Mitral Regurgitation

Question 1

What causes mitral regurgitation?

Answer 1

Problems with MV parts (leaflet, chords, papillary muscle, annulus) will lead to failure of MV closing and cause MR

Question 2

What problem can occur with leaflet overlap leading to MR?

Answer 2

decreased leaflet mobility = scarred, tied down

normal leaflet mobility = hole in leaflets

increased leaflet mobility = hypermobile / flail (ie. prolapse)

Question 3

What are the two types of MR?

Answer 3

Leaflet / Chords abnormal = 1° mitral valve problem

LV distorted –> pulls mitral valve apart = 2° mitral regurgitation (leaflets / chords normal)

Question 4

What is the most common cause of primary mitral valve problem?

Answer 4

Rheumatic mitral valve

Question 5

What causes leaflet perforation?

Answer 5

Perforation due to leaflet destruction / degeneration

almost always from valve infection = endocarditis

Question 6

What is another term for primary MR where there is increased leaflet mobility?

Answer 6

MV prolapse

Question 7

What happens in MV prolapse?

Answer 7

Leaflet + chords stretch, billow into LA –> leaflet margins fail to coapt –> MR

OR

Flail leaflet = leaflet tip points into LA –> always has to be rupture of chords
(ie. still primary MV problem)

Question 8

What is the most common cause of severe MR?

Answer 8

MVP

Question 9

T or F: MVP show symptoms

Answer 9

F:
usually no symptoms, benign!
can be associated with vague chest pain / palpitations
sudden tensing of MV apparatus in mid-systole –> ‘click’

Question 10

T or F: ECG and CXR are normal in MVP

Answer 10

T

Question 11

What does echo show for MVP?

Answer 11

shows leaflet morphology, severity of prolapse + MR

Question 12

What is the usual treatment for MVP?

Answer 12

usually none needed (NO endocarditis prophylaxis)
if severe MR develops –> consider MV repair
if MV irreparable –> replace MV

Question 13

T or F: Ischemic papillary muscle is common

Answer 13

F: very rare

Question 14

What happens in 2o MR involving ischemic papillary muscle?

Answer 14

Papillary muscle fails to ‘pull’ on chords / leaflet leaflet prolapses, billows into LA

Question 15

What happens in 2o MR involving ischemic scarred LV?

Answer 15

Scarred papillary muscle (from old infarct) ‘pulls’ on chords / leaflet –> leaflet pulled open

Question 16

What happens in 2o MR involving LV dilation?

Answer 16

Annulus dilates (usually because LV dilates) –> leaflet cannot cover area of annulus +pap. muscles move out of place

Question 17

What are the top three common causes of MR?

Answer 17

Mitral valve prolapse syndrome = 1° MV disease
‘stretchy’ chords +leaflets (‘floppy valve’)
2° MR = 1° LV problem:
‘Ischemic’ MR = LV scar (old infarct) / (almost never true ischemia of papillary muscle)
Functional = LV dilates –> annulus stretches (from ischemic or non-ischemic LV dilation / dysfunction)

Question 18

What is pathophysiological in MR?

Answer 18

Increased LA volume leads to:

• increased diastolic MV flow
• increased LV filling
• increased LVP +/or LV volume

LV needs to accommodate both forward volume + volume of MR ejected backwards into LA
–> so need 2x ↑LV Output to maintain normal forward flow

LV contracts –> LVP > LAP –> lead to MR into LA because less afterload
–> more pressure builds up (LVP and BP) –> more MR

Question 19

T or F: Acute MR is a severe illness

Answer 19

T

Question 20

What happens in acute MR?

Answer 20

No time for LA or LV to dilate (still ‘stiff’)
MR –> but stiff LA –> very high LAP –> very high pulmonary P’s –> severe pulmonary edema +/- poor forward output –> low BP

LA fills both from pulmonary veins and MR –> increased LV filling in diastole
–> increased LV filling in diastole –> increases potential LV output/contractility BUT LV stiffness limits amount of LV volume

Question 21

What kind of heart sounds are heard in acute MR?

Answer 21

S1 / S2 maybe normal
S3 = sound from loaded LV filling early in diastole
S4 = sound from stiff LV filling late in diastole
murmur = from turbulent LV to LA flow—tapers off

Question 22

T or F: you can expect cardiogenic shock in MR

Answer 22

T

Question 23

What are symptoms of cardiogenic shock?

Answer 23

BP may be very low
increased HR
apex non-displaced
lungs: severe edema –> +++ crackles

Question 24

T or F: in chronic MR there is also a rise pressure in lungs

Answer 24

F:
Chronic illness –> LA & LV dilate (less stiff)
Compliant (stretchy) LA / LV –> no ↑↑↑ pressures into lungs until late in time course

Question 25

What is the pathophysiology of chronic MR?

Answer 25

increased LV filling --> increased LV volume --> increased LV wall stress --> compensatory increase in LV wall thickness = lengthening & thickening of muscle fibers = ‘ECCENTRIC’ LV HYPERTROPHY

Question 26

T or F: in chronic MR the LV can accept more volume without increase in LVP

Answer 26

T: because had more time to become compliant

Question 27

Without any further change to mitral valve, what would worsen chronic MR?

Answer 27

very high systLV Pressure - high Aortic blood pressure - narrowed aortic valve (aortic stenosis)

Question 28

How does chronic MR leads to worsened MR?

Answer 28

Longterm increased LV volume --> gradual, insidious decrease in LV systolic function AND Both increase LV size + reduced LV function --> increased annulus dilation / papillary muscle stretch --> increased MR

Question 29

What happens as a result of reduced LV function in chronic MR?

Answer 29

``` --> decompensation decreased forward output fatigue AND increased back- pressures increased LAP increased pulmonary P’s --> systolic heart failure ```

Question 30

How does chronic MR lead to conduction issues?

Answer 30

Long-standing drastically increases LA volume --> pulls wiring apart - -> risk of atrial fibrillation (short circuits) - -> risk of blood clots + increased LAP --> systolic heart failure

Question 31

What may happen as a result of increased LAP in chronic MR?

Answer 31

Long-standing increased pulmonary venous pressures - pulmonary hypertension - right ventricular failure / dilation - peripheral edema, low forward output

Question 32

What are some early symptoms of chronic MR?

Answer 32

``` Symptoms of increased backward pressure: LEFT HEART FAILURE dyspnea orthopnea paroxysmal nocturnal dyspnea ```

Question 33

What are some later symptoms of chronic MR?

Answer 33

Symptoms of long-standing ↑↑LA back-pressure: atrial fibrillation --> increased palpitations +/or clots / emboli RIGHT HEART FAILURE (late) peripheral edema + ascites, liver pain from venous backpressure (decreased forward RV output, increased fatigue, weakness, +decreased dyspnea)

Question 34

What kind of heart sounds would be in chronic MR?

Answer 34

S1 variable, S2 early S3: LV volume load pansystolic (ie. holosystolic) murmur from turbulent MR flow, lasts through all of systole diastolic murmur from torrential flow across MV in diastole = ‘flow rumble’

Question 35

What phys findings would be associated with chronic MR?

Answer 35

BP , HR normal lungs: clear LV apex enlarged, displaced, diffuse, hyperdynamic palpable MR ‘thrill’

Question 36

What is a holosystolic murmur?

Answer 36

High-pitched (high pressure gradient) Usually loudest at mitral area / apex Radiates widely, but usually into axilla (usual central or posterior jet of MR) tends to remain same intensity even if heart rate variability (unlike Aortic stenosis)

Question 37

What would one see in decompensated chronic MR?

Answer 37

BP maybe low lungs: decreased edema ? RV enlarged --> RV ‘heave’ , increased JVP, pulsating tender liver

Question 38

What may show in ECG for chronic MR?

Answer 38

may show LVH, LA enlargement | may show atrial fibrillation

Question 39

What may show in CXR for chronic MR?

Answer 39

enlarged LV, LA may show prominent pulmonary veins if decompensated --> pulmonary edema --> RV enlarges

Question 40

What may show in echo for chronic MR?

Answer 40

can define leaflet, chord, annulus morphology can assess severity of MR (+ other valve lesions) can assess LA size, LV size, LV function ***test of choice to assess MR***

Question 41

What may show in cath for chronic MR?

Answer 41

can (crudely) estimate severity of MR can assess LV function and pressures only way to assess coronaries before surgery

Question 42

How to prevent MR?

Answer 42

1. NO Antibiotics before dental work (NO more endocarditis prophylaxis) 2. Maintain good dental hygiene (reduce risk infective endocarditis) 3. Careful follow-up of asymptomatic patients with MR, counselling about main symptoms 4. Regular echo exams to assess for LV size & function

Question 43

What is treatment of MR?

Answer 43

lower BP --> decrease LV pressure --> decrease mitral regurgitation Useful in acute MR No proven benefit to BP lowering drugs (e.g. ACE inhibitors) if no hypertension in chronic MR (high BP would worsen MR) Diuretics and nitrates (ie. venous dilator): may help alleviate heart failure symptoms from excessive volume loading Rate-slowing drugs: if go into atrial fibrillation, best to prevent excessive tachycardia (+ need anticoagulant) Anti-arrhythmic and rate-slowing drugs: may help keep patient in normal rhythm (not routinely used), but need HR slowing

Question 44

T or F: dysfunctional LV’s tend to get WORSE after valve replacement

Answer 44

T because no longer can empty into low pressure LA, have to pump entirely into high pressure aorta

Question 45

Does a MV repair or replacement have better outcomes?

Answer 45

MV repair --> better outcomes than replacement

Question 46

When to have surgery (ie. replacement) for MR?

Answer 46

BP lowering drugs unproven to slow progression or delay need for surgery Surgery if major symptoms OR if LV shows asymptomatic decrease in function / increase in size