Valvular Heart Disease - Pathophysiology, Presentation & Investigation Flashcards
What is the most anterior heart valve?
pulmonary valve
Which valve lies immediately posterior to the pulmonary valve?
aortic valve
How many cusps does the mitral valve have?
What are they called?
2
anterior and posterior cusps of mitral valve
What sort of conditions are the valves of the right side of the heart normally involved in?
congenital diseases/abnormalities
What are the three main causes of mitral stenosis?
- rheumatic heart disease
- congenital mitral stenosis
- systemic conditions
Which systemic conditions could lead to mitral stenosis?
2
- lupus
- rheumatoid arthritis
Explain how a streptococcal throat infection can cause mitral stenosis.
(3)
- mitral valve shares same antigens as streptococcal bacteria causing throat infection.
- systemic antibodies not only attack the bacteria, but also attack the mitral valve.
- leads to scarring of the valve = mitral stenosis.
What is the normal size of the mitral valve and what does it decrease to in mitral stenosis?
- normally 4-6cm squared.
- in stenosis, <2cm squared
What happens to the atrioventricular pressure gradient in mitral stenosis?
it increases
What happens to the left atrial pressure in mitral stenosis?
Explain this.
it increases
- blood return via pulmonary veins is greater than the volume of blood being pumped into the LV (due to narrower valve oriface) therefore LA pressure rises.
What happens to the pulmonary venous and capillary pressures in mitral stenosis?
Explain this.
it increases
Instead of being pumped into the LV, blood in the LA is flowing back through the pulmonary veins due to the increased pressure in the LA.
What happens to pulmonary vascular resistance (PVR) in mitral stenosis?
it increases
What happens to pulmonary arterial pressure in mitral stenosis?
What does this lead to?
it increases
pulmonary hypertension
What happens to the right side of the heart with mitral stenosis?
(3)
- pulmonary hypertension leads to pulmonary and tricuspid regurgitation - this causes right heart dilation
- leads to right heart failure.
What does the severity of mitral stenosis depend on?
2
- trans-valvular pressure gradient
- trans-valvular flow rate
What increases trans-valvular flow rate, increasing the severity of mitral stenosis?
(2)
- increased HR
- increased CO
When might heart rate increase, causing the severity of mitral stenosis to increase?
- pregnancy
- exercise
- acute illness
- atrial fibrilation
What are the clinical manifestations of mitral stenosis?
- dyspnoea
- haemoptysis
- 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?
2
- rupture of thin-walled veins in the lungs
- due to increased pressure
How can mitral stenosis cause systemic embolisation? and
What can this lead to?
- LA and LA auricle enlarge due, pressure increases
- blood stagnates, forms emboli
- emboli can lodge in common carotid a. and cause stroke.
How can mitral stenosis cause hoarseness of voice?
Pressure on left recurrent laryngeal nerve which innervated the voice box.
What might be found on clinical examination which would suggest mitral stenosis?
(6)
- Mitral facies
- normal pulse
- JVP: prominent a wave
- Tapping apex beat and diastolic thrill
- RV heave
- auscultation: faint murmur after S2
What is mitral facies?
red, blushed cheeks with cyanosed tissue around them
Why might a right ventricular heave be palpable in mitral stenosis?
- increased left atrial pressure
- increased pulmonary pressure
- right ventricular hypertrophy
What are the investigations carried out for mitral stenosis?
5
- CXR
- ECG
- cardiac catheterisation
Imaging:
- echocardiogram (best investigation)
- cardiac MRI
What will be seen on a CXR with mitral stenosis?
- LA atrial enlargement
i. e. enlarged heart borders
What will be seen on an ECG of mitral stenosis?
2
- may show higher R wave (RVH)
- P>0.12sec
What will be seen in an echocardiogram of mitral stenosis?
2
- thickening and scarring of leaflets
- fusion of the commissures (where leaflets meet)
What can be seen on cardiac MRI of mitral stenosis?
- left atrial dilatation
- LA>LV (very unusual)
What is the treatment of mitral stenosis?
6
- diuretics
- reduced Na intake
- atrial fibrillation and sinus rhythm restoration or ventricular rate control
- anti-coagulation
Surgical:
- 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)
- Infective endocarditis
- degenerative
- functional mitral regurgitation due to LV and annular dilatation.
What causes mitral valve prolapse?
- may be genetic predisposition
- degenerative, over 50s, men
What factors increase the annular dilatation (orifice) and therefore the volume regurgitated through the mitral valve?
(3)
- preload
- afterload
- LV contractility
How does the left ventricle of the heart adapt to increased volume entering it from regurgitation in chronic mitral regurgitation?
(3)
- EDV increases
- ESV normal
- LVH
How does the left ventricle of the heart adapt to increased volume entering it from regurgitation in acute mitral regurgitation?
(2)
- ESP/ESV decrease
- wall tension decrease
What happens to the left atrium in chronic mitral regurgitation if it adapts/complys?
(3)
- enlargement of LA
- less changes in pulmonary vasculature
- may develop AF
What happens to the left atrium in chronic mitral regurgitation if it does not adapt/comply?
(3)
- LA pressure rise
- atrial myocardium thickens
- PVR increases
- develops pulmonary hypertension
- remodelling of pulmonary vasculature
What are the acute causes of mitral valve regurgitation?
Valve, chordae tendinae or papillary muscle perforation.
What are the symptoms/clinical manifestations of acute mitral valve regurgitation?
(2)
- breathlessness (as a result of pulm. oedema)
- cardiogenic shock
What is cardiogenic shock?
heart suddenly can’t pump enough blood to meet your body’s needs
Why is acute mitral regurgitation a clinical emergency?
- blood floods back into an atrium which is unadapted to the increased volume and pressure.
What are the clinical presentations of chronic mitral regurgitation?
(5)
- fatigue
- exhaustion
- right heart failure
- dyspnoea
- palpitations
What causes fatigue and exhaustion in chronic mitral regurgitation?
Low CO
What cause dyspnoea and palpitations in mitral regurgitation?
atrial fibrillation
What are the signs of mitral regurgitation?
5
- normal pulse (low in HF)
- JVP: prominent with R hypertrophic failure)
- hyperdynamic apex beat
- right ventricular heave
- murmur during systole
What will be heard on auscultation in mitral regurgitation?
- reduced S1 (leaflets not in close contact)
Which investigations are used to diagnose mitral regurgitation?
(4)
- ECG
- CXR
- Echocardiogram
- cardiac MRI
What does mitral regurgitation show up as on ECG?
2
- P wave >0.12 sec/tall = LA enlargement
- prominent R wave in R precordial leads = RVH
What will be seen in a CXR in mitral regurgitation?
3
- cardiomegaly
- LA enlargement
- calcification of mitral annulus
What can an echocardiogram be used to assess in mitral regurgitation?
(2)
- leaflet, chordae or papillary dysfunction, annular disease
- severity of MR and pulmonary artery pressure.
What can a cardiac MRI be used to assess in mitral regurgitation?
(2)
- accurate cardiac volumes (EDV)
- volumetric analysis of regurgitation volume
What are the non-surgical treatments for acute mitral regurgitation?
(3)
Reduce preload/afterload
- nitroprusside (NO = vasodilator)
- doputamine (B1-agonist, increases contractility but not HR)
- IABP (intra-aortic balloon pump, decreases afterload)
What are the non-surgical treatment for chronic mitral valve regurgitation?
there isn’t much
What are the surgical interventions for mitral valve regurgitation?
(2)
- MV apparatus repair
- MVR
What are the causes of aortic valve stenosis?
3
- 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?
(3)
- inflammatory process
- thickening and calcification of the cusps.
What is degeneration of the aortic valve associated with?
atherosclerosis
Describe the pathophysiology of aortic stenosis?
- ventricular systolic P increase
- increased LVH/mass
- increased left ESP
- increased LA pressure
- pulmonary hypertension
- increased O2 use
- leads to ischaemia
- LV failure
When do symptoms of aortic stenosis commonly occur?
after a long asymptomatic phase of about 50-60 years
What are the cardinal symptoms of aortic stenosis?
4
- angina
- syncope
- Breathlessness on exertion
- Heart failure
what are the clinical manifestations of aortic stenosis?
5
- slow/rising pulse
- JVP: present in RHF, low BP
- vigorous apex beat (because of LVH)
- RV heave
- systolic murmur with crescendo-decrescendo 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?
4
- ECG
- CXR
- Echocardiogram
- cardiac MRI
What does an ECG of aortic stenosis look like?
2
- signs of LVH
- ST/T changes (LV strain)
What will a CXR show on a patient with aortic stenosis?
calcification of aortic valve, but not specific to
What can an echocardiogram be used to assess in aortic stenosis?
(3)
- 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?
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?
6
Aorta:
- aortic dilatation
- connective tissue disorders
Leaflets:
- bicuspid aortic valve
- rheumatic heart disease
- endocarditis
- moxymatous degeneration (prolapse)
Describe the pathology of aortic regurgitation.
7
- LV accommodates both SV and regurgitated V
- increased EDV
- increased systolic pressure
- LVH/dilation
- increased O2 consumption
- myocardial ischaemia
- LV failure
What are the symptoms of chronic aortic regurgitation?
2
- Long asymptomatic phase
- Exertional breathlessness
Why is acute aortic regurgitation a medical emergency?
3
- sudden backflow of blood into an unadapted LV.
- pressure back into LA
- to PV
- cardiogenic shock
What are the clinical signs of aortic regurgitation?
4
- pulse = large/falling
- wide pulse pressure (systolic high, diastolic low)
- hyperdynamic and displaced apex beat
- early diastolic, decrescendo murmur
Why does the pulse of a patient with an 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?
(4)
- ECG
- CXR
- Echocardiogram
- cardiac MRI
What is seen on a ECG of a patient with aortic regurgitation?
(2)
ST/T changes (LV strain), LA dilation
What can a CXR show in aortic regurgitation?
cardiomegaly (in chronic cases)
what can be seen on an echocardiogram in aortic regurgitation?
(3)
- thickening/prolapsing of cusp
- LV function, hypertrophy and dilatation
- Doppler haemodynamics to assess regurgitant flow
What are the treatments of aortic regurgitation?
vasodilator therapy (delays need for surgery)
