5. Cardiomyopathies Flashcards
What does cardiomyopathy refer to?
Primary heart muscle disease - often genetic
Name 3 cardiomyopathies.
- Hypertrophic cardiomyopathy (HCM)
- Dilated cardiomyopathy (DCM)
- Arrhythmogenic right/left ventricular cardiomyopathy (ARVC/ALVC)
What is the usual inheritance pattern for cardiomyopathies?
Autosomal dominant; off-spring have a 50% chance of being affected.
What investigations might you carry out in cardiomyopathy?
CXR, ECG, echo.
Cardiac MR
Describe the pathophysiology of HCM.
Systole is normal but diastole is affected - diastolic heart failure
I.E. strong contractions but relaxation = issue!!
The heart is unable to relax properly due to thickening of the ventricular walls.
At cellular level -> myofibrillar disarray
Give 3 symptoms of HCM.
- Angina.
- Dyspnoea.
- Syncope.
- Palpitations.
What can cause HCM?
Sarcomeric gene mutations e.g. beta myosin, troponin T mutations. About 1 in 500 people are affected.
For HCM, what are the chances of it being caused by genetics and other factors?
50% = autosomal dominant
50% = sporadic
What is the major consequence of HCM?
Sudden cardiac death in young people
What might an ECG look like from a person with HCM?
- Large QRS complexes.
- Large inverted T waves.
Treatment of HCM
Beta blockers/CCBs to control symptoms.
Anticoagulate to prevent embolism.
Implantable defibrillator
Describe the pathophysiology of DCM.
Ventricular dilation and dysfunction = poor contractility
I.E. poor contractions + thin walls
What can cause DCM?
Cytoskeletal gene mutations
Give 3 causes of DCM.
Alcohol, hypertension, haemachromatosis, viral infection, autoimmune, congenital.
Give 3 symptoms of DCM.
DCM usually presents with symptoms similar to those seen in heart failure:
- Breathlessness.
- Tiredness.
- Oedema.
Give 3 clinical features of DCM.
Dyspnoea, embolism or arrhythmia, displaced apex beat, S3 gallop, pleural effusion, oedema, jaundice, ascites.
Treatment of DCM
Bed rest.
Diuretics, digoxin, ACE inhibitors.
Biventricular pacing/implantable cardiac defibrillator
Heart transplant.
What can cause ARVC/ALVC?
Desmosome gene mutations.
Describe the pathophysiology of ARVC/ALVC.
Desmosomes attach cells via their intermediate filaments.
Desmosome mutations lead to myocytes being pulled apart -> muscle undergo programmed cell death.
Ventricles are replaced with fatty, fibrous tissue.
Gap junctions are affected too.
Give a sign of ARVC/ALVC.
Ventricular tachycardia.
What might an ECG look like from a person with ARVC/ALVC.
Epsilon waves.
What is restrictive cardiomyopathy (RCM)?
Rigid myocardium -> poor dilation of the heart -> restricting diastolic ventricular filling
Give 2 causes of RCM.
Amyloidosis. haemachromatosis. sarcoidosis. scleroderma. idiopathic.
What is the commonest cause of restrictive cardiomyopathy?
Amyloidosis (extra-cellular deposition of an insoluble fibrillar protein - amyloid).
Give 3 clinical features / symptoms of RCM.
Raised JVP. oedema, ascites, features of RVH.
Investigations for RCM diagnosis.
Cardiac catheterisation.
