Cardiomyopathy Flashcards
Define cardiomyopathy
Group of heart muscle (myocardium) diseases that are associated with mechanical and/or electrical dysfunction
Dilated (most common), restrictive or hypertrophic
Aetiology of Dilated cardiomyopathy
Alcohol
Drugs e.g. doxorubicin, cocaine
Viruses e.g. coxsackie B -> myocarditis
Familial (25%)
Thyrotoxicosis
Haemochromatosis
Symptoms and signs of dilated cardiomyopathy
Heart failure symptoms
Thromobembolism
FMHx sudden death
Heart failure signs
Displaced apex beat
Mitral and tricuspid regurgitation
S3
Arrhythmia
Aetiology of restrictive cardiomyopathy
Sarcoidosis, amyloidosis
Haemochromatosis
Scleroderma
Loeffler’s endocarditis
Post-radiotherapy
Symptoms and signs of restrictive cardiomyopathy
Dyspnoea
Fatigue
Arrhythmias
Ankle/abdominal swelling
Heart failure signs
Kussmaul’s sign
S3
Palpable apex beat
Ascites/ ankle oedema / hepatomegaly
Aetiology of hypertrophic cardiomyopathy
Primary
Inherited - autosomal dominant (50%)
Mutation in myosin, troponin T → hypertrophy, especially of septum and ventricle → stiffer muscle which affects pumping and disruption of electrical conduction
Secondary
Infective (Coxsackie B virus, Chagas disease)
Infiltrative (Amyloidosis)
Storage (Haemochromatosis)
Toxicity (Doxorubicin, Alcoholic cardiomyopathy)
Inflammatory (Sarcoidosis)
Endocrine (Diabetes mellitus, Thyrotoxicosis, Acromegaly)
Neuromuscular (Friedreich’s ataxia, Duchenne-Becker muscular dystrophy, Myotonic dystrophy)
Nutritional deficiencies (Beriberi (thiamine))
Autoimmune (SLE)
Symptoms and signs of hypertrophic cardiomyopathy
Aortic stenosis: syncope, angina
Sudden cardiac death (FMHx)
Jerky carotid pulse
Double apex (NOT displaced)
Aortic stenosis: ESM, pulsus bisferiens, S4
Investigations for cardiomyopathy
Dilated: Echo - dilation of ventricles + atria + hypokinesia
Restrictive: Gold standard is cardiac MRI
- Echo: non-dilated non-hypertrophied ventricles with atrial enlargement, preserved function and diastolic dysfunction, granular or ‘sparkling’ appearance of myocardium (amyloidosis)
Hypertrophic: Echo - shows asymmetrical septal hypertrophy, obstruction in HOCM, systolic anterior motion (SAM) of the anterior mitral valve
ECG: non-specific ST changes, conduction defects, arrhythmias
- Restrictive: low voltage complex
- Hypertrophic: LAD, LVH signs
CXR: cardiomegaly, signs of heart failure
Endomyocardial biopsy: ?amyloidosis, sarcoidosis
Cardiac catheterisation
Describe Takotsubo cardiomyopathy
‘Stress’-induced cardiomyopathy e.g. patient just found out family member dies then develops chest pain and features of heart failure
Transient, apical ballooning of the myocardium
Treatment is supportive
Aetiology of HOCM
AD, 1 in 500
Defects in the genes encoding contractile protein (mutation in gene encoding β-myosin heavy chain protein or myosin-binding protein C → diastolic dysfunction → LVH → decreased compliance → decreased CO)
Associations: WPW, Friedrich’s ataxia
Biopsy = myofibrillar hypertrophy with chaotic and disorganized fashion myocytes (‘disarray’) and fibrosis
Signs and symptoms of HOCM
Asymptomatic
Sudden death (most commonly due to ventricular arrhythmias / VF), arrhythmias, heart failure
Exertional: dyspnoea, angina, syncope (from hypertrophy of ventricular septum → functional aortic stenosis)
Examination: jerky pulse, large ‘a’ waves, double apex beat, ESM (increases with Valsalva manoeuvre and decreases on squatting, PSM of mitral regurgitation from impaired mitral valve closure)
Investigations for HOCM
Echo (MR SAM ASH)::
- Mitral regurgitation (MR)
- Systolic anterior motion (SAM) of the anterior mitral valve leaflet
- Asymmetric hypertrophy (ASH)
ECG:
- LVH
- Non-specific ST segment and T-wave abnormalities, progressive T wave inversion may be seen
- Deep Q waves
- AF (occasionally)
Management for HOCM
Amiodarone
Beta-blockers / verapamil for symptoms
Cardioverter defibrillator
Dual chamber pacemaker
Endocarditis prophylaxis
Which drugs should be avoided in HOCM
nitrates
ACEi
inotropes
