Mitral Regurgitation

Question 1

4 vital parts for MV function. problems with any of these four part will lead to?

Answer 1

leaflets (need to overlap). chords to tether leaflets and prevent them from going into LA. papillary muscles/LV to pull the chords. annulus to confine leaflet area. failure of MV closing = MR

Question 2

how do problems with leaflet overlap cause MR?

Answer 2

decreased leaflet mobility (scars) = MR. normal mobility but hole in leaflets = MR. increased mobility so that they’re hypermobile and flail = MR

Question 3

2 broad types of MR

Answer 3

leaflets/chords abnormal = primary mitral valve problem. secondary MR is when leaflets/chords are normal but the LV is distorted so it pulls the valve apart (ex stretching annulus)

Question 4

MR caused by leaflet mobility decrease: most common cause?

Answer 4

rheumatic mitral valve: leaflets are scarred and fused so can’t close properly

Question 5

leaflet perforation: due to? almost always from?

Answer 5

leaflet destruction or degeneration: almost always from valve infection aka endocarditis

Question 6

MR: what happens when leaflet mobility increased too much?

Answer 6

leaflet and chords stretch, billow into left atrium and no more overlap of leaflets = MR, from prolapse of leaflet

Question 7

what is a flail leaflet? cause is always?

Answer 7

leaflet tip points into the LA. from rupture of chords.

Question 8

most common cause of severe MR is?

Answer 8

mitral valve prolapse. the leaflets are redundant and billow into the LA

Question 9

mitral valve prolapse: usually no? can be associated with? rarely will?

Answer 9

usually no symptoms, benign. can have chest pain and palpitations. rare: thrombi form on MV.

Question 10

what might you hear in MVP?

Answer 10

mid systolic click, from sudden tensing of the MV apparatus (earlier if standing bc more MR, later if lying/squatting bc less MR)

Question 11

MVP: what tests? treatment?

Answer 11

ECG/CXR usually normal. echo will show leaflet morphology and severity of prolapse/regurgitation. treatment usually not needed, but if severe you can repair or replace the MV

Question 12

in secondary valve problems: what is okay? what is the main problem?

Answer 12

leaflets and chords okay, main problem with with LV distortion or dysfunction

Question 13

example causes of secondary LV

Answer 13

ischemic paillary muscle. ischemic scarred LV. LV dilation that increases annulus size.

Question 14

ischemic papillary muscle in MR

Answer 14

secondary MR because muscle fails to pull on chords/leaflets so the leaflet prolapses and bilows in LA = MR. is very rare.

Question 15

“ischemic MR” is almost never? almost always due to?

Answer 15

almost never active ischemia anymore. almost always due to LV remodeling so it distorts papillary muscle position. (old ischemia leads to scar)

Question 16

top 3 common causes of MR

Answer 16

mitral valve prolapse syndrome (primary MV disease b/c of stretch chords/leaflets). secondary MR from a primary LV problem: LV dilation so annulus stretches. ischemic MR that causes LV scarring.

Question 17

if mitral valve is leaky, what happens to LA pressure? then what happens?

Answer 17

increased LA volume. increased diastolic MV flow, which increases LV filling = increased LV volume and pressure

Question 18

MR: LV needs to accommodate both ___ and ___ to do what?

Answer 18

both forward volume and volume of MR ejected backwards into LA = it needs twice the output to maintain normal forward flow

Question 19

the higher your BP (and thus LVP), what happens to MR?

Answer 19

increases MR: because LA is low pressure chamber, so it decreases LV afterload. aka it’s easier for blood to go to the LA than the higher pressure aorta

Question 20

acute MR: is what? no time for? so what?

Answer 20

acute severe illness when there is an acute injury to valve. no time for LA or LV to dilate = huge increase in LAP, so huge increase in pulmonary pressure = pulmonary edema, poor forward output (and so decreased BP)

Question 21

in acute MR, what happens to LV filling?

Answer 21

LA fills from both pulmonary veins and MR so that increases LV filling in diastole. that means more LV output and contractility