Mitral regurgitation

Question 1

What is mitral regurgitation?

Answer 1

retrograde flow of blood from LV to LA during systole
aka mitral insufficiency

Question 2

How can MR be classified based on aetiology?

Answer 2

Primary: direct involvement of valve leaflets or chordae tendinae
Secondary: changes of LV lead to valvular incompetence

Question 3

How can MR be classified according to onset?

Answer 3

Acute: Acute dysfunction of MV leads to volume overload + Sx of acute heart failure.

Chronic: Occurs over many years, results in volume overload + LV dysfunction

Question 4

Describe the pathophysiology of acute MR

Answer 4

↑ LA volume with normal LA compliance + ↑ LV end-diastolic volume
→ rapid ↑ in LA + pulmonary pressures
→ pulmonary venous congestion
→ pulmonary edema

Question 5

Describe pathophysiology of decompensated chronic MR

Answer 5

Progressive LV enlargement + myocardial dysfunction
→ ↓ stroke volume
→ ↑ end-systolic + end-diastolic volume
→ ↑ LV + LA pressure
→ pulmonary congestion, possible acute pulmonary edema, pulmonary HTN, + RH strain

Question 6

Name 2 conditions associated with MR

Answer 6

Ehlers-Danlos syndrome
Marfan syndrome

Question 7

List 4 primary causes of MR

Answer 7

Degenerative mitral valve disease e.g. mitral valve prolapse (most common)
Rheumatic heart disease
Infective endocarditis: vegetations prevent valve closure
Ischemic MR: papillary muscle rupture following acute MI

Question 8

Give 2 secondary causes of MR

Answer 8

Coronary artery disease or prior MI causing papillary muscle involvement
Dilated cardiomyopathy + left-sided HF

Question 9

Describe symptoms in MR

Answer 9

Most asymptomatic,
Mild to mod MR may stay largely asymptomatic indefinitely.
Sx tend to be due to LV failure, arrhythmias or pulmonary HTN.

Question 10

List 4 symptoms of MR

Answer 10

Dyspnoea
Fatigue
Pedal oedema
Palpitations (new onset AF common)

Question 11

List 4 signs of MR

Answer 11

Pansystolic murmur that radiates to axilla (highpitched, blowing)
Laterally displaced, thrusting apex beat
Soft S1 (due to incomplete closure of valve)
S3 (if LV dysfunction)

Question 12

List 3 signs of mitral valve prolapse

Answer 12

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

Question 13

What does an ECG look like in MR?

Answer 13

Acute: Normal/ sinus tachy/ AF
Chronic: broad p wave +/- p mitrale (atrial enlargement), AF

Question 14

Describe the CXR findings in chronic MR

Answer 14

Decompensated MR + acute MR: signs of pulmonary congestion
Chronic: LA enlargement, Cardiomegaly (due to LV dilation)

Question 15

What investigation is diagnostic of MR?

Answer 15

TTE
Allows assessment of LV ejection fraction + end-systolic dimension

Question 16

Describe management of acute MR

Answer 16

Emergency surgery: repair/ replacement
Whilst awaiting surgery, manage Sx of HF

Question 17

Describe management of acute MR prior to surgery

Answer 17

Furosemide: for pulmonary oedema
Nitroprusside: reduces MR by reducing systemic vascular resistance
Intraaortic balloon counterpulsation: to increase CO

Question 18

Describe management of asymptomatic chronic MR

Answer 18

LVEF >60%: watchful waiting
LVEF <60%: repair/ replacement

Question 19

Describe management of symptomatic chronic MR

Answer 19

Repair/ replacement
If high surgical risk: transcatheter mitral valve intervention
HF Mx to optimise cardiac function: diuretics, ACEi + BB

Question 20

Which surgical intervention is preferred in MR?

Answer 20

Evidence for REPAIR over replacement is strong in degenerative regurgitation
Lower mortality + complications