Dilated cardiomyopathy is a disease of the heart muscle that usually starts in your heart's main pumping chamber (left ventricle). The ventricle stretches and thins (dilates) and can't pump blood as well as a healthy heart can. Over time, both ventricles may be affected. The term "cardiomyopathy" refers to diseases that affect the heart muscle itself.

Dilated cardiomyopathy might not cause symptoms, but for some people it can be life-threatening. It's a common cause of heart failure. Dilated cardiomyopathy can also lead to irregular heartbeats (arrhythmias), blood clots or sudden death.

The condition can affect anyone, including infants and children.


Signs and symptoms of dilated cardiomyopathy may include:

  • Fatigue
  • Shortness of breath (dyspnea) when you're active or lying down
  • Reduced ability to exercise
  • Swelling (edema) in your legs, ankles, feet and abdomen
  • Chest pain or feelings of having a fast-beating, fluttering or pounding heart (palpitations)
  • Extra or unusual sounds heard when your heart beats (heart murmurs), which your doctor may find during a physical examination

Some people with dilated cardiomyopathy don't have any signs or symptoms in the early stages of the disease.

When to see a doctor

If you are short of breath or have other symptoms of dilated cardiomyopathy, see your doctor as soon as possible. Call 911 or your local emergency number if you have chest pain that lasts more than a few minutes or have severe difficulty breathing.

If a family member has dilated cardiomyopathy, talk to your doctor. Early detection using genetic testing may benefit people with inherited forms of dilated cardiomyopathy who have no apparent signs or symptoms.


It may be difficult to determine the cause of dilated cardiomyopathy. The condition often runs in families (is inherited). However, many things can cause the left ventricle to dilate and weaken, including:

  • Diabetes
  • Obesity
  • Heart rhythm problems (arrhythmias)
  • High blood pressure (hypertension)
  • Complications of late-stage pregnancy
  • Excessive iron in your heart and other organs (hemochromatosis)
  • Certain infections

Other possible causes of dilated cardiomyopathy include:

  • Alcohol abuse
  • Use of certain cancer medications
  • Use of illegal drugs, such as cocaine or amphetamines
  • Exposure to toxins, such as lead, mercury and cobalt

Risk factors

Risk factors for dilated cardiomyopathy include:

  • Long-term high blood pressure
  • Family history of dilated cardiomyopathy, heart failure or sudden cardiac arrest
  • Inflammation of the heart muscle from immune system disorders, such as lupus
  • Damage to the heart muscle from certain diseases, such as hemochromatosis
  • Neuromuscular disorders, such as muscular dystrophy
  • Long-term excessive alcohol or illegal drug use


Complications from dilated cardiomyopathy include:

  • Heart failure. If you have dilated cardiomyopathy, your heart might not be able to supply your body with the blood it needs to work properly, leading to heart failure. Fluid can build up in the lungs, abdomen, legs, ankles and feet.
  • Heart valve regurgitation. Enlargement of the left ventricle may make it harder for your heart valves to close, causing a backward flow of blood and making your heart pump less effectively.
  • Heart rhythm problems. Changes in your heart's structure and changes in pressure on your heart's chambers can lead to the development of abnormal heart rhythms (arrhythmias).
  • Sudden cardiac arrest. Dilated cardiomyopathy can cause your heart to suddenly stop beating.
  • Blood clots (emboli). Pooling of blood in the left ventricle can lead to blood clots, which may enter the bloodstream and cut off the blood supply to vital organs. These blood clots can cause stroke, heart attack or damage to other organs. Arrhythmias can also cause blood clots.


Dilated cardiomyopathy often runs in families, and is not preventable. However, healthy lifestyle habits can help you prevent or reduce complications of dilated cardiomyopathy. If you have or are at risk for dilated cardiomyopathy:

  • Don't smoke.
  • Don't drink alcohol, or drink in moderation.
  • Don't use cocaine or other illegal drugs.
  • Eat a healthy diet that is low in salt (sodium).
  • Maintain a healthy weight.
  • Follow an exercise program recommended by your doctor.
  • Get enough sleep and rest.
  • Manage stress.

March 31, 2021
  1. Fuster V, et al, eds. Dilated cardiomyopathy: Definition. In: Hurst's The Heart. 14th ed. McGraw-Hill; 2017. https://accessmedicine.mhmedical.com. Accessed Feb. 2, 2021.
  2. Papadakis MA, et al., eds. Dilated cardiomyopathy. In: Current Medical Diagnosis & Treatment 2021. 60th ed. McGraw Hill; 2021. https://accessmedicine.mhmedical.com. Accessed Feb. 2, 2021.
  3. Cardiomyopathy. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/print/4916. Accessed Feb. 2, 2021.
  4. Weigner M, et al. Causes of dilated cardiomyopathy. https://www.uptodate.com/contents/search. Accessed Feb. 2, 2021.
  5. Ferri FF. Cardiomyopathy, dilated. In: Ferri's Clinical Advisor 2021. Elsevier; 2021. https://www.clinicalkey.com. Accessed Feb. 2, 2021.
  6. Mankad R (expert opinion). Mayo Clinic. Feb. 27, 2021.
  7. Sacubitril/valsartan oral. Facts & Comparisons eAnswers. https://www.wolterskluwercdi.com/facts-comparisons-online. Accessed Mar. 1, 2021.