Cardio - Mitral Regurgitation

Question 1

suggest possible risk factors for MR

Answer 1

• female gender
• low BMI
• increasing age
• prior MI
• prior mitral stenosis or mitral valve prolapse

Question 2

what is the difference between primary and secondary MR?

Answer 2

Primary = intrinsic lesions affect 1 or several components of the MV.

Secondary (functional) = valve leaflets and chordae are structurally normal but MR results from distortion of subvalvular apparatus, secondary to LV enlargement and remodelling.

Question 3

name examples of acute MR causes

Answer 3

1. rheumatic fever (early presentation)
2. infective endocarditis
3. papillary muscle rupture (post-MI)
4. chordal rupture/leaflet flail (MVP, IE)

Question 4

name examples of chronic primary MR causes

Answer 4

1. myxomatous degeneration and MVP (most common)
2. MVP secondary to Marfan or Ehler’s Danlos syndrome
3. mitral annulae calcification
4. congenital heart disease (leaflet cleft, AV canal)
5. HOCM with SAM

Question 5

name examples of chronic secondary MR causes

Answer 5

1. post-MI LV remodelling
2. dilated cardiomyopathy (ischaemic or non-ischaemic)

Abnormal dilated LV causes papillary muscle displacement… leaflet tethering with associated annular dilation… prevents coaptation.

Question 6

describe the pathophysiology and presentation of chronic MR

Answer 6

1. Compensated MR: increased volume in LA causes eccentric hypertrophy of LV to maintain normal pressures/stroke volume
2. decompensated MR: decreased LV stroke volume (unclear why)… LV dysfunction and LV dilation… way worsen MR.

Causes symptoms and signs of HF.

Question 7

describe the pathophysiology and presentation of acute MR

Answer 7

Regurgitant volume causes a volume and pressure overload of the LV and LA - increased pressure causes backup of blood in pulmonary system… pulmonary oedema.

Severe symptoms: dyspnoea, orthopnoea, PND +/- cardiovascular collapse and shock

Question 8

which Ix would you perform on someone with suspected MR?

Answer 8

1. Echo: to confirm Dx and assess severity (grade defined by regurgitant jet into LA).
2. ECG: may show broad P wave of LA enlargement.
3. CXR: may show LA and LV enlargement.

Question 9

how are most MR pts managed?

Answer 9

Valve repair (the sooner the better as prognosis worsens once pts become symptomatic).

Question 10

suggest possible complications of MR

Answer 10

1. pulmonary HTN
2. LV dysfunction of HF
3. AF +/.- thrombolic events