What is Cardiomyopathy?

by Lance J. Brown

(forwarded by Kim Sweeney)

Cardiomyopathy is a serious disease in which the heart muscle becomes inflamed and does not work as well as it should. There may be multiple causes including viral infections.

Cardiomyopathy can be classified as primary or secondary. Primary cardiomyopathy cannot be attributed to a specific cause, such as hypertension, heart valve disease, artery diseases or congenital heart defects. Secondary cardiomyopathy is due to specific causes and is often associated with diseases involving other organs as well as the heart.

There are three principal types of cardiomyopathy:

• What is hypertrophic cardiomyopathy?
  In this condition, the muscle mass of the left ventricle is larger than normal. In one form of the disease, the wall between the two ventricles (septum) becomes enlarged and obstructs the blood flow from the left ventricle. The syndrome is known as hypertrophic obstructive cardiomyopathy (H.O.C.M.) or asymmetric septal hypertrophy - (A.S.H.). It is also termed idiopathic hypertrophic subaortic stenosis - I.H.S.S.

  Besides obstructing blood flow, the thickened wall sometimes distorts one leaflet of the mitral valve, causing it to become leaky. In over half the cases, the disease is hereditary. Close blood relatives (parents, children or siblings) of such persons often have an enlarged septum, although they may have no symptoms. This disease is most common in young adults. In the other form of the disease, non-obstructive hypertrophic cardiomyopathy, the enlarged muscle does not obstruct blood flow.

  The symptoms of hypertrophic cardiomyopathy include shortness of breath on exertion, dizziness, fainting and angina pectoris (chest pain). Some patients experience cardiac arrhythmias. These abnormal heart rhythms in some cases can lead to sudden death. The obstruction to blood flow from the left ventricle increases the work the ventricle must do, and a heart murmur may be heard.

  A drug known as a beta-blocker (such as propranolol) or a calcium channel blocker is the usual treatment. If a person has an arrhythmia, an antiarrhythmic drug may also be used. Surgical treatment of the obstructive form is possible in some cases if the drug treatment fails.

  What is dilated (congestive) cardiomyopathy?

  This is the most frequent form. The cavity of the heart is enlarged and stretched (cardiac dilation) in contrast to the thickening of the walls in the hypertrophic form. The heart is weak and does not pump normally, and most patients develop congestive heart failure.

  What is restrictive cardiomyopathy?

  This is the least common type in the United States. The myocardium of the ventricles becomes excessively "rigid," and the filling of the ventricles with blood between heart beats is impaired. A person with this type of cardiomyopathy often complains of being tired, may have swelling of the extremities, and may have difficulty breathing on exertion. This type is usually due to another disease process.

Copyright © 1998 American Heart Association
Lance J. Brown "Brownie"