Mitral valve disease

Question 1

What is mitral stenosis?

Answer 1

Mitral valve narrowing causing obstruction to blood flow from the left atrium to the left ventricle.  

Question 2

What are the different causes of mitral stenosis?

Answer 2

1. MAIN CAUSE: Rheumatic Heart Disease (90% of cases) 
2. Rare causes of mitral stenosis: 
   - Congenital mitral stenosis 
   - SLE 
   - Rheumatoid arthritis 
   - Endocarditis 
   - Atrial myxoma 
   - Mitral annular calcification (age-related)
   - Mucopolysaccharidosis (metabolic disorder affecting connective tissue)

Question 3

What are the presenting symptoms of mitral stenosis?

Answer 3

1. May be ASYMPTOMATIC 
2. Fatigue 
3. Shortness of breath on exertion 
4. Orthopnoea (shortness of breath (dyspnea) that occurs when lying flat)
5. AF causing palpitations 
6. Rare symptoms: 
   - Cough 
   - Haemoptysis 
   - Hoarseness caused by compression of left recurrent laryngeal nerve by an enlarged left atrium 
7. Dyspnoea - most common symptom (70% of patients), due to raised left atrial pressures and subsequent pulmonary venous hypertension
8. Chest pain - can occur as a result of pulmonary hypertension and R ventricular hypertrophy, or due to AF with fast ventricular response.
9. Thromboembolism (cerebral or systemic) - secondary to AF
10. Peripheral oedema / abdominal discomfort (hepatomegaly) - due to right heart failure

Question 4

What signs of mitral stenosis can be found on examination?

Answer 4

• Peripheral cyanosis 
• Apex beat undisplaced and tapping 
• Parasternal heave (due to right ventricular hypertrophy secondary to pulmonary hypertension) 
• Loud S1 with opening snap 
• Mid-diastolic murmur 
• Evidence of pulmonary oedema on lung auscultation (if decompensated) 
• Mitral facies (malar flush) - cutaneous vasodilation due to carbon dioxide retention
• Low volume pulse
• Atrial fibrillation (irregularly irregular pulse)
• Elevated JVP (prominent ‘a’ wave due to raised right atrial pressure, or absent ‘a’ wave in AF)
• Inspiratory crepitations (pulmonary oedema) and other signs of right heart failure

Question 5

What investigations are used to diagnose/ monitor mitral stenosis?

Answer 5

1. ECG:
   - May be NORMAL 
   - p mitrale (broad bifid p wave [m shaped] caused by left atrial hypertrophy) 
   - May see AF
   - RVH if there is severe pulmonary hypertension 
2. CXR:
   - Left atrial enlargement 
   - Cardiac enlargement 
   - Pulmonary congestion 
   - Mitral valve calcification (occurs in rheumatic cases) 
3. Echocardiography:
   - Assesses functional and structural impairments 
   - Transoesophageal echocardiogram (TOE) gives a better view 
4. Cardiac Catheterisation:
   - Measures severity of heart failure  

Question 6

How is mitral stenosis managed?

Answer 6

1. Asymptomatic → no therapy required, monitor with regular echocardiograms
2. Symptomatic (valve area <1.5 cm²)→ balloon valvotomy (or valve replacement)
   - Diuretics → furosemide (if signs of pulmonary oedema)

Question 7

What is mitral regurgitation?

Answer 7

Retrograde flow of blood from left ventricle to left atrium during systole 

Question 8

What are the different causes of mitral regurgitation?

Answer 8

1. Rheumatic heart disease(MOST COMMON) 
   - Mitral valve prolapse (young women) - connective tissue of the leaflets and surrounding tissue are weakened (myxomatous degeneration).
   - Connective tissue disease (e.g. Ehlers-Danlos syndrome, Marfan’s syndrome) - floppy valve 
   - Heart attack
   - Left sided heart failure
2. Acute onset: 
   - Infective endocarditis 
   - Trauma 
   - Papillary muscle rupture or dysfunction (secondary to MI, IHD or cardiomyopathy) 

Question 9

What are the presenting symptoms of mitral regurgitation?

Answer 9

• Acute MR- may present with symptoms of left ventricular failure 
• Chronic MR- may be asymptomatic or present with: 
• Exertional dyspnoea 
• Palpitations if in AF 
• Fatigue 
• Mitral Valve Prolapse- asymptomatic or atypical chest pain or palpitations 

Question 10

What signs of mitral regurgitation can be found on physical examination?

Answer 10

1. Pulse may be irregularly irregular(if in AF) 
2. Laterally displaced apex beat with thrusting (due to left ventricular dilation) 
3. Pansystolic murmur 
   - Loudest at apex beat (best heard on expiration) 
   - Radiating to the axilla 
4. Soft S1 
5. S3 may be heard due to rapid ventricular filling in early diastole 
6. Signs of left ventricular failure in acute mitral regurgitation 
7. Mitral Valve Prolapse: 
   - Mid-systolic click 
   - Late systolic murmur 
   - The click moves towards S1 when standing and away when lying down 

Question 11

What investigations are used to diagnose/ monitor mitral regurgitation?

Answer 11

1. ECG 
   - NORMAL 
   - May show AF or p mitrale(indicates left atrial hypertrophy) 
2. CXR 
   - ACUTE mitral regurgitation may produce signs of left ventricular failure 
   - CHRONIC mitral regurgitation shows: 
   - Left atrial enlargement 
   - Cardiomegaly (due to LV dilation) 
   - Mitral valve calcification (if rheumatic heart disease is the cause) 
3. Echocardiography 
   - Performed every 6-12 months in moderate-severe MR 
   - Allows assessment of LV ejection fraction and end-systolic dimension 

Question 12

How is mitral regurgitation managed?

Answer 12

• Valve Repair or Replacement
• Heart Failure Management → nitrates and diuretics (furosemide)