Cardiomyopathies Flashcards
What is a cardiomyopathy?
Any disease of cardiac muscle; leads to changes in size of heart chambers and heart thickness
What are the classifications of cardiomyopathy?
Dilated
Restrictive
Hypertrophic
What are some of the causes of dilated cardiomyopathy?
genetics
alcohol - common in alcoholics
chemotherapy agents - doxorubicin
Clinical features of dilated cardiomyopathy?
General picture of heart failure; dyspnoea pulmonary oedema fatigue RVF emboli AF VT
What are some of the signs of dilated cardiomyopathy?
raised pulse and JVP
decreased BP
low ejection fraction (low CO)
displaced apex
What is the effect of a hypertrophic heart on contraction?
strong contraction
Hypertrophic myopathy causes dysfunction of systole or diastole?
diastole (not systolic since contraction fine)
diastolic dysfunction - heart cannot relax
what are some of the genes involved in hypertrophic cardiomyopathy?
sarcomere-related genes:
beta-myosin heavy chain
myosin binding protein C
What would you see on biopsy of hypertrophic cardiomyopathy?
disorganised swirls of myofibrils
What is the type of inheritance of hypertrophic obstructive cardiomyopathy?
autosomal dominant
What might an ECG of hypertrophic cardiomyopathy show?
LVH progressive T wave inversion deep Q waves (inferior & lateral leads) AF WPW syndrome ventricular ectopics VT
What would an ECHO show of hypertrophic cardiomyopathy?
asymmetrical septal hypertrophy
small LV cavity with hyper-contractile posterior wall
What medication would you give for symptomatic benefit of hypertrophic cardiomyopathy?
b-blocker or verapamil - aim is to reduce ventricular contractility
Which anti-arrhythmic drug might a person with a hypertrophic cardiomyopathy need, and why?
diastolic dysfunction - so heart can’t relax…therefore need something to either slow HR or increase time between APs…
Type 3 are rhythm control of atria or ventricles
So, give amiodarone to increase AP duration and effective refractory period
What would you have to consider when giving amiodarone as an anti-arryhthmic?
age of patient - amiodarone has adverse effects when used in the long run
if used along with a beta-blocker or verapamil then there is increased risk of bradycardia
Why would you give a person with hypertrophic cardiomyopathy an anti-coagulant?
for paroxysmal AF or systemic emboli
What are main features of restrictive cardiomyopathy?
lack of compliance stiff heart diastolic dysfunction (doesn't fill well) can look normal bi-atrial dilatation
What causes atrial dilatation in restrictive cardiomyopathy?
back pressure from stiff ventricles
What are the main causes of restrictive cardiomyopathy?
deposition of something in the myocardium: amyloidosis sarcoidosis haemochromatosis tumours fibrosis
How would a restrictive cardiomyopathy present?
feature of RVF raised JVP hepatomegaly oedema ascites
What is the sign for amyloidosis on biopsy?
stains positive for ‘congo red’
waxy pink material
exhibits apple green bienfringence
What would an ECG of restrictive cardiomyopathy look like?
low voltage conduction abnormalities, e.g. AV block or SA node dysfunction
Which cardiomyopathy involves largely the replacement of the right ventricle with fatty material?
Arrythmogenic Right Ventricular dysplasia
What does penetrance of genetic disease mean?
penetrance describes the proportion of individuals with a disease-causing mutation who exhibit clinical symptoms
Why is arrhythmogenic right ventricular dysplasia difficult to diagnose?
the RV normally looks quite fatty
range of non-specific symptoms (syncope & palpitations during exercise)
sudden death can be first time it presents
What is myocarditis?
inflammation of the myocardium
What are the common viral causes of myocarditis?
Coxsackie A and B HIV Enterovirus Hepatitis Mumps
Which autoimmune conditions are associated with myocarditis?
SLE
scleroderma
sarcoid
heart transplant rejection
What would the myocardium look like in infectious myocarditis?
thickened and ‘beefy’
Which type of hypersensitivity reaction is non-infectious myocarditis?
type IV
Hypersensitivity to drugs causes which type of myocarditis?
eosinophilic myocarditis
Hypersensitivity to infection causes ?
rheumatic fever after strep sore throat
Which gram positive group of organisms causes the classical sore throat?
streptococcus - Group A Strep
What changes occur to the heart in rheumatic fever?
patchy inflammation of myocardium
short, thick chordae tendinae
mitral stenosis with thickening & fusion of valve leaflets