Source: National Heart, Lung, and Blood Institute
is a disease of the heart muscle. The heart loses its ability to pump blood
and, in some instances, heart rhythm is disturbed, leading to irregular
heartbeats, or arrhythmias. Usually, the exact
cause of the muscle damage is never found.
Cardiomyopathy differs from many other heart disorders in a couple of ways. First, the types not related to coronary atherosclerosis are fairly uncommon. Cardiomyopathy affects about 50,000 Americans. However, the condition is a leading reason for heart transplantation.
Second, unlike many other forms of heart disease that affect middle-aged and older persons, certain types of cardiomopathies can, and often do, occur in the young. The condition tends to be progressive and sometimes worsens fairly quickly.
Dilated cardiomyopathy occurs most often in middle-aged people and more often in men than women. However, the disease has been diagnosed in people of all ages, including children.
In most cases, the disease is idiopathic--a specific cause for the damage is never identified.
But some factors have been linked to the disease's occurrence. For instance, alcohol has a direct suppressant effect on the heart. Dilated cardiomyopathy can be caused by chronic, excessive consumption of alcohol, particularly in combination with dietary deficiencies. Also, dilated cardiomyopathy occasionally occurs as a complication of pregnancy and childbirth. Other factors are: various infections, mostly viral, which lead to an inflammation of the heart muscle (myocarditis); toxins (such as cobalt, once used in beers, for instance); and, rarely, heredity.
Some drugs, used to treat a different medical condition, also can damage the heart and produce dilated cardiomyopathy. Such drugs include doxorubicin and daunorubicin, both used to treat cancer.
Whatever the cause, the clinical and pathological manifestations of dilated cardiomyopathy are usually the same.
Dilated cardiomyopathy can be present for several years with