[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Heart](https://durgical.com/en/general-pathology/areas/heart/) › Cardiomyopathies: classification

# Cardiomyopathies: classification

- Topic

Cardiomyopathies are diseases of the heart muscle itself. They are grouped by shape and function: dilated, thick, stiff or arrhythmia-prone.

Updated Nov 12, 2026

## Key points

- Dilated: about 90 % of cardiomyopathies; impaired contraction; causes include genes (TTN), alcohol, myocarditis, pregnancy, drugs.
- Hypertrophic: sarcomere mutations (MYH7, MYBPC3), autosomal dominant; diastolic dysfunction, outflow obstruction, sudden death.
- Restrictive: stiff ventricles; amyloidosis, sarcoidosis, radiation, iron, endomyocardial fibrosis.
- Arrhythmogenic: desmosome gene mutations; right ventricle mainly; sudden death in young people.
- Shared ends: heart failure, arrhythmias, thromboembolism, sudden death.

## 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](https://durgical.com/en/conditions/dilated-cardiomyopathy/) | Dilated, all chambers, normal or thin wall | Systolic failure (low ejection fraction) | Genetic (TTN, LMNA, dystrophin), alcohol, myocarditis, peripartum, anthracyclines |
| [Hypertrophic cardiomyopathy](https://durgical.com/en/conditions/hypertrophic-cardiomyopathy/) | Thick wall (often asymmetric septum), small cavity | Diastolic failure, outflow obstruction | Sarcomere gene mutations (MYH7, MYBPC3) |
| [Restrictive cardiomyopathy](https://durgical.com/en/conditions/restrictive-cardiomyopathy/) | Normal size, stiff; big atria | Restricted filling | Amyloid, sarcoid, iron, radiation, endomyocardial fibrosis |
| [Arrhythmogenic cardiomyopathy](https://durgical.com/en/conditions/arrhythmogenic-right-ventricular-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.

## Memory aid

Baggy (dilated), beefy (hypertrophic), board-stiff (restrictive) or burned-out and fatty on the right (arrhythmogenic).

## 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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## Elsewhere in DurgiPedia

- [The ventricular pressure–volume loop](https://durgical.com/en/physiology/the-ventricular-pressure-volume-loop/)
- [Cardiac muscle: intercalated discs](https://durgical.com/en/histology/cardiac-muscle-intercalated-discs/)

## Connections

## Related 6

- [Dilated cardiomyopathy](https://durgical.com/en/general-pathology/dilated-cardiomyopathy/)
- [Hypertrophic cardiomyopathy](https://durgical.com/en/general-pathology/hypertrophic-cardiomyopathy/)
- [Restrictive cardiomyopathy and cardiac amyloidosis](https://durgical.com/en/general-pathology/restrictive-cardiomyopathy-and-cardiac-amyloidosis/)
- [Arrhythmogenic cardiomyopathy](https://durgical.com/en/general-pathology/arrhythmogenic-cardiomyopathy/)
- [Myocarditis](https://durgical.com/en/general-pathology/myocarditis/)
- [Mendelian inheritance: autosomal dominant, recessive and X-linked](https://durgical.com/en/general-pathology/mendelian-inheritance-autosomal-dominant-recessive-and-x-linked/)

## Related conditions 7

- [Dilated cardiomyopathy](https://durgical.com/en/conditions/dilated-cardiomyopathy/)
- [Hypertrophic cardiomyopathy](https://durgical.com/en/conditions/hypertrophic-cardiomyopathy/)
- [Restrictive cardiomyopathy (amyloid, sarcoid, haemochromatosis)](https://durgical.com/en/conditions/restrictive-cardiomyopathy/)
- [Arrhythmogenic right ventricular cardiomyopathy](https://durgical.com/en/conditions/arrhythmogenic-right-ventricular-cardiomyopathy/)
- [Peripartum cardiomyopathy](https://durgical.com/en/conditions/peripartum-cardiomyopathy/)
- [Takotsubo (stress) cardiomyopathy](https://durgical.com/en/conditions/takotsubo-cardiomyopathy/)
- [Chagas cardiomyopathy](https://durgical.com/en/conditions/chagas-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](https://medlineplus.gov/cardiomyopathy.html) (MedlinePlus, US National Library of Medicine, 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/cardiomyopathies-classification/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/cardiomyopathies-classification/