An exercise or stress test: This is to see how your heart copes with physical activity.

If a specific inherited type of cardiomyopathy is found, you might be offered a genetic test to identify the gene responsible. Your close relatives can then be tested for the same gene, so their heart health can be monitored too.

How is cardiomyopathy treated?

Lifestyle changes

There's currently no cure for cardiomyopathy, but treatment can help control your symptoms and slow the condition down. Not everyone needs treatment, some people have a mild form that can be managed with lifestyle changes alone, including:

• eating a healthy, balanced diet that's low in fat and salt
• keeping active with regular, gentle exercise
• getting to, and staying at, a healthy weight
• stopping smoking
• cutting down on or avoiding alcohol
• getting enough sleep, and treating any underlying sleep apnoea
• managing stress
• keeping other conditions, such as diabetes, well controlled.

Medicines

You may also be prescribed medicines, depending on your symptoms and the type of cardiomyopathy you have, such as:

• medicines to control blood pressure
• beta-blockers, to help with an irregular heartbeat or heart failure
• anticoagulants (blood thinners), such as warfarin, to help prevent blood clots
• medicines to correct your heart's rhythm
• medicines to lower cholesterol.

Devices and procedures

If your symptoms are more severe, or medicines alone aren't enough, you might be offered a device or a procedure. These include:

• A pacemaker: A small device that helps regulate your heartbeat if it's beating too slowly
• An implantable cardioverter defibrillator (ICD): Sometimes called a 'defib', a small device with a battery and electronic circuits that can correct a dangerous heart rhythm
• Cardiac resynchronisation therapy (CRT) or a left ventricular assist device (LVAD): Devices that help your heart pump blood more efficiently
• Arrhythmia ablation: A procedure that alters the small area of heart tissue causing a rhythm problem
• Alcohol septal ablation: An injection of alcohol into the heart to reduce thickened muscle in obstructive hypertrophic cardiomyopathy
• Septal myectomy: Heart surgery to remove part of a thickened heart wall, your mitral valve may be repaired at the same time if needed.

A heart transplant is only considered as a last resort if other treatments haven't worked.

When should I see a doctor?

See your doctor if you notice new or worsening symptoms, such as breathlessness, palpitations, swelling or fainting, especially if you have a family history of cardiomyopathy or sudden cardiac arrest. Contact your doctor too if you get side effects from your medicines, or notice any problems with a device such as a pacemaker.

Call 999 or go to A&E straight away if you have chest pain, a fast or irregular heartbeat together with breathlessness, or if you faint or nearly faint.