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.
• Hypertrophic cardiomyopathy (HCM) is a condition in which the heart muscle becomes thick. This thickening makes it harder for blood to leave the heart. This type of cardiomyopathy is usually passed down through families.
• Restrictive cardiomyopathy refers to a group of disorders in which the heart chambers are unable to properly fill with blood because of increased stiffness in the heart.

Common causes of cardiomyopathy are:

• Alcoholism and cocaine use
• Amyloidosis
• Chemotherapydrugs
• Coronary artery disease
• End-stage kidney disease
• Genetic defects
• High blood pressure (hypertension)
• Infections due to viruses, HIV, Lyme disease, Chagas disease
• Nutritional deficiencies (such as selenium, thiamine, calcium)
• Pregnancy
• 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 dilated cardiomyopathy can be identified, efforts are aimed at treating that condition (for example, treating high blood pressure or coronary artery disease, or stopping alcohol or cocaine use). Sometimes, 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:

• Drinking alcohol
• Increasing salt or fluid intake
• Not taking medications correctly
• Using recreational drugs, especially stimulants such as cocaine

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:

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

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. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007:chap 64.

Bernstein D. Diseases of the myocardium. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 439.

Wexler RK, Elton T, Pleister A, Feldman D. Cardiomyopathy: An overview. Am Fam Physician. 2009;79:778-784.