What is cardiomyopathy?

Information for consumers

Cardiomyopathy is a term that covers a number of conditions that affect your heart muscle. Over time the changes to your heart muscle make it harder for the heart to pump blood to the rest of your body.

Advanced cardiomyopathy can lead to heart failure.

What are the signs and symptoms of cardiomyopathy?

• feeling out of breath, especially when doing physical activity

• feeling dizzy or lightheaded

• chest pain or heaviness

• feeling tired

• an abnormal heartbeat (fast, fluttering or pounding)

• swollen ankles, feet, and legs caused by fluid build-up.

Some people with cardiomyopathy have no signs or symptoms, or their symptoms may be mild. Symptoms usually get worse with time if left untreated but can improve with treatment.

What causes cardiomyopathy?

Cardiomyopathy can be passed on (inherited) from a parent through a faulty gene, known as a mutation. Cardiomyopathy can also be caused by an existing health condition, or an environmental or lifestyle factor. In some people the cause of cardiomyopathy is unknown. Some health conditions or behaviours that are linked to cardiomyopathy are:

• Heart tissue damage from a heart attack or repeated damage to the heart due to extensive coronary artery disease.

• Having uncontrolled high blood pressure for a long time.

• COVID-19 and other infections that cause inflammation of the heart called myocarditis.

• Long-term abnormal heart rhythms.

• Heart valve problems.

• Thyroid conditions.

• The last month, or the months immediately after pregnancy (called postpartum or peripartum cardiomyopathy).

• Other medical conditions that affect body tissues or blood vessels – such as sarcoidosis, amyloidosis, lupus, vasculitis or muscular dystrophy.

• Living with obesity and/or diabetes.

• Drinking too much alcohol over a long period of time, or using recreational drugs (e.g. cocaine or amphetamines).

• Certain medications used to treat other serious medical conditions – such as anthracyclines for cancer treatment and some antipsychotics.

How is cardiomyopathy diagnosed?

Medical and family history Your doctor will ask you about any signs or symptoms that you may have, and about your medical history. If they suspect that you may have cardiomyopathy, they may ask if anyone in your family has been diagnosed with cardiomyopathy, heart failure or cardiac arrest.

Physical examination Your doctor will listen to your heart using a stethoscope. The sounds that your heart makes can help your doctor diagnose cardiomyopathy. Other signs can help your doctor diagnose cardiomyopathy include fluid build-up that causes swelling in your ankles, feet, stomach area, or the veins in your neck.

Diagnostic tests Your doctor may recommend that you have one or more tests to help diagnose cardiomyopathy including:

• blood tests

• a chest X-ray to check if your heart is enlarged or there is fluid in your lungs

• an electrocardiogram (ECG) to record your heart’s electrical activity

• an echocardiogram using sound waves to check the shape of your heart and how well your heart is working

• computed tomography coronary angiogram (CTCA) or cardiac MRI.

You may also need other tests to confirm that you have cardiomyopathy including:

• Cardiac catheterisation – a procedure that checks the pressure and blood flow in the chambers of your heart using a very flexible long thin tube.

• Coronary angiography – a procedure where a dye is injected into your coronary arteries to study blood flow in your heart and blood vessels. This is sometimes done during the cardiac catheterisation procedure.

• Heart muscle (myocardial) biopsy where a very tiny piece of your heart muscle is removed and studied under a microscope to see if there are any signs of changes to the heart muscle.

• Genetic testing to see if you or your family members may have the particular version of the gene (a mutation) that can cause cardiomyopathy.

• Blood tests to investigate specific causes of cardiomyopathy such as viral screening.

• Other tests for rare causes like autoimmune conditions, sarcoid, amyloidosis, and hemochromatosis.

What are the different types of cardiomyopathy?

The most common types of cardiomyopathy are:

What are the complications of cardiomyopathy?

If left untreated, the complications of cardiomyopathy can include:

• Blood clots that form in the chambers of the heart if blood isn’t being pumped through the heart properly. The clots can move into the bloodstream and block blood flow to the body, heart and brain.

• Heart valve problems which can happen if the heart becomes enlarged, and the valves between the heart’s chambers don't meet and close properly, causing blood to flow back into the chambers.

• Heart failure can happen when the heart can't pump enough blood to the body. This can be life-threating if it is not treated.

• Cardiac arrest which happens if the heart suddenly stops beating. This is a medical emergency that can lead to death.

What are the treatments for cardiomyopathy?

The treatment for cardiomyopathy will depend on the underlying cause of the condition. Treatments for cardiomyopathy can help to manage your signs and symptoms, prevent your cardiomyopathy from getting worse and reduce the risk of developing complications. Some treatments include:

• lifestyle changes – moderation of salt and alcohol, cessation of smoking, appropriate physical activity (in consultation with your doctor).

• taking medicines

• medical procedures (including surgeries)

• implanted devices that your doctor may recommend. 

Medicines

Taking medicines can help treat some of the symptoms and effects of cardiomyopathy including removing fluid build-up from the body, preventing blood clots, slowing down your heart rate, and improving the functioning of the heart to improve blood flow. Depending on the type and symptoms of cardiomyopathy, a combination of medications may be prescribed. Some medications used are:

• Angiotensin-converting-enzyme (ACE) inhibitor, neutral endopeptidase (NEP) inhibitor or angiotensin receptor blockers (ARB) – inhibit the renin-angiotensin system to help control blood pressure.

• Beta blockers – block the release of adrenaline to help control blood pressure.

• Anticoagulant, or antiplatelet agent – break down and reduce the ability of the blood to clot to reduce the risk of thromboembolism.

• Diuretics – increase urination to help control blood volume and pressure, and oedema/reduce fluid build-up in tissues.

• Aldosterone antagonists – block the effect of aldosterone to increase urination. These are used for advanced heart failure.

• Calcium channel blockers – limit the amount of calcium that can enters the cells of the heart walls, reducing the contraction (or helping to relax) the heart. 

• Sodium-glucose cotransporter-2 (SGLT2) inhibitors – reduce the amount of glucose in the blood, which reduces blood volume and consequently blood pressure.

Hospital procedures for cardiomyopathy

If required, surgical interventions for cardiomyopathy can include:

• Ablation (septal or radiofrequency) – involves inserting a long, thin tube into a blood vessel in your groin and threading it up until it reaches your heart. Once there, either a chemical or electrode is used to target abnormal heart tissue.

• Myectomy – involves removing part of the septum to improve blood flow through the heart.

• Implanted devices – used to regulate the heart rate (pacemaker) or prevent a life-threatening abnormal heart rhythm (implantable cardioverter defibrillator, ICD).

• In very severe cases, some people may need a left ventricular assistance device (LVAD) or a heart transplant.

The type of treatment you need will depend on the type of cardiomyopathy you have.

Living well with cardiomyopathy

You can help improve the symptoms of cardiomyopathy by:

• following a heart-healthy eating pattern

• avoiding alcohol or reducing the amount of alcohol you drink

• quitting smoking

• making sure your blood pressure is within a normal range

• discussing with your doctor how you can exercise and be physically active every day

• managing stress.

Further information and support

Cardiomyopathy Association of Australia

Our Supporting Young Hearts group

Australian Genetic heart disease registry

Your local cardiac rehabilitation service

What research is the Heart Foundation funding?

The Heart Foundation is funding research to enhance our understanding, diagnosis and management of cardiomyopathy.

Some projects that we have funded include:

• Prof Joseph Selvanayagam investigated the effectiveness of an anti-angina medication on heart muscle thickness in cardiomyopathy patients. Find out more here.

• Dr Geoffrey Wong assessed the link between changes in certain genes and tachycardia-mediated cardiomyopathy. Find out more here.

• Dr Helena Viola’s project focused on developing an innovative cardiac model to test ways to treat and prevent cardiomyopathy. Find out more here.

• Prof Markus Schlaich looked at how the ‘fight or flight’ response is involved with Takotsubo, or broken heart cardiomyopathy. Find out more here.