Definition
A cardiomyopathy is a disease in which the heart muscle is structurally and functionally abnormal without coronary artery disease, hypertension, valve disease or congenital heart disease severe enough to explain the abnormality (ESC 2023).
- Many are genetic (mostly autosomal dominant), so screening the family is part of the work-up; others are acquired (alcohol, drugs, myocarditis, infiltration, pregnancy).
- A leading cause of heart failure, of sudden cardiac death (SCD) in the young and of heart transplantation.
Classification (ESC 2023)
Named by the phenotype of the left and right ventricles (LV, RV) at presentation, then by cause (genetic or acquired).
- LV non-compaction is now a trait (hypertrabeculation), not a cardiomyopathy. Takotsubo and peripartum forms are at the end.
Image: “Major categories of cardiomyopathy” by Npatchett, CC BY-SA 4.0, via Wikimedia Commons.
Work-up common to all
- History and a three-generation family tree (SCD, heart failure, transplant, pacemaker at a young age); ECG and 24–48 h Holter.
- Echocardiography first; cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) shows the pattern of scar, fat, oedema or amyloid.
- Natriuretic peptides, troponin, creatine kinase, thyroid function, iron studies; exclude coronary disease when relevant; endomyocardial biopsy only if it changes treatment.
- Genetic testing of the patient, then cascade testing of first-degree relatives; if no variant is found, relatives are screened with ECG and echo.
- Red flags for a specific cause: low QRS voltage with thick walls (amyloidosis), atrioventricular (AV) block when young (LMNA, sarcoidosis), skeletal myopathy, angiokeratoma with proteinuria (Fabry).