Mitral stenosis Flashcards
What is mitral stenosis?
This is a narrow mitral valve making it difficult for the left atrium to push blood through to the ventricle.
BMJ: Mitral stenosis is a narrowing of the mitral valve orifice, usually caused by rheumatic valvulitis producing fusion of the valve commissures and thickening of the valve leaflets.
Describe the mitral stenosis murmur.
Mid-diastolic low pitched rumbling murmur - due to low velocity of blood flow.
Loudest over mitral valve
Opening snap (OS)
Loud S1 - due to thick valves requiring large systolic force to shut then shutting suddenly. You can palpate tapping apex beat due to loud S1.
Accentuated by patient lie on left
What kind of murmur is mitral stenosis?
Mid-diastolic low pitched rumbling murmur
Name 2 signs which mitral stenosis is commonly associated with.
Malar flush. This is due to back-pressure of blood into the pulmonary system causing a rise in CO2 and vasodilation.
Atrial fibrillation. This is caused by the left atrium struggling to push blood through the stenotic valve causing strain, electrical disruption and resulting fibrillation.
What are the risk factors for mitral stenosis?
- Streptococcal inection
- Female - x3 more likely to have mitral stenosis
- 40-50yrs usually first symptoms
Other:
- Ergot medication
- Serotogenic medication
- SLE
- Amyloidosis
- Bronchial carcinoid syndrome
What are the causes of mitral stenosis?
- Rheumatic Heart Disease (95%) - attack of RF causes thickening and retraction of the valve –> MR which progresses to MS when mitral leaflet commissures fuse and leaflets/sub-valvular apparatus thicken.
Other rarer causes:
- Prosthetic valve
- Mitral annular calcification
- Amyloidosis
- Congenital
- Use of ergot/serotonergic drugs e.g. fenfluramine
- SLE
- Carcinoid syndrome
- IE - vegetations increase risk of stenosis
What are the signs and symptoms of mitral stenosis?
Symptoms:
- dyspnoea
- orthopnoea
- paroxysmal nocturnal dyspnoea
- peripheral oedema
- Hx of rheumatic fever
Signs:
- low-pitched, rumbling murmur
- best heard in apex (palpable S1), in left lateral position
- accentuated by handgrip
- opening snap - as stiff valve opens
- AF may be present
- Malar flush
- rales suggest LVF
- raised JVP - in pulmonary hypertension/RVF
- signs of pulmonary hypertension and RHF (peripheral oedema and ascites)
What investigations would you do for mitral stenosis?
TTE + Doppler - definitive test for diagnosis of mitral stenosis. Hockey stick-shaped mitral deformity.
ECG - may show left atrial enlargement, RV hypertrophy, AF
CXR - double heart border indicating enlarged left atrium, prominent pulmonary artery +/- Kerley B lines
Dynamic exercise testing - determines severity to see if surgery required when diuretics fail to ameliorate symptoms. If pulmonary capillary wedge pressure or pulmonary artery pressure increase with exercise, the patient should be considered for valvotomy.
(Cardiac catheterisation should only be done if ECHO findings are inconclusive)
Summarise how you distinguish between diastolic murmurs.
Left atrial dilatation - LA hypertension
Pulmonary haemosiderosis (nodules throughout) - due to high pressures; not seen much here as mitral valves are replaced before this happens
What happens if you cannot have the murmur but there is a tapping apex and RV heave (i.e. signs of MS)?
Exercise the patient to exacerbate the stenosis causing the murmur
