Cardiomyopathy is an ongoing disease process that damages the muscle wall of the lower chambers of the heart. About 50,000 Americans develop cardiomyopathy each year. Congestive cardiomyopathy is the most common form of cardiomyopathy. In congestive cardiomyopathy, also called dilated cardiomyopathy, the walls of the heart chambers stretch (dilate) to hold a greater volume of blood than normal. Another form of cardiomyopathy, hypertrophic cardiomyopathy, causes the walls of the heart's chambers to thicken abnormally.

Congestive cardiomyopathy is the final stage of many heart diseases and the most common condition resulting in congestive heart failure. It may be caused by a number of conditions, including coronary artery disease, infections, noninfectious inflammatory conditions, alcohol and other drugs or toxins, hypertension, nutritional and metabolic disorders, and pregnancy.

Infections caused by bacteria, viruses, and other microorganisms can involve the heart, causing inflammation of the heart muscle (myocarditis). The inflammation may damage the heart...