Cardiomyopathies: classification
- Topic
Cardiomyopathies are diseases of the heart muscle itself. They are grouped by shape and function: dilated, thick, stiff or arrhythmia-prone.
What it is
Cardiomyopathies are heart muscle diseases not explained by coronary disease, hypertension, valve disease or congenital defects. Many are genetic; others are acquired (toxins, infections, pregnancy, infiltration). They are classified by their dominant pattern: dilated cardiomyopathy (systolic failure), hypertrophic cardiomyopathy (thick, hypercontractile but stiff), restrictive cardiomyopathy (stiff, poorly filling) and arrhythmogenic cardiomyopathy (fibrofatty replacement and ventricular arrhythmias).
The four cardiomyopathy patterns
| Type | Ventricle | Function | Main causes |
|---|---|---|---|
| Dilated cardiomyopathy | Dilated, all chambers, normal or thin wall | Systolic failure (low ejection fraction) | Genetic (TTN, LMNA, dystrophin), alcohol, myocarditis, peripartum, anthracyclines |
| Hypertrophic cardiomyopathy | Thick wall (often asymmetric septum), small cavity | Diastolic failure, outflow obstruction | Sarcomere gene mutations (MYH7, MYBPC3) |
| Restrictive cardiomyopathy | Normal size, stiff; big atria | Restricted filling | Amyloid, sarcoid, iron, radiation, endomyocardial fibrosis |
| Arrhythmogenic cardiomyopathy | Right ventricle thinned and dilated, fibrofatty | Ventricular arrhythmias, RV failure | Desmosome mutations (PKP2, DSP, JUP) |
Clinical notes
- Endomyocardial biopsy helps in suspected myocarditis, amyloidosis and other infiltrative diseases; genetic testing guides family screening.
Test yourself
Think of the answer, then tap the question to see it.
Which is the most common cardiomyopathy?
Dilated cardiomyopathy.
What kind of genes are mutated in hypertrophic cardiomyopathy?
Genes encoding sarcomere proteins, most often β-myosin heavy chain (MYH7) and myosin-binding protein C (MYBPC3).
Which cardiomyopathy is caused by desmosome gene mutations?
Arrhythmogenic (right ventricular) cardiomyopathy.
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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Cardiomyopathy | Enlarged Heart | MedlinePlus (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.