Dilated Cardiomyopathy


Dilated cardiomyopathy is a condition of the heart muscle. The heart dilates (becomes enlarged) because their muscular walls are weaker and more floppy than normal. This means the heart does not pump blood as strongly as normal.DCM is the most common type of cardiomyopathy. It can affect both children and adults. It is most common in middle-aged men.

What is cardiomyopathy?

Cardiomyopathy is a disorder of the heart muscle. There are four main types:

Dilated cardiomyopathy (DCM) - where the heart dilates (enlarges).
Hypertrophic cardiomyopathy - where the heart muscle becomes thickened (hypertrophied).
Restrictive cardiomyopathy - where the heart muscle cannot relax properly between heartbeats.
Arrhythmogenic right ventricular cardiomyopathy - a rare type which mainly affects the right side of the heart.

(Note: other common heart conditions can cause a dilated heart. For example, coronary heart disease, high blood pressure and heart valve disease. With DCM, the heart dilates because of a problem with the heart muscle itself.)

What causes dilated cardiomyopathy?

Unknown cause
For most people the cause is not known. This is sometimes called idiopathic DCM. Another possibility is that an unknown viral infection may be responsible. About one in four people with idiopathic DCM have a familial (hereditary) form.

Other causes
Some cases are due to known causes. There are many conditions which can cause damage or disease to heart muscle. Most are rare. They include:
Alcohol, After years of heavy drinking, the cells of the heart muscle can become damaged and weakened. Also, heavy drinkers tend to eat poorly (see below).
Drugs and other poisonsSome other chemicals, pesticides and illegal drugs (such as cocaine) have also been shown to weaken the heart muscle and cause DCM.
Poor diet. Deficiency of certain vitamins and minerals, especially vitamin B1 (thiamine), weaken the heart muscle and lead to DCM. This is more common  in people with alcohol dependence who tend not to eat properly.
Inflammation of the heart muscle (myocarditis) is a rare condition which can be caused by various infections. Some people with myocarditis develop DCM as a complication.
Pregnancy and childbirth. Heart muscle inflammation leading to DCM occurs very rarely. It is not known how or why pregnancy triggers this to occur. This is called peripartum cardiomyopathy.
Other diseases which can affect various parts of the body sometimes affect the heart muscle too. DCM sometimes occurs with sarcoidosis, amyloidosis, haemochromatosis, some forms of muscular dystrophy, vasculitis, systemic lupus erythematosus (SLE), polyarteritisnodosa, and Wegener's granulomatosis.

What are the symptoms of dilated cardiomyopathy?

If you only have mild enlargement of the heart, you may not have any symptoms. Symptoms may develop gradually or quite quickly, depending on how quickly the disease progresses. Possible symptoms include the following:

Symptoms of heart failure
Symptoms of heart failure are mainly due to fluid building up in tissues of the lungs and body. This happens because your heart does not pump effectively. Symptoms include the following:
Shortness of breath. In mild cases, you may only become breathless when you exert yourself. Severe heart failure, you may become breathless whilst resting or lying flat.
Swelling of your feet and the lower parts of the legs.

Other symptoms

Palpitations i.e. awareness of your heartbeat which can be fast and/or irregular.
Some people develop chest pains.

How is dilated cardiomyopathy diagnosed?

A doctor may suspect this condition because of:

Your symptoms.
Changes on your electrocardiogram (ECG) - Changes on your chest X-ray. This may show your heart is large or that there is some fluid in your lungs.
An ultrasound scan of the heart, called an echocardiogram. This is a painless test which can confirm that your heart is large and dilated.
Various other tests may be done to find, or exclude, causes of an enlarged heart. If no underlying cause is found then the diagnosis of idiopathic DCM is confirmed. Further tests on the heart may be done to assess the severity of the condition.

How does the condition progress?

This can be difficult to predict. In some cases, the condition remains stable or does not get much worse. Medication may keep the symptoms of heart failure away and your lifestyle may be little affected. In some people, the function of the heart gradually deteriorates. Symptoms of heart failure then get worse and need more intensive treatment.

What are the complications of dilated cardiomyopathy?

An arrhythmia is an abnormal rate or rhythm of the heartbeat. An arrhythmia can come and go or become permanent.This can cause palpitations, dizziness. An arrhythmia called atrial fibrillation is the most common one that develops in people with DCM.

Blood clots
The blood flow through the heart in DCM is slower than normal, this can lead to small blood clots developing within the chambers of the heart. These may travel in the bloodstream and get stuck in arteries of the body. This may lead to a stroke if a clot gets stuck in an artery in the brain, or may get stuck in arteries of limbs leading to problems. The risk of blood clots developing can be reduced greatly by taking an anticoagulant medicine such as warfarin (see below).

Sudden death
Sudden collapse and death without any warning occurs rarely in people with DCM. This is probably due to a severe arrhythmia which may develop suddenly. Medication and/or an implantable defibrillator may reduce this risk.

What is the treatment for dilated cardiomyopathy?

Treatment aims to ease symptoms if they occur and to prevent complications. If you do not have any symptoms, or only mild symptoms, you may not need any treatment. Treatment which may be required includes one or more of the following:

Medication to treat heart failure
Angiotensin-converting enzyme (ACE) inhibitors. Most people with heart failure are prescribed an ACE inhibitor.
A diuretic in addition to an ACE inhibitor. Diuretics work on the kidneys and make you pass out extra urine. This helps to clear excess fluid that builds up in the body.
Beta-blockers have a protective effect on the heart muscle.
Medication to treat arrhythmias for example, amiodarone.
Anticoagulants such as warfarin to prevent blood clotting so easily.

Other types of treatment for arrhythmias

Cardioversion is an option for some types of arrhythmia. Whilst under anaesthetic, you are given an electric shock over the heart. This may revert the rhythm back to normal.
Artificial pacemakers are used in certain types of arrhythmia .

Implantable cardioverter defibrillators (ICDs) are sometimes used in certain situations - especially if you are at risk of developing serious and life-threatening arrhythmias.
Cardiac resynchronization,This is a newer treatment developed to help the changes in your heart muscle. Cardiac resynchronisation tries to improve how the electrical impulses in your heart make it pump more efficiently. This is a small box that is placed just under the skin on your chest wall. It has been shown to improve survival for some. Unfortunately, up to 1 in 3 of people with DCM treated this way see no benefit.


Surgery has also been used to improve how efficiently the heart pumps. This is a rapidly developing area and there are various procedures used.

Heart transplant

In some cases the condition progresses and severe heart failure develops. If this cannot be treated by the methods mentioned here, the only option for treatment is a heart transplant.

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