valvular heart disease Flashcards
what is the most anterior heart valve?
pulmonary valve
what is the valve lies immediately posterior to the pulmonary valve?
aortic valve
how many cusps does the mitral valve have? and what are they called?
2
anterior and posterior valves
what sort of conditions are the valves of the right side of the heart normally involved in?
congenital diseases
what are the three main causes of mitral stenosis?
rheumatic heart disease
congenital mitral stenosis
systemic conditions (SLE and RA)
what systemic conditions causes mitral stenosis?
- systemic lupus erythematosus
- rheumatoid arthritis
describe how a groups A beta haemolytic strep throat infection cancause mitral strenosis?
antigens on the bacteria are shared with antigens on the mitral valve. So the immune response to the bacteria also attacks the mitral valve. this leads to scarring of the valve and stenosis
what is the normal size of the mitral valve and what does it decrease to in stenosis?
normally 4-6cm squared
<2cm squared in stenosis
what happens to the atrio-ventricular pressure gradient in mitral stenosis?
increases
what happens to the left atrial pressure in mitral stenosis? why?
increases, due to having to pump through narrower oriface
what happens to the pulmonary venous and capillary pressures in mitral stenosis? why?
increases, as blood, instead of going in to the ventricle flows back in to the pulmonary circulation
what happens to pulmonary vascular resistance in mitral stenosis?
increases
what happens to pulmonary arterial pressure in mitral stenosis? and what does this lead to?
increases, leads to pulmonary hypertension
what happens to the right side of the heart with mitral stenosis?
dilatation because of pulmonary hypertension leaidng to of tricuspid regurgitation and pulmonary regurgitation
what does the severity of mitral stenosis depend on?
- trans-valvular pressure gradient
- trans-valvular flow rate (affected by cardiac output and HR)
what increases trans-valvular flow rate, increasing the severity of mitral stenosis?
increased heart rate, increased cardiac output
when might heart rate increase, causing the severity of mitral stenosis to increase?
exercise
acute illness
pregnancy
atrial fibrillation
what are the clinical manifestations of mitral stenosis?
dyspnoea haemoptisis systemic embolisation infective endocartitis chest pain hoarseness
what will cause dyspnoea in mitral stenosis?
on mild exertion from pulmonary oedema
why might mitral stenosis cause haemoptysis?
when there is rupture of thin-walled veins in the lungs from increased pressure
why might mitral stenosis cause systemic emboli? and what can this lead to?
as left atrial and left auricle enlargement can lead to emboli which can lodge in the carotid artery, causing a stroke.
why might mitral stenosis cause hoarsness of voice?
compression of reccurent laryngeal nerve
what are the findings on examination of mitral stenosis?
mitral facies normal pulse prominant a-wave in JVP normal apex beat diastiolic thrill RV heave faint murmur after S2 on ausculatation
what is mitral facies?
red, blushed cheeks with cyanosed tissue around them
why might a rv heace be palpable in mitral stenosis?
increased pulmonary pressure causes rv hypertrophy
what are the investigations carried out for mitral stenosis?
CXR ECG cardiac catheterisation echocardiogram (best investigation) cardiac magnetic resonance imaging
what will be seen on a cxr with mitral stenosis?
left atrium enlargement
what will be seen on an ECG of motral stenosis?
RVH, P>0.12sec
what will be seen in echocardiogram of mitral stenosis?
- thickening and scarring of leaflets
- fusion of the commissures
what can be seen on cardiac MRI of mitral stenosis?
left atrial dilatation
what is the treatment of mitral stenosis?
- diuretics and restriction if sodium intake to decrease strain on chambers
- atrial fibrillation and sinus rhythm restoration or ventricular rate control
- anticoagulation
- valvotomy
- mitral valve replacement
why might atrial fibrilation occur in mitral stenosis?
atrial dilatation causes abnormal electrical activity
what are the causes of mitral regurgitation?
- Rheumatic Heart Disease
- Mitral valve prolapse (MVP)
- IE
- Degenerative
- Functional mitral regurgitation due to left ventricular and annular dilatation
what causes mitral valve prolapse?
degeneration of the valve, occurs at about 50.
there is genetic susceptibility
myxomatous valve disease
what causes degeneration of the mitral valve causing regurgitation?
old age causing thickening and fibrosis
what factors increase the annular dilatation and so volume regurgitated through the mitral valve?
preload
afterload
LV contractility
how does the left ventricle of the heart adapt to increased volume entering it from regurgitation and stroke volume together in chronic mitral regurgiation?
eccentric hypertrophy occurs, where volume of ventricle increases as well as wall thickness.
what happens to the left atrium in chronic mitral regurgitation if it adapts?
enlargement of the left atrium causing reduced changes to pulmonary vasculature but can develop atrial fibrillation
what happens in chronic mitral regurgitation if the left atrium does not adaptadapts?
- marked pressure rise leading to thickening of of atrial myocardium
- increased pulmonary venour resistance
- so pulmonary vascular remobelling from pulmonary hypertension
what are the acute causes of mitral valve regurgitation?
valve, chordal or papillary muscle perforation
what are the clinical manifestations of acute mitral valve regurgitation?
breathlessness
pulmonary oedema
cardiogenic shock
what is cardiogenic shock?
condition in which your heart suddenly can’t pump enough blood to meet your body’s needs.
why is acute mitral regurgitation a clinical emergency?
as blood floods back into an atrium which is unadapted to the increased volume and pressure
what are the clinical presentations of chronic mitral regurgitation?
fatigue
exhaustion (from low cardiac output)
right heart failure
dyspnoea or palpitations (due to atrial fibrillation)
what causes fatigue and exhaustion in chronic mitral regurgitation?
low cardiac output
what cause dyspnoea and palpitations in mitral regurgitation?
atrial fibrillation
what are the signs or mitral regurgitation?
normal pulse (or redused in heart failure)
JVP- prominent if right hypertrophic failure is present
brisk and hyperdynamic apex beat
right ventricular heave
murmur during systole
which investigations are used to diagnose mitral regurgitation?
ECG
CXR
Echocardiogram
cardiac MRI
what does mitral regurgitation show up as on ECG?
- P wave >0.12 sce and tall showing left atrial enlargement
- prominent R wave in R precordial leads showing RVH
what will be seen in a CXR in mitral regurgitation?
- cardiomegaly
- LA enlargement
- calcification of mitral annulus
what can an echocardiogram be used to assess in mitral regurgitation?
-leaflet, chordae or papillary dysfunction
annular disease
-severity of MR (and papillary muscle)
what can a cardiac MRI be used to assess in mitral regurgitation?
- accurate cardiac volumes
- volumetric analysis of regurgitation volume
what are the non-surgical treatments for acute mitral regurgitation?
reduce preload and afterload
- nitroprusside (converted in to NO which is a vasodilator to decrease preload and afterload)
- doputamine ( Beta 1 agonist, increases contractility but not rate)
- IABP (intra-aortic balloon pump, decreases afterload)
what are the non-surgical treatment for chronic mitral valve regurgitation?
there arent any
what are the surgical interventions for mitral valve regurgitation?
mitral valve apparatus repair
mitral valve replaecement
what are the causes of aortic valve stenosis?
- degeneration
- rheumatic heart disease
- congenital bicuspid aortic valve
what does bicuspid aortic valve cause?
aortic stenosis or regurgitation
how dies rheumatic heart disease affect the aortic valve to cause stenosis?
- adhesion and fusion of the commissures
- retraction and stiffening of the free cusp margins
what are the degenerative changes in the aortic valve that cause stenosis?
inflammatory process resulting in thickening and calcification of the cusps.
what is degeneration of the aortic valve associated with?
atherosclerosis
describe the pathophysiology of aortic stenosis?
- increased left ventricular systolic pressure as has to push blood through narrower valve
- concentric hypertrophy of LV and increased mass
- increased left ventivular end diastolic pressure means that left atrial pressure also increases
- this leads to pulmonary hypertension
- increased myocardial oxygen consumption
- lead to ischaemia
- ultimately LV failure
when do symptoms of aortic stenosis commonly occur?
after a long asymptomatic phase of about 50 years
what happends to the prognosis of patients with aortic stenosis once in becomes syptomatic?
their prognosis decreases rapidly. so treatment is required quickley
what are the cardinal symptoms of aortic stenosis?
chest pain (angina)
-syncope and dizziness (exertional presyncope)
-breathlessness on exertion
heart failure
what are the signs of aortic stenosis?
- small, slowly rising pulse
- JVP prominent if RH failure present, low BP
- vigorous and sustained apex beat (because of LVH)
- rv heave
- systolic murmur with crescendo-decsescendo sound
where will a murmur form aortic stenosis radiate to?
the carotid arteries
where will a murmur from mitral regurgitation radiate to?
the axilla
what are the investigations for aortic stenosis?
ECG
CXR
echocardiogram
cardiac MRI
what does an ECG of aortiv stenosis look like?
- signs of LVH hypertrophy
- ST and T changes from left ventricular strain
what will a CVR show on a patient with aortic stenosis?
calcification of aortic valve
what can an echocardiogram be used to assess in aortic stenosis?
- aortic valve cusp motility
- LV function and hypertrophy
- Doppler haemodynamic assessment of pressure gradient and aortic valve area
to who are the non-surgical treatment of aortic valve stenosis limited to?
those who develop heart failure
what is the surgical treatment of aortic stenosis?
aortic valve replacement or repair
what are the causes of aortic regurgitation?
- aortic dilatation (Marfans, hypertension)
- connective tissue disorders
- bicuspid aortic valve
- rheumatic heart disease
- endocarditis
- moxymatous degeneration (prolapse)
describe the pathology of aortic regurgitation
1, the left ventricle has to accommodate both stroke volume and regurgitated volume
- so increased pressure in left ventricle during systole
- LV hypertrophy and dilatation
- increased oxygen consumption of LV
- myocardial ischaemia
- heart failure
what are the symptoms of aortic regurgitation?
exertional breathlessness
however there is a long asymptomatic period
why is aortic regurgitation a medical emergency?
there is sudden backflow of blood into an unadapted left ventricle this is poorly tolerated.
what are the clinical signs of aortic regurgitation?
- pulse is large volume and collapsing
- wide pulse pressure
- hyperdynamic and displaced apex beat
- early diastolic, decrescendo murmur
why does the pulse of a patient with a aortic regurgitation have a large volume?
LVH pushes a lot of blood out
why does the pulse if a patient with aortic regurgitation collapse?
as blood travels back into the ventricle through the aortic valve in diastole
what are the investigations carried out for aortic regurgitation?
ECG
CXR
echocardiogram
cardiac MRI
what is seen on a ECG of a patient with aortic regurgitation?
- ST or T changes associated with LV strain
- left atrial dilatation
what can a CXR show in aortic regurgitation?
cardiomegaly (in chronic cases)
what can be seen on an echocardiogram in aortic regurgitation?
- AV cusp anatomy: thickening, prolapsing, number of cusps, vegetations
- LV function, hypertrophy and dilatation
- Doppler haemodynamics to assess regurgitant flow
what are the treatments of aortic regurgitation?
vasodilator therapy (delays need for surgery)
what are the surgical treatments for aortic regurgitation?
aortic replacement and repair