Mitral regurgitation

Question 1

define mitral regurgitation?

Answer 1

retrogade flow of blood from left ventricle to left atrium during systole due to mitral valve insufficiency

Question 2

briefly describe the cause of mtiral regurgitation?

Answer 2

The mitral valve apparatus consists of anterior and posterior leaflets, chordae tendineae, anterolateral and posteromedial papillary muscles, and mitral annulus. Any aberrations of the mitral valve apparatus, due to mechanical, traumatic, infectious, degenerative, congenital, or metabolic causes, may lead to mitral regurgitation (MR).

Question 3

outline the cause/ risk factors formitral regurgitation?

Answer 3

Rheumatic heart disease (MOST COMMON GLOBALLY)

• While this is uncommon in developed countries, rheumatic fever can cause inflammation of the valves and therefore result in mitral regurgitation.

Infective endocarditis

• When vegetations from the organisms colonising the heart grow on the mitral valve, it is prevented from closing properly. Patients with abnormal valves are more likely to develop endocarditis as opposed to their peers

Renal dysfunction

Prior MI increases risk

Mitral valve prolapse

• Occurs when the leaflets of the mitral valve is deformed so the valve does not close properly and allows for backflow. Most patients with this have a trivial degree of mitral regurgitation.

Papillary muscle rupture or dysfunction (secondary to IHD or cardiomyopathy)

• Following coronary artery disease or post-MI: if the papillary muscles or chordae tendinae are affected by a cardiac insult, mitral valve disease may ensue as a result of damage to its supporting structures.

Chordal rupture and floppy mitral valve associated with connective tissue disease (e.g. Ehlers-Danlos syndrome, Marfan’s syndrome)

Functional: LV dilatation

Annular calcification (elderly)

Congenital

dilated Cardiomyopathy

Appetite suppressants e.g. fenfluramine

Question 4

what are the presenting symptoms of mitral regurgitation?

Answer 4

Acute MR - may present with symptoms of left ventricular failure e.g SOB

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 5

what are the signs of mitral regurgitation on physical examination?

Answer 5

Pulse may be irregularly irregular (if in AF)

Laterally displaced apex beat with thrusting (due to left ventricular dilation)

Pansystolic murmur

• Loudest at apex beat
• Radiating to the axilla
• Soft S1
• S3 may be heard due to rapid ventricular filling in early diastole

Signs of left ventricular failure in acute mitral regurgitation

Mitral Valve Prolapse

• Mid-systolic click
• Late systolic murmur
• The click moves towards S1 when standing and away when lying down

Question 6

What are the appropriate investigations for mitral regurgitation?

Answer 6

ECG

• NORMAL
• May show AF or p mitrale if in sinus rhythm (indicates left atrial hypertrophy)

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)
• Pulmonary oedema

Echocardiography

• Performed every 6-12 months in moderate-severe MR
• Assess LV function and aetiology

Treadmill exercise test

Doppler echo to assess size and site of regurgitant jet

Cardiac catheterisation to confirm diagnosis, exclude other valve disease, assess CAD