Cardiomyopathy is a weakening of the heart muscle or a change in heart muscle structure. It is often associated with inadequate heart pumping or other heart function problems.

Common types of cardiomyopathy include:

• Dilated cardiomyopathy is a condition in which the heart becomes weakened and enlarged. It cannot pump blood efficiently. Many different medical problems can cause this type of cardiomyopathy.
• Restrictive cardiomyopathy refers to a group of disorders in which the heart chambers are unable to properly fill with blood because of stiffness in the heart.
• Hypertrophic cardiomyopathy (HCM) is a condition in which the heart muscle becomes thick. This thickening makes it harder for blood to leave the heart, forcing the heart to work harder to pump blood. This type of cardiomyopathy is passed down through families.

Common causes of cardiomyopathy are:

• Alcoholism and cocaine use
• Chemotherapy drugs
• Pregnancy
• Genetic defects
• Amyloidosis
• End-stage kidney disease
• Infections due to viruses, HIV, Lyme disease, Chagas disease
• Long-term, severe high blood pressure
• Nutritional deficiencies (such as selenium, thiamine, calcium)
• Systemic lupus erythematosus

Please see the linked articles for details on a specific type of cardiomyopathy:

• Dilated cardiomyopathy
• Hypertrophic cardiomyopathy
• Restrictive cardiomyopathy
• Ischemic cardiomyopathy
• Peripartum cardiomyopathy (occurs during or in the first 5 months after pregnancy)

When the cause of the dilated cardiomyopathy can be identified, efforts are aimed at treating that condition (for example, stopping alcohol or cocaine use). Often, no specific cause can be identified.

Attempts are also made to find a "trigger" that may have caused a patient's symptoms to suddenly get worse. Examples include:

• Not taking medications correctly
• Increasing salt or fluid intake
• Drinking alcohol

The overall treatment of cardiomyopathies is focused on treating heart failure. However, each type of cardiomyopathy may be treated differently.

The outlook depends on many different things, including:

• Severity of the heart problem
• Type of cardiomyopathy
• Cause of the cardiomyopathy
• How well you respond to treatment

The disorder is long-term (chronic) and the condition may get worse very quickly.

Hare JM. The dilated, restrictive, and infiltrative cardiomyopathies. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Libby: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007: chap 64.