Dilated cardiomyopathy: what it is, symptoms, causes and treatment

The NHS describes cardiomyopathy as a general term for diseases of the heart muscle in which the walls of the heart chambers have become stretched, thickened or stiff. In dilated cardiomyopathy the muscle walls become stretched and thin, so they cannot squeeze (contract) properly to pump blood around the body.

BHF explains that the left ventricle is almost always affected, and over time the right ventricle can be too. With DCM, the enlarged muscle walls give the heart a rounder shape instead of its usual cone shape. Cardiomyopathy UK says the condition itself may improve with treatment, although ongoing monitoring is important.

BHF says many people living with DCM might not notice any symptoms at first, and that symptoms often develop slowly and can usually be controlled with medication and other treatments after diagnosis. Cardiomyopathy UK explains why each symptom happens.

• Tiredness (fatigue), because less energy is delivered to the tissues when the heart pumps less effectively.

• Breathlessness, as fluid builds up in the lungs.

• Swelling of the feet, ankles, stomach and lower back, from fluid in the tissues.

• Palpitations, a pounding, fluttering or faster-than-usual heartbeat.

• Chest pain.

See a GP if you notice these symptoms, and tell your healthcare team if symptoms get worse over time. For sudden chest pain that feels tight or like squeezing, pain spreading to the arms, neck or jaw, severe difficulty breathing, or if someone has passed out, the NHS says to call 999 and not to drive yourself to A&E.

The NHS says to contact NHS 111 if you are suddenly more short of breath than usual, or have chest pain with feeling sick or a racing, slow, skipping or fluttering heartbeat. BHF notes that DCM can cause dangerous heart rhythms, which is why palpitations and fainting should always be reported.

BHF says that for many people the cause of DCM is unknown. For others, DCM runs in families and is caused by a change (mutation) to one or more genes, which can make them more vulnerable. The NHS lists several factors that can play a role.

• An inherited gene change that makes you more vulnerable (BHF, NHS).

• A heart valve problem or congenital heart disease (BHF, NHS).

• A viral infection that causes inflammation of the heart muscle (BHF, NHS).

• A heart attack (BHF).

• Uncontrolled high blood pressure (NHS).

• Drinking too much alcohol or using recreational drugs (BHF, NHS).

• Some cancer medications (BHF).

• Diseases of tissues or blood vessels such as sarcoidosis, amyloidosis, lupus and vasculitis, or muscular dystrophy (NHS).

• Pregnancy: peripartum cardiomyopathy is rare and can develop during pregnancy or within 3 months of birth (NHS).

BHF says your doctor might suspect DCM if you have symptoms, a heart murmur, or a family member with DCM. They will usually refer you to a cardiologist, and the most common tests are listed in the table.

BHF says there is no cure for DCM but most symptoms can be controlled by medication and other treatments to help you live your normal life. The type of treatment depends on your symptoms, whether the cause is known and whether you have developed complications. Cardiomyopathy UK says treatment may include medication, devices, surgery or lifestyle management, and is individualised.

The NHS says people with DCM are at greater risk of heart failure, and also of heart valve problems, an irregular heartbeat and blood clots, so you need regular appointments to monitor the condition.

BHF says DCM can cause arrhythmias such as atrial fibrillation, ventricular tachycardia and heart block. People who develop an arrhythmia might need a small implantable device fitted under the skin of the chest: an implantable cardioverter defibrillator (ICD), which delivers a shock to restore a normal rhythm if it becomes dangerous, a pacemaker, or a combined device. In rare cases where devices and medicines have not worked, a heart transplant may be considered, and some people need a left ventricular assist device (LVAD) while waiting.

BHF says DCM is sometimes caused by a gene change that can be passed on through families. If your healthcare professional thinks you have DCM you may be offered a genetic test. If a faulty gene is found, they may ask to talk to your close relatives, because they may also have inherited it.

If you are a parent, sibling or child of someone who has DCM, BHF recommends being seen at a specialist inherited heart conditions clinic for an assessment and a discussion of genetic testing. The BHF Genetic Information Service offers information and support.

BHF says many people with DCM feel fine and have little or no symptoms, and those with symptoms find they are managed well with treatment and can have a good quality of life, although some people have symptoms that get worse over time.

On practical questions, BHF says you should be able to continue to work, but may not be able to do manual jobs that involve strenuous activity. You should be able to enjoy most activities but not some competitive sports and high intensity exercise, and you should be able to continue to drive, although you may not be able to drive a lorry, bus, HGV or commercial passenger vehicle, so check with your healthcare professional or the DVLA. It says having a healthy lifestyle can help reduce the effects of DCM symptoms and lower the risk of other health issues, and the NHS lists drinking too much alcohol and recreational drug use as factors that can play a role in DCM, so it is sensible to discuss alcohol and recreational drug use with your healthcare team.

The NHS says dilated cardiomyopathy can affect both children and adults, and that peripartum cardiomyopathy is a rare form that can develop during pregnancy or within 3 months of the baby's birth. Cardiomyopathy UK describes a child diagnosed at just 6 weeks old in a patient story. BHF recommends that a parent, sibling or child of someone with DCM is seen at a specialist inherited heart conditions clinic.

On the NHS, a GP arranges an ECG and blood tests and refers you to cardiology, where an echocardiogram, MRI and genetic tests are arranged. Treatment is led by cardiology and heart failure teams, with inherited heart condition clinics for family screening.

Some people choose private cardiology to get an echocardiogram or MRI sooner. The tests and treatments are the same. Because DCM needs lifelong monitoring, ask who will review your medicines and when your next scan is due, and keep your GP informed.