Educational scope notice: This is a study note for medical students, not medical advice, diagnosis, or treatment guidance. Clinical management should follow local protocols and current guidelines.
Cardiomyopathy means disease of the myocardium — the heart muscle itself. Ventricular size, function, or structure changes because the muscle is diseased, not because the coronary arteries are blocked, blood pressure is high, a valve is faulty, or the heart formed abnormally. That distinction — primary muscle disease versus muscle suffering from something outside itself — is the starting point for the rest of this cluster.
When a cardiomyopathy is first suspected, current European guidance positions cardiac magnetic resonance (CMR) early in the workup: the 2023 ESC cardiomyopathies guideline gives CMR a Class I recommendation with Level of Evidence B at first suspicion. The teaching material dates the practical change behind this to roughly 2006. Before tissue-level imaging, unexplained dysfunction often stopped at coronary angiography — normal coronaries ended the search at heart disease without coronary involvement. CMR added a way to distinguish fibrosis from infiltration from storage, and repeated imaging now also tracks disease over time.
The family at a glance
Tradition groups cardiomyopathies by what the ventricle looks like. The shape is a useful starting description, but it is not the whole diagnosis: the same genetic disease can wear different shapes, and infiltrative or storage diseases can move between shapes as they advance.
| Phenotype | Ventricular picture | Place in this cluster |
|---|---|---|
| Hypertrophic | Increased wall thickness, normal or small cavity | Taught directly: hypertrophic cardiomyopathy, and the hypertrophic appearance of early amyloidosis and early Fabry disease |
| Dilated | Enlarged cavity, thin walls, reduced systolic function | Named for orientation; no dedicated note in this cluster |
| Restrictive | Normal cavity, stiff walls, severe diastolic limitation | Met as late-stage physiology in amyloidosis; no standalone note here |
| Arrhythmogenic | Arrhythmia-predominant disease with fibrofatty replacement | Named for orientation; no dedicated note in this cluster |
Choose a route through the cluster
- Cardiomyopathies and cardiac MRI: the imaging gateway. It teaches what each sequence measures and how the combined tissue pattern narrows the differential. Read this first if the scans feel opaque.
- Cardiac amyloidosis: the infiltrative model. It teaches the three cardiac types, the diffuse tissue signature, and the stepwise pathway that usually types amyloid without biopsy.
- Fabry disease: the storage model. It teaches X-linked enzyme deficiency, its distinctive imaging signature, and why early diagnosis plus family screening change outcomes.
- Hypertrophic cardiomyopathy: the sarcomere model. It teaches asymmetric hypertrophy, dynamic obstruction, the athletic-heart distinction, and how fibrosis and risk factors guide defibrillator decisions.
A useful sequence is imaging first, then the three diseases. The scan patterns give each disease something visible to hold on to.
A diagnostic way of thinking
When ventricular dysfunction has no explained cause, the teaching approach runs through five questions:
- Coronary or not? Dysfunction and enhancement confined to a coronary territory point toward ischaemia; diffuse disease with a non-coronary pattern points toward the muscle itself.
- What does the tissue say? T1, T2, extracellular volume, and the enhancement pattern narrow the differential before any invasive step.
- Active or established? Oedema marks an active process; enhancement without oedema marks established scar or deposit.
- Is there a treatable cause? Fabry disease, light-chain amyloidosis, transthyretin amyloidosis, and obstructive hypertrophic cardiomyopathy each carry specific therapy, so finding them matters.
- Does age rule anything out? No. Advanced age alone should not deny the workup: diffuse disease can hide behind a mild echocardiogram at any age, and a diagnosis can matter for the family as well.
Evidence anchors
- Arbelo E, et al. 2023 ESC Guidelines for the management of cardiomyopathies: https://doi.org/10.1093/eurheartj/ehad194
- Maron BJ, et al. Contemporary definitions and classification of the cardiomyopathies: https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.106.174287