cardiomyopathy

Think of the heart as a muscular pump made mostly of one specialised muscle. Cardiomyopathy is the family of diseases in which that muscle itself goes wrong — it becomes too stretched and floppy, too thick and stiff, or too rigid to relax — so the pump no longer fills and empties the way it should. The plumbing (arteries) and the valves may be fine; the problem lives in the muscle wall.

Doctors group cardiomyopathies by how the muscle changes: dilated (enlarged, weakly squeezing chambers), hypertrophic (abnormally thickened walls), restrictive (stiff walls that resist filling), and arrhythmogenic (muscle replaced by fat and scar). Causes range from inherited gene mutations and viral infection to long-standing high blood pressure, toxins such as alcohol, and pregnancy. Many cases lead to heart failure or dangerous rhythm disturbances.

An important honest caveat: the term is used both narrowly and broadly. Classically, cardiomyopathy referred to muscle disease not caused by coronary artery disease, valve disease, or hypertension. In everyday clinical language, however, weakened muscle from chronic coronary disease is often called ischemic cardiomyopathy, so the boundaries are not absolute. The label tells you the muscle is sick; finding the cause takes further testing.