Dilated Cardiomyopathy

What is dilated cardiomyopathy?

Dilated cardiomyopathy (DCM) is when the heart chambers enlarge and lose the ability to contract. It often starts in the left bottom chamber (ventricle). As the disease gets worse, it may spread to the right ventricle and to the upper chambers (atria). As the heart chamber widens, it becomes weak and doesn't contract well. Eventually, the heart can't pump as much blood as it normally would. This causes fluid to back up in the lungs and build up in the body. This is called heart failure.

DCM is somewhat uncommon, but it's not rare. It affects men more often than women. It tends to occur in adults 20 to 60 years old.

Some types of DCM are reversible. Symptoms may improve with treatment. Other types of DCM are irreversible, and the damage is permanent.

What causes dilated cardiomyopathy?

Many different things can cause DCM. They include:

  • Infections such as HIV, Lyme disease, and Chagas disease

  • Autoimmune diseases such as polymyositis

  • Alcohol abuse

  • Cocaine use

  • Exposure to heavy metals

  • Certain chemotherapy medicines

  • Thyroid disease

  • Diabetes

  • High blood pressure

  • Irregular heart rhythms

  • Response to heart attack or blocked heart arteries (coronary artery disease)

  • Heart valve problems

  • Nutritional or electrolyte problems (rare in the U.S.)

  • Pregnancy (develops shortly before or after birth)

  • Inherited conditions such as muscular dystrophies

DCM sometimes has different names. For example, alcoholic cardiomyopathy is another name for DCM that occurs from alcohol abuse.

A range of genetic diseases can also cause DCM. These people have what is called familial dilated cardiomyopathy.

For many people with DCM, the cause is unknown. This is called idiopathic dilated cardiomyopathy.

Who is at risk for dilated cardiomyopathy?

If you have a relative with DCM, you may be at higher risk of getting it yourself. If so, you may need to be monitored for the disease. Some things you can do to lower your risk include:

  • Limit how much alcohol you drink

  • Treat high blood pressure

  • Live a healthy lifestyle and stay at a healthy weight

  • Don't use illegal drugs

  • Get prompt treatment for potential causes such as thyroid disease

  • Reduce your risk factors for coronary artery disease

  • Reduce exposure to heavy metals and other toxic causes

What are the symptoms of dilated cardiomyopathy?

In its early stages, DCM may not have any symptoms. Symptoms may get worse gradually or more quickly. Some symptoms include:

  • Shortness of breath with exertion. This may get worse so that you have shortness of breath when at rest.

  • Shortness of breath when lying flat

  • Sudden shortness of breath that wakes you up at night

  • Tiredness (fatigue)

  • Less able to be active and exercise

  • Swelling in the legs and other areas

  • Fainting

  • Weakness or lightheadedness

  • Cough

  • Heart rhythms problems

How is dilated cardiomyopathy diagnosed?

Your healthcare provider will ask you about your health history. This includes any family history of heart disease or sudden death. They will give you a physical exam. You may also have tests, such as:

  • Echocardiogram to look at blood flow in the heart, the size of the heart chambers, and heart motion using ultrasound

  • Electrocardiogram (ECG) to check the heart rhythm

  • Continuous portable ECG monitoring to check heart rhythms away from the healthcare provider’s office

  • Chest X-ray to see the heart anatomy

  • Exercise testing to see how your heart works during exercise

Depending on your health history, you may have other tests, such as:

  • Cardiac stress testing to look for blood flow problems to the heart

  • Blood work to check for various problems or infections such as HIV or Lyme disease

  • Blood work to check for autoimmune diseases

  • Cardiac MRI to further check the heart anatomy and coronary arteries

  • Heart biopsy to look at the heart in more detail

  • Cardiac catheterization with coronary angiography to look at the arteries

  • Genetic testing

How is dilated cardiomyopathy treated?

Treatment of DCM depends on severity and cause. The first step is to treat any underlying causes. For example:

  • Eliminate exposures to toxins, such as alcohol and cocaine

  • Treat diabetes or thyroid disease

  • Treat infectious conditions

  • Fix nutrition problems

In some cases, DCM gets much better after treatment of an underlying cause. In other cases, the damage is permanent. Then the treatment focuses on managing symptoms. Your healthcare provider might prescribe treatments such as:

  • Water pills (diuretics) to reduce swelling

  • Medicines such as beta-blockers to reduce the heart’s workload and make it more efficient

  • Medicines such as ACE inhibitors to help the heart pump better, protect the heart, and slow the progress of the disease

  • Blood thinners (anticoagulants) to prevent blood clots

  • Medicines to help prevent heart rhythm problems

  • Lifestyle changes, such as limiting how much fluids and salt you get, eating a heart-healthy diet, staying away from alcohol and tobacco, and exercising

Your healthcare provider might also advise an implantable cardioverter-defibrillator (ICD). You may need this device if you are at risk for heart rhythms that can cause sudden death. If you also have coronary artery disease or severe valve disease, you may need a procedure or heart surgery. If your condition becomes very severe, you may need a heart transplant in the future.

What are possible complications of dilated cardiomyopathy?

Complications that can occur include:

  • Fluid retention

  • Stroke from a blood clot in the heart that travels to the brain

  • Heart rhythm problems

  • Increased risk for complications during pregnancy

  • Heart valve problems

  • Sudden cardiac death from a dangerous heart rhythm

Can dilated cardiomyopathy be prevented?

Some cases of DCM can be prevented. Not abusing alcohol or illegal drugs may prevent DCM. Quick treatment of other medical causes can also prevent some cases of DCM.

How do I manage dilated cardiomyopathy?

Your healthcare provider may give you other instructions about how to manage your DCM.

  • Your healthcare provider may want to treat you for other heart conditions. This might include medicines for high blood pressure or high cholesterol.

  • Talk with your healthcare provider about what kinds of exercise are OK for you.

  • You might need other lifestyle changes such as losing weight, quitting smoking, or improving your diet. You may need to limit your salt.

  • You may need to reduce how much alcohol or caffeine you have. These increase the risk for heart rhythm problems.

  • Monitor your symptoms carefully. If you are gaining weight quickly, it might be a sign of increased fluid retention because your heart is not working well.

When should I call my healthcare provider?

See a healthcare provider right away if you have severe symptoms such as chest pain or severe shortness of breath. See your provider if you gain a lot of weight. See your provider soon if your symptoms are slowly getting worse.

Key points about dilated cardiomyopathy

  • Dilated cardiomyopathy affects the heart muscle. The heart enlarges and becomes thin. The heart can't pump blood as well.

  • The condition also sometimes leads to dangerous heart rhythm problems and fluid retention.

  • Follow your healthcare provider’s instructions carefully. Take all your medicines as prescribed.

  • See your healthcare provider for regular checkups. This is important even if you don't have any symptoms.

  • Some people with DCM may not need a lot of treatment in the early stages. But some people do need several medicines or procedures.

  • Other family members may need to be checked for DCM, especially if the cause of your disease is unknown.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

  • Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are.

  • Ask if your condition can be treated in other ways.

  • Know why a test or procedure is advised and what the results could mean.

  • Know what to expect if you do not take the medicine or have the test or procedure.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your provider if you have questions.

Online Medical Reviewer: Callie Tayrien RN MSN
Online Medical Reviewer: Stacey Wojcik MBA BSN RN
Online Medical Reviewer: Steven Kang MD
Date Last Reviewed: 4/1/2022
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