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What is cardiomyopathy?

Any disorder that affects the heart muscle is called a cardiomyopathy.  Cardiomyopathy causes the heart to lose its ability to pump blood well. In some cases, the heart rhythm also becomes disturbed. This leads to arrhythmias (irregular heartbeats). There are many causes of cardiomyopathy, including:

  • Alcohol abuse

  • High blood pressure

  • Coronary artery disease

  • Viral infections 

  • Certain medicines


How does cardiomyopathy differ from other heart disorders?

Cardiomyopathy differs from many of the other disorders of the heart in several ways, including:

  • Cardiomyopathy can occur in young people.

  • The condition tends to be progressive. Sometimes it worsens fairly quickly.


  • Dilated cardiomyopathy is a leading cause for a heart transplant.

  • It is often the result of gradual changes of heart structure over time

What causes cardiomyopathy?

Viral infections in the heart are a major cause of cardiomyopathy. In some cases, another disease or its treatment causes cardiomyopathy. This might include complex congenital (present at birth) heart disease, nutritional deficiencies, uncontrollable, fast heart rhythms, or certain types of chemotherapy for cancer. Sometimes, cardiomyopathy can be linked to a genetic defect. Other times, the cause is unknown. Three types of cardiomyopathy typically affect adults. They are:

  • Hypertrophic cardiomyopathy

  • Dilated cardiomyopathy

  • Restrictive cardiomyopathy

What is hypertrophic cardiomyopathy?

Hypertrophic cardiomyopathy occurs when the muscle of the left ventricle thickens. This can block blood flow to the rest of the body. Hypertrophic cardiomyopathy can affect the heart's mitral valve, causing blood to leak backward through the valve.


  • It can affect men and women of all ages. Symptoms can appear in childhood or adulthood.

  • Symptoms include shortness of breath on exertion, dizziness, fainting, and chest pain (angina).

  • Some people have arrhythmias, which may lead to sudden death.

What is dilated cardiomyopathy?

Dilated cardiomyopathy is the most frequent form of cardiomyopathy. The cavity of the heart is enlarged and stretched, compromising the heart's ability to pump normally and relax appropriately:

  • This occurs most often in adults ages 20 to 60. It is more common in men than women, but has been diagnosed in people of all ages, including children.

  • Most people eventually develop heart failure.

  • Dilated cardiomyopathy can be caused by chronic, heavy alcohol use and nutritional deficiencies tied to alcoholism.

  • It sometimes occurs as a complication of pregnancy and childbirth.

  • Other possible causes include: alcohol abuse, infections, and illicit drugs. Rarely, it is inherited. Sometimes medicines used to treat a different medical condition can damage the heart and cause dilated cardiomyopathy. However, in most cases, a specific cause is never found.

What is restrictive cardiomyopathy?

Restrictive cardiomyopathy occurs when the heart muscle becomes stiff and not able to fill with blood properly. It's the least common type of cardiomyopathy in the U.S.

  • It often occurs due to an underlying problem, such as amyloidosis, hemochromatosis, scleroderma, or sarcoidosis.


  • Symptoms may include fatigue, swelling of the arms and legs, and trouble breathing on exertion.

What is arrhythmogenic right ventricular dysplasia?

ARVD is a rare type of cardiomyopathy that occurs if the muscle tissue in the right ventricle dies and is replaced by fat or scar tissue:

  • This process disrupts the heart's electrical system, causing arrhythmias.  

  • It usually affects teens and young adults.  

  • Symptoms include heart palpitations and fainting after physical activity. 

  • It can cause sudden cardiac arrest in young athletes.                

  • It may require implantation of a device to prevent death from an arrhythmia

Online Medical Reviewer: Fetterman, Anne, RN, BSN
Online Medical Reviewer: Gandelman, Glenn, MD, MPH
Date Last Reviewed: 11/1/2016
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