Mitral Stenosis

Question 1

define mitral stenosis?

Answer 1

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

=> leads to obstruction of blood flow from left atrium to left ventricle

Question 2

what is the most common cause of mitral stenosis?

Answer 2

rheumatic fever leading to rheumatic disease

During an attack of acute rheumatic fever the mitral valve becomes thickened and retracted leading to mitral regurgitation. However, years later, fusion of the mitral leaflet commissures and thickening of the leaflets and sub-valvular apparatus cause mitral stenosis.

Question 3

summarise the epidemiology of mitral stenosis?

Answer 3

incidence is declining because rheumatic fever is becoming more rare

Question 4

what are the rarer causes of mitral stenosis?

Answer 4

congenital mitral stenosis

SL

rheumatic arthritis

endocarditis

calcification due to ageing

amyloidosis

ergot medications

sertaogenic medications

Question 5

what are the risk factors for mitral stenosis?

Answer 5

streptococcal infection

female sex

ergot medications

seratogenic medications

Question 6

what are the symptoms of mitral stenosis?

Answer 6

can be asymptomatic

fatigue

SOB on exertion or lying down ( orthopnoea) - due to pulmonary congestion/ oedema when blood backs up into the pulmonary circulation

palpitations ( AF related ) due to LA working hard to pump blood into the ventricles and eventually working hard so it becomes asynchronous

Question 7

what are the rarer symptoms of mitral stenosis?

Answer 7

cough

haemoptysis

hoarseness ( due to compression of L. laryngeal by enlarged lA)

difficulty swallowing due to compression by dilated LA

Question 8

What are the signs of mitral stenosis?

Answer 8

malar flush

low volume pulse

may have central and peripheral cyanosis

• Thready pulse or irregularly irregular pulse (AF)
• Apex beat displaced and tapping
• Parasternal heave (RV hypertrophy + pulmonary HT)

• Auscultation
○ loud first heart sound with opening snap
○ mid-diastolic murmur (best heard in expiration)
○ PO evidence when examining lung base
○ As it becomes severe length of murmur increases and opening snap becomes closer to S2

Question 9

what are the investigations for mitral stenosis?

Answer 9

ECG

CXR

Trans-thoracic echo-

Question 10

what may be seen on the ECG for mitral stenosis?

Answer 10

may be normal

may see p mitral (broad bifid p wave caused by left atrial hypertrophy)

may see AF

evidence of right ventricular hypertrophy may be seen if there is severe pulmonary hypertension

Question 11

what can be seen on the CXR in mitral stenosis?

Answer 11

left atrial enlargement

cardiac enlargement

pulmonary congestion

mitral valve calcification ( occurs in rheumatic cases)

Question 12

what can be seen on the Echo in mitral stenosis?

Answer 12

assesses structural and functional impairments- hockey stick shaped mitral deformity

Question 13

which investigations should you consider for mitral stenosis and what will each investigation show?

Answer 13

trans-oesophageal- Echocardiography- presence of possible left atrial thrombus

cardiac catheterisation- high left atrial pressure, low left ventricular pressure, and low cardiac output

dynamic exercise testing-> pressures increase with exercise; pulmonary capillary wedge (PCW) >25 mmHg or pulmonary systolic pressure >60 mmHg

Question 14

what is dynamic exercise testing

Answer 14

Exercise response measured by echocardiography or cardiac catheterisation.

If PCW pressure or pulmonary artery pressure increase with exercise, the patient should be considered for valvotomy.

Question 15

what is PCWP?

Answer 15

Pulmonary capillary wedge pressure (PCWP) provides an indirect estimate of left atrial pressure (LAP)

Question 16

Briefly summarise what mitral stenosis results in?

Answer 16

Causes decreased filling of the left ventricle, while simultaneously increasing left atrial pressure, producing the syndrome of heart failure.

As disease progresses, pulmonary hypertension and right heart failure occur.

Mild disease can be treated symptomatically with diuretics. Moderate to severe disease requires mechanical correction of the valve obstruction by valvotomy, valve repair, or valve replacement.