Cardiovascular System >
Cardiomyopathy
“A general term for diseases of the heart muscle, where the walls of the heart chambers have become thickened, stiff, or stretched.”
- Forms of Cardiomyopathy:
- Hypertrophic Cardiomyopathy (HC)
- Restrictive Cardiomyopathy (RC)
- Dilated Cardiomyopathy (DC)
- Broken Heart Syndrome (Takotsubo Cardiomyopathy, TC)
Risk Factors
- Uncontrolled high blood pressure
- Alcohol and recreational drugs
- Heart valve problem
- Diseases of the tissues or blood vessels (sarcoidosis, amyloidosis, lupus, polyarteritis nodosa, vasculitis or muscular dystrophy)
Aetiology
- HC – Autosomal Dominant Genetic Mutation in one of the 12 genes that are important for heart development
- RC – Usually autosomal dominant inheritance, but autosomal recessive, X-linked and mitochondrial-transmitted disease occurs
- DC – 50% Familial Dilated Cardiomyopathy (FDCM) – Autosomal Dominant, 50% varied inheritance
- TC – Not inherited. Excess of the stress hormone adrenaline caused by emotional or physical distress (e.g. bereavement, domestic abuse, physical assault or recent surgery)
Pathophysiology
- HC:
- Mutation in the sarcomere
- Instigates a series of proximal defects (e.g. altered ATPase activity)
- Molecular changes induce histological and morphological changes
- Myocyte hypertrophy and fibrosis
- Reduced ventricular volume
- RC:
- Cardiomyocytes replaced with abnormal scar tissue
- ventricular stiffness
- Contraction unaffected however filling is ↓
- ↓ CO
- Reduced ventricular filling causes atria dilation
- DC:
- Primary cardiomyopathic process
- ↓ Systolic function caused by myocardial remodelling
- ↑ End-systolic / end-diastolic volumes
- Progressive dilatation
- Significant tricuspid and mitral valve insufficiency
- Further lowers the ejection fraction
- TC – Precise cause is unknown:
- Likely, surging stress hormones (esp. adrenaline) “stun” the heart
- Triggering changes in cardiomyocytes and coronary blood vessels
- Prevent effective LV contraction.
- REVERSIBLE
Clinical Presentation
- HC – Dizziness, Chest pain, SOB, & Syncope
- The most common cause of sudden unexpected death in childhood and in young athletes
- RC – Similar to HF – SOB, Oedema, Fatigue, Rhythm problems
- DC – Similar to HF – SOB, Oedema, Fatigue, Palpitations
- TC – Similar to a heart attack – Chest pain, SOB, N&V
Investigations
- Bloods: n/a
- Imaging:
- MRI
- Echocardiogram
- Special:
- ECG
- 24 or 48-hour ECG monitor
- Exercise test
- A detailed family tree may be required for the diagnosis of a familial cardiomyopathy
Management
- There’s usually no cure for cardiomyopathy, but the treatments can be effective at controlling symptoms and preventing complications
- Most commonly used medications are: ACE inhibitors, angiotensin receptor blockers, beta-blockers and warfarin
Complications
- Heart failure
- Heart valve regurgitation
- Sudden cardiac arrest