valvular heart disease Flashcards
describe the mitral valve?
Fibrous annulus, anterior and posterior leaflets, chordae, tendinae and papillary muscles
what is the most common cause of mitral stenosis?
- rheumatic heart disease secondary to previous rheumatic fever due to infection with group A beta-hemolytic streptococcus
- women > men
- inflammation-> commissural fusion and reduction in mitral valve orifice->doming pattern on echo -> thickening of valve, cusp fusion, calcium deposition, narrowed stenotic valve orifice and immobility of valve cusps
what are the other causes of mitral stenosis?
- Lutemacher’s syndrome
- Congenital mitral stenosis
- Carcinoid tumours metastasizing to lung or primary bronchial carcinoid
- what is the normal mitral valve orifice area
2. and what is it in a patient with mitral stenosis?
- 4-6cm2
2. <1cm2
describe the pathophysiology of mitral stenosis?
- mitral valve orifice reduced
- for cardiac output to be maintained the left atrial pressure increases and left atrial hypertrophy and dilatation occur
- increase in pulmonary venous, pulmonary arterial and right heart pressure increases
- development of pulmonary oedema especially when in AF and tachycardia
- this is prevented by alveolar and capillary thickening and pulmonary arterial vasoconstriction
- pulmonary hypertension causes right ventricular hypertrophy, dilation and failure with tricuspid regurgitation
where is the mitral valve located?
left side of the heart between atrium and ventricle
when will a patient with mitral stenosis start to experience symptoms?
- until valve orifice is moderately stenosed (area=2cm2)
- usually not till several decades after attack of rheumatic fever
what are the symptoms of mitral stenosis and what causes them?
- progressive severe dyspnoea (pulmonary venous hypertension and recurrent bronchitis)
- productive cough-blood, frothy sputum, frank haemoptysis
- weakness, fatigue and abdominal swelling due to right heart failure due to pulmonary hypertension
- palpitations due to large atrium and AF
what signs would be seen In the face of a patient with mitral stenosis?
malar flush (bilateral, cyanotic, dusty pink discolouration over upper cheeks due to arteriovenous anastomoses and vascular stasis
describe the pulse of a patient with mitral stenosis?
small volume pulse
usually regular
mostly in sinus rhythm but may develop AF
what signs would be seen in jugular veins in a patient with mitral stenosis?
- if right heart failure develops-obvious distension of jugular veins
- if pulmonary hyertension or tricuspid stenosis present then ‘a wave’ will be prominent
what signs would be noted on palpation in a patient with mitral stenosis?
tapping impulse felt parasternally on left
what would be the auscultation findings in a patient with mitral stenosis?
- loud first heart sound if mitral valve is pliable
- opening snap heard due to increased left atrial pressure, followed by a low pitched rumbling mid diastolic murmur (best heard when patient lies on left side)
- if in sinus rhythm-louder at end of diastole.
- severity of mitral stenosis is judged based on criteria
what criteria is used to judge the severity of mitral stenosis?
- presence of pulmonary hypertension (severe, right ventricular heave)
- closeness of opening snap to second heart sound proportional to severity
- length of mid-diastolic murmur proportional to severity
- as valve cusps become immobile the loud first heard sound softens and opening snap disappears
what investigations should be considered in a patient with mitral stenosis?
- CXR
- ECG
- echo
- cardiac magnetic resonance
- cardiac catheterisation
what are CXR findings in a patient with mitral stenosis?
- small heart and enlarged left atrium
- usually have pulmonary venous hypertension
- calcified mitral valve
- signs of pulmonary oedema
what are ECG findings in patients with mitral stenosis?
- in sinus rhythm will show a bifid p wave due to delay of left atrial activation
- AF usually present
- as disease progresses-ECG may show right ventricular hypertrophy (right axis deterioration and tall R waves in V1)
what is the purpose of echo in a patient with mitral stenosis?
- Determine left and right atrial and ventricular size and function
- Severity of mitral stenosis can be defined by planimetry of the mitral valve area.
- Wilkins score-determine if valve is suitable for percutaneous valvotomy
- Continuous wave doppler can estimate pulmonary artery pressure
what is the purpose of cardiac magnetic resonance in patients with mitral stenosis?
show mitral valve anatomy
describe the role of cardiac catheterisation in patients with mitral stenosis?
- only used if co-existing cardiac problem suspected
- Right heart catheterisaton may be required to determine pulmonary artery pressure
what are the treatment options for mitral stenosis?
- mild may not need treatment
- early symptoms such as mild dyspnoea can be treated with low dose diuretics
- pulmonary hypertension-surgical relief
- operative measures
what are the 4 operative measures used in treatment of mitral stenosis?
- trans-septal balloon valvotomy
- closed valvotomy
- open valvotomy
- mitral valve replacement
describe trans septal balloon valvotomy?
- Catheter into right atrium via femoral vein under local anaesthetic in cardiac catheter laboratory
- Interatrial septum is punctured and catheter advanced into left atrium and across mitral valve
- Balloon is passed over catheter to lie across the valve and inflated
- Can result in regurgitation and need valve replacement
what patients is trans septal balloon valvotomy good in?
Good for patients with pliable valves with little involvement of subvalvular apparatus and with minimal mitral regurgitation