Cardiomyopathy 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, it is fairly uncommon, affecting 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-age and older persons, cardiomyopathy can, and often does, occur in the young. The condition tends to be progressive and sometimes worsens fairly quickly.