Valvular Heart Disease Flashcards
what is stenosis?
narrowing of outlet so blood can’t get through
the valve isn’t opening properly
what is the effect of stenosis on heart?
heart therefore has to pump harder
can’t push the blood out, the pressure of the blood behind the stenotic valve is going to decrease ventricle therefore has to work harder
what happens to the flow of blood as a result of stenosis? what effect does this have?
the flow of blood following stenosis is reduced
if flow in coronary arteries is reduced then blood supply to the hypertrophic muscle may be compromised
what leads to stenosis?
thickening of valve cusps as a result of atherosclerosis
increased rigidity due to scarring
what is valve incompetence?
valves allow the blood to go forward but are loose and therefore don’t close resulting in back flow of blood
what is the effect of valve incompetence?
pump has to be pumped harder to get blood through valve because some of the blood will flow back
except a higher systolic pressure but lower diastolic
describe the composition of vegetation and how it forms
damage on a valve cusp that is a modified bit of intravascular material
platelets stick and thrombin can then accumulate
the valve may become damaged by infection, vasculitis then platelets and thrombin are deposited on top of that
what is the effect of vegetation?
valvs dont close properly
organisation of vegetation and fibrosis and calcification you can get distortion of valve = incompetence or it can be less mobile leading to it becoming stenosed
how does congenital heart disease cause valve stenosis and incompetence?
bicuspid aortic valve more likely to have problems with corners which in time could lead to stenosis
how do cardiomyopathies lead to valve problems?
hypertrophic heart, heart gets to big because you have a primary problem with myocardium causing the ring to become dilated causing the valves to open and cusps don’t close properly
extra workload on the heart increases O2 demand
what acquired conditions can lead to valve issues?
rheumatic fever, MI (valves don’t work because of damaged papillary muscles), age related, endocarditis
how does aortic stenosis form?
heavy calcification because of damage to cusps therefore you have platelets and fibrin deposited
organisation and calcification of fibrous tissue
what is aortic stenosis?
cusps of aortic valve can be fixed and blood struggles to get through because of stenosis but valve can leak blood back through because it is incompetent
what are the risks of aortic stenosis ?
incompetence- left heart working to push blood through, but blood flows back, harder to get blood to flow from R side to L because blood flowing back in left
L and R ventricular hypertrophy
O2 demand of coronary arteries increases, problems such as atherosclerosis O2 demand is high affects both sides
sudden death- if don’t get enough blood and if for a moment you don’t get enough blood to the brain you can drop= syncope or death
what are the main causes of aortic stenosis?
calcification of congenital bicuspid valve
rheumatic fever= damage and abnormal structure to the valve
senile calcification degradation- accumulation of damage
what causes aortic incompetence?
flapping valve or ring doesnt close
Marfan’s syndrome= cross bridge in collagen not been effective leads to stretchy floppy collagen hyper flexible vale efferents
rheumatic fever
infective endocarditis
what is aortic regurgitation?
increase the amount of blood=higher systolic
workload of heart goes up
what causes mitral valve incompetence?
cusp: infective endocarditis, marfan syndrome, rheumatic disease
papillary: post MI
valve ring: age
what is the risk of mitral valve incompetence?
heart will pump harder on the right side
what leads to Mitral stenosis?
congenital
post rheumatic fever
what does mitral stenosis cause?
restricts blood flow to the left ventricle
atrial fibrillation
right sided heart failure
pulmonary hypertension as a result of back pressure
what is infective endocarditis?
infection of valve with formation f thrombotic vegetations (platelets and fibrin)
vegetation becomes infected by being blood borne
its severity depends on the bug trapped within
how does infective endocarditis form?
bugs trapped are protected in vegetation because blood is moving so fast
bugs can therefore multiply
don’t get an accumulation of chemoattractant factors because blood constantly flows over
what are the risk factors of infective endocarditis?
rheumatic fever commonest reason for valves to be damaged and then secondary to damager become infected with infective endocarditis
valve damage=turbulence of flow and platelets stick, low grade damage can be infected later
bacteraemia- dental- bacteria enters blood supply and catch in injured vegetation
catheterisation- bacteraemia
what is rheumatic fever?
streptococcal infection
associated with scarlet fever
antibodies are made to attack infection however these cross react with host epitopes and there is damage to exposed collagen which could be in valve
how does rheumatic fever affect the heart?
multi spasm which affects the heart
what is the composition of vegetation?
platelets, fibrin, hard core thrombus this can protect bugs within
what are the local effects of infective endocarditis?
heart problems: valves may become worse, may perforate
what are systemic effects of infective endocarditis?
fever eliciting a generalised response
problems with kidney - blood urine
splinter haemorrhage
finger clubbing
what are the principles of diagnosis and treatment and prevention of infection endocarditis?
diagnosis=blood cultures
treatment=intravenous antibiotics
prophylaxis during procedures which may lead to a bacteraemia
