What is cardiomyopathy and how does it appear histologically?

Cardiomyopathy refers to a group of diseases that affect the heart muscle. There are three main types: dilated, hypertrophic, and restrictive. Dilated cardiomyopathy shows myocyte hypertrophy, interstitial fibrosis, and myofibrillar loss. Hypertrophic cardiomyopathy is characterized by myocyte disarray, significant myocyte hypertrophy, and interstitial fibrosis. Restrictive cardiomyopathy shows less specific changes but often includes endomyocardial fibrosis and abnormal deposition of extracellular matrix proteins.