Cardiomyopathies are diseases of the heart muscle, also known as the myocardium, in which the actual muscle cells and surrounding tissues are sick.

Cardiomyopathies can be primary, meaning the sickness mainly involves the heart.

They can also be secondary, meaning the sickness is a result of another disease or toxin and may also affect many organ systems within the body, including the heart.

Patients with cardiomyopathy will most commonly have a heart that looks normal but does not work well.