Cardiomyopathies Flashcards
Hypertrophic, dilated and restrictive (20 cards)
What is meant by the term ‘cardiomyopathy’?
heart muscle disease
What is the name of heart muscle?
myocardium
What is secondary cardiomyopathy?
this is cardiomyopathy that has happened as a consequence of another disease e.g., hypertension or valve disease
What is meant by ‘hypertrophic’ cardiomyopathy?
this means the muscular walls of the heart get thick, heavy and hypercontractile
What would you see under a microscope in hypertrophic cardiomyopathy?
new sarcomeres, added in parallel
myocyte disarray
Describe the pattern of muscle growth in hypertrophic cardiomyopathy
usually asymmetrical
most commonly seen in the left ventricle
Describe the pathophysiology behind hypertrophic cardiomyopathy
the thickened walls take up more room and don’t stretch as easily
this means the ventricles are less able to fill with blood
What happens to stroke volume in hypertrophic cardiomyopathy?
reduces, as not as much blood can fill, and therefore be pumped out, of the ventricle
Name a major complication of hypertrophic cardiomyopathy
heart failure - specifically, diastolic, as the problem is with the filling of ventricles
What is the venturi effect (in the context of HCM)?
the left ventricular outflow tract is obstructed by the hypertrophied septum
the changes in flow volume and pressure caused by this, pulls the anterior leaflet of the mitral valve towards the septum
Describe the murmur heard in hypertrophic (obstructive) cardiomyopathy
crescendo-decrescendo
similar to aortic stenosis murmur, but is more intense when standing compared to squatting
What is a bifid pulse?
this is where two pulses can be felt, in the case of HCM this is because of the movement of the mitral valve
Why does HCM have a high risk of fast arrythmias and sudden cardiac death?
This is because the larger muscles require a greater amount of oxygen
However, stroke volume is reduced, meaning the muscle is likely to become ischaemic
List some symptoms of HCM
fast arrythmias
dyspnoea
syncope
What is the inheritance pattern of HCM?
autosomal dominant, caused by a missense mutation
What genes are linked with HCM?
genes coding for sarcomeres
most commonly, the beta-myosin heavy chain
What disease is commonly associated with HCM?
Friedreich’s Ataxia - an autosomal recessive, neurodegenerative disease
What is the pharmacological management of HCM?
beta blockers for rate control
calcium channel blockers if these are not tolerated
What drug is contraindicated in HCM and why?
digoxin, as it increases contraction force, and could therefore increase any obstruction
What is the non-pharmacological treatment of HCM?
surgery
