Cardiomyopathy is a condition where the heart muscle is abnormal. The main types of cardiomyopathy include dilated, hypertrophic and restrictive cardiomyopathy. Cardiomyopathy refers to diseases of the heart muscle. These diseases have a variety of causes, symptoms, and treatments.In cardiomyopathy, the heart muscle becomes enlarged, thick, or rigid. In rare cases, the muscle tissue in the heart is replaced with scar tissue. As cardiomyopathy worsens, the heart becomes weaker. It's less able to pump blood through the body and maintain a normal electrical rhythm. This can lead to heart failure or arrhythmia. In turn, heart failure can cause fluid to build up in the lungs, ankles, feet, legs, or abdomen.