Valvular heart disease - mitral stenosis Flashcards
4 valves
atrio ventricular valves - move blood from atria to ventricles
* mitral / bicuspid (LAV) = 2 cusps (only 1 anterior cusp, others have 2)
* tricuspid (RAV) = 3 cusps
these AV valves are attached to chordae tendinae
semi lunar valves - move blood from the ventricles to the lungs + body
* aortic (between LV and aorta) = 3 cusps
* pulmonary (between RV and pulmonary artery) = 3 cusps
first heart sound caused by
mitral / bicuspid = LAV
tricuspid = RAV
second heart sound caused by
SL valves
aortic
pulmonary
valve defects can either be
valve doesn’t open
- obstructed bloodflow
- STENOSIS
valve doesn’t close
- back leakage
- REGURGITATION
mitral stenosis
structural anomoly of the mitral valve
resulting in a narrow valve opening
so obstructed blood flow across the mitral valve
reduces blood flow from the LA to the LV
aetiology - main cause
due to rheumatic heart disease
following PREVIOUS RHEUMATIC FEVER
(from an infection with group A b-haemolytic streptococcus, common in LIC)
rheumatic fever causes
fusion of the mitral valve (2 cusps)
so harder for blood to flow from LA to LV
other causes of mitral stenosis
- congenital
- AI diseases - SLE, RA
- prosthetic valves
- mitral annular calcification - if extensive, more commonly in elderly pt and those with ESRD
- carcinoid tumours metastasizing to the lungs or primary bronchial carcinoid (carcinoid/endocardial fibroelastosis)
- mucopolysaccharides
- Lutembacher’s syndrome (combo of acquired mitral stenosis + atrial septal defect)
peak incidence in
women
LIC - more common epidemic for rheumatic fever
pathophysiology
INCREASES LA PRESSURE
* blood backflows into the lungs, can’t be ejected
* increases pulmonary capillary pressure
* causing pulmonary oedema and pulmonary hypertension (and dysponea - trouble breathing)
* causes backward HF and RV hypertrophy
OBSTRUCTS BLOODFLOW INTO THE LV
* limited diastolic filling of the LV
* decreased SV (end-diastolic LV volume)
* decreased CO
* forward HF
LA DILATION
* rhythm can deteriorate to AF w/ tachycardia - increases risk of thrombus formation and stroke
* can compress oesophagus and cause dysphagia
symptoms
so symptoms begin when <2cm
normal mitral valve opening is 4-6cm
PULMONARY HYPERTENSION causes:
* worsening dysponea (+ due to pulmonary oedema)
* haemoptysis (cough productive of bloody, frothy sputum if ruptured thin-walled, dilated bronchial veins)
* RHS HF w/ weakness, fatigue, abominal or lower limb swelling
INCREASED LA PRESSURE causes:
* AF causes palpitations and eventually systemic emboli
* hoarseness (compresses RLN)
* dysphagia (compresses oesophagus)
* bronchial obstruction
OTHERS:
* fatigue
* palpitations
* chest pain
* systemic emboli
* IE (rare)
* RHS HF
* PND (paroxysmal nocturnal dysponea)
* orthopnea
* haemoptysis
signs
FACE
* malar flush = bilateral, cyanotic or dusky pink discolouration over the upper cheeks (due to reduced CO w/ arteriovenous anastomoses and vascular stasis)
PULSE
* small volume pulse
* starts as ** regular** (sinus rhythm) but deteriorates into irregularly irregular (AF)
JUGULAR VEINS
* RHS HF can cause JV distension
* pulmonary hypertension/tricuspid stenosis so a-wave is present, until AF occurs
PALPATION
* palpable S1 as a tapping, non-displaced apex beat
* RV heave
* extra sustained parasternal impulse due to RV hypertrophy = tapping impulse parasternally on LHS due to palpable 1st heart sound combined w/ LV backward displacement produced by an enlarging RV
AUSCULTATION
* loud S1 if mitral valve is flexible (not if calcified)
* opening snap heard after S2 as valve opens with force of increased LA pressure
* then a low-pitched, rumbling MID-DIASTOLIC murmur (heard with bell of stethoscope at apex beat (5th left IS midclavicular line) best heard when pt lies on LHS in expiration
* if pt has sinus rhythm, murmur is louder at the end of diastole due to atrial contraction (pre-systolic accentuation)
* pulmonary hypertension can cause pulmonary valve regurgitation which causes an early diastolic murmur in the pulmonary area (Graham Steell murmur)
if more severe mitral stenosis
- increased length of mid-diastolic murmur
- opening snap becomes closer to S2
complications
- condition progresses to valve thickening
- cusp fusion
- calcium deposition
- a severely narrowed (stenotic) valve orifice
- progressive immobility of the valve cusps
diagnosis
ECHO = TTE (transthoracic echocardiography)
- shows LA size and degree of thickening, calcification and mobility of the mitral leaflets
- CROSS SECTIONAL AREA OF MITRAL VALVE <1CM
- provides enough information for routine management
can also use TOE (trans-oesophageal echocardiography)
- shows LA thrombus
- carries out detailed assessment before considering surgical or percutaneous intervention
- before PMC/after an embolic episode/if TTE provides insufficient information
other investigations
- CXR
- ECG
- use Wilkins score - echocardiograph assessment of the mitral valve (leaflet mobility, valve thickening, valve calcification and subvalvular apparatus)
