Cardiac Valve Defects - Mitral Regurgitation

Question 1

Aetiology of Mitral Regurgitation (3).

Answer 1

1. Defects in Mitral Annulus (Valve Ring) = Secondary/Functional MR.
2. Defects in Cusps.
3. Defects in Papillary Muscles.

Question 2

What defects in the mitral annulus cause mitral regurgitation?

Answer 2

LV Dilation (any cause of LV failure) causes secondary stretching of the valve ring so the valve cannot close properly.

Question 3

What defects in the cusps cause mitral regurgitation?

Answer 3

1. Mitral Valve Prolapse.
2. Infective Endocarditis.
3. Post-Rheumatic Fever.

Question 4

What defects in the papillary muscles cause mitral regurgitation?

Answer 4

1. Post-MI Rupture.

2. Ischaemia due to Coronary Artery Atheroma.

Question 5

Nature of Mitral Regurgitation Murmur.

Answer 5

1. Pan-Systolic.
2. High-Pitched.
3. Whistling Murmur.
4. Radiates to Left Axilla.
5. Best at the Apex.

Question 6

ECG Finding in Mitral Regurgitation Murmur.

Answer 6

1. Broad P Wave (Atrial Enlargement).
2. Left Ventricular Hypertrophy.
3. Left Axis Deviation.

Question 7

Aetiology of Acute Mitral Regurgitation.

Answer 7

1. Infective Endocarditis.

2. Rupture of Papillary Muscle after MI.

Question 8

Complication of Acute Mitral Regurgitation.

Answer 8

1. Blood flows back into the LA.
2. Increased pressure in LA.
3. Increased pressure in the pulmonary circulation.
4. Transudation of Fluid = Pulmonary Oedema (Acute Left Heart Failure).

Question 9

Management of Acute Mitral Regurgitation.

Answer 9

1. Medical : Nitrates, Diuretics, Positive Inotropes, Intra-Aortic Balloon Pump (Increase CO).
2. Severe = Surgery.

Question 10

Aetiology of Chronic Mitral Regurgitation (4).

Answer 10

1. Dilation of Mitral Annulus.
2. Mitral Valve Prolapse.
3. Post-Rheumatic Fever.
4. Papillary Muscle Ischaemia.

Question 11

Complication of Chronic Mitral Regurgitation (4).

Answer 11

1. Blood flows back into the LA.
2. Asymptomatic Period of Compensatory Changes = LA Dilation without Substantial Increase in LA Pressure.
3. LV Hypertrophy.
4. Decompensation = Progressive LV Failure.

Question 12

Surgical Management in Mitral Regurgitation (3).

Answer 12

1. Mitral Valvuloplasty - Valve Repair (best).
2. Mitral - Mechanical Valve Replacement (long-lasting but lifelong anticoagulation).
3. Mitral - Bioprosthetic Valve Replacement (limited durability but no anticoagulation).

Question 13

Pathophysiology of Mitral Valve Prolapse (2).

Answer 13

1. Normal Dense Collagen and Elastin Matrix of Valve is replaced with loose myxomatous connective tissue-containing abundant glycosaminoglycans.
2. The leaflets becomes so enlarged that one of the leaflet prolapses back into the LA during systole.

Question 14

Sounds in Mitral Valve Prolapse.

Answer 14

Non-Ejection Click, Variable in Timing (Snapping of Mitral Chordae during Systole).

Question 15

Investigations of Mitral Valve Prolapse.

Answer 15

Echocardiogram : >2mm above Annular Plane.