What are the three categories of cardiomyopathy, and which is the most common?

• A. Dilated, Hypertrophic, and Restrictive; Dilated is the most common.
• B. Dilated, Hypertrophic, and Arrhythmogenic; Dilated is the most common.
• C. Ischemic, Hypertrophic, and Restrictive; Hypertrophic is the most common.
• D. Dilated, Restrictive, and Unclassified; Dilated is the most common.

Answer: (A)

Three primary forms are used to describe cardiomyopathies: dilated, hypertrophic, and restrictive. Dilated cardiomyopathy is the most common type. It features enlargement of the ventricles with impaired systolic function, leading to heart failure symptoms. Hypertrophic cardiomyopathy involves thickened ventricular walls, often with diastolic dysfunction, while restrictive cardiomyopathy is marked by stiff ventricles causing diastolic dysfunction with relatively preserved systolic function.

Other terms you might see, like ischemic cardiomyopathy, describe myocardial dysfunction due to coronary artery disease rather than a primary cardiomyopathy, and arrhythmogenic cardiomyopathy is a separate entity. But the classic trio taught is dilated, hypertrophic, and restrictive, with dilation being the most common form.