Mitral Regurgitation Flashcards
What causes mitral regurgitation?
Problems with MV parts (leaflet, chords, papillary muscle, annulus) will lead to failure of MV closing and cause MR
What problem can occur with leaflet overlap leading to MR?
decreased leaflet mobility = scarred, tied down
normal leaflet mobility = hole in leaflets
increased leaflet mobility = hypermobile / flail (ie. prolapse)
What are the two types of MR?
Leaflet / Chords abnormal = 1° mitral valve problem
LV distorted –> pulls mitral valve apart = 2° mitral regurgitation (leaflets / chords normal)
What is the most common cause of primary mitral valve problem?
Rheumatic mitral valve
What causes leaflet perforation?
Perforation due to leaflet destruction / degeneration
almost always from valve infection = endocarditis
What is another term for primary MR where there is increased leaflet mobility?
MV prolapse
What happens in MV prolapse?
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)
What is the most common cause of severe MR?
MVP
T or F: MVP show symptoms
F:
usually no symptoms, benign!
can be associated with vague chest pain / palpitations
sudden tensing of MV apparatus in mid-systole –> ‘click’
T or F: ECG and CXR are normal in MVP
T
What does echo show for MVP?
shows leaflet morphology, severity of prolapse + MR
What is the usual treatment for MVP?
usually none needed (NO endocarditis prophylaxis)
if severe MR develops –> consider MV repair
if MV irreparable –> replace MV
T or F: Ischemic papillary muscle is common
F: very rare
What happens in 2o MR involving ischemic papillary muscle?
Papillary muscle fails to ‘pull’ on chords / leaflet leaflet prolapses, billows into LA
What happens in 2o MR involving ischemic scarred LV?
Scarred papillary muscle (from old infarct) ‘pulls’ on chords / leaflet –> leaflet pulled open
What happens in 2o MR involving LV dilation?
Annulus dilates (usually because LV dilates) –> leaflet cannot cover area of annulus +pap. muscles move out of place
What are the top three common causes of MR?
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)
What is pathophysiological in MR?
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
T or F: Acute MR is a severe illness
T
What happens in acute MR?
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
What kind of heart sounds are heard in acute MR?
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
T or F: you can expect cardiogenic shock in MR
T
What are symptoms of cardiogenic shock?
BP may be very low
increased HR
apex non-displaced
lungs: severe edema –> +++ crackles
T or F: in chronic MR there is also a rise pressure in lungs
F:
Chronic illness –> LA & LV dilate (less stiff)
Compliant (stretchy) LA / LV –> no ↑↑↑ pressures into lungs until late in time course
What is the pathophysiology of chronic MR?
increased LV filling –> increased LV volume –> increased LV wall stress
–> compensatory increase in LV wall thickness
= lengthening & thickening of muscle fibers
= ‘ECCENTRIC’ LV HYPERTROPHY
T or F: in chronic MR the LV can accept more volume without increase in LVP
T: because had more time to become compliant
Without any further change to mitral valve, what would worsen chronic MR?
very high systLV Pressure
- high Aortic blood pressure - narrowed aortic valve (aortic stenosis)
How does chronic MR leads to worsened MR?
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
What happens as a result of reduced LV function in chronic MR?
--> decompensation
decreased forward output
fatigue
AND
increased back- pressures
increased LAP
increased pulmonary P’s
--> systolic heart failureHow does chronic MR lead to conduction issues?
Long-standing drastically increases LA volume –> pulls wiring apart
- -> risk of atrial fibrillation (short circuits) - -> risk of blood clots + increased LAP --> systolic heart failure
What may happen as a result of increased LAP in chronic MR?
Long-standing increased pulmonary venous pressures
- pulmonary hypertension - right ventricular failure / dilation - peripheral edema, low forward output
What are some early symptoms of chronic MR?
Symptoms of increased backward pressure: LEFT HEART FAILURE dyspnea orthopnea paroxysmal nocturnal dyspnea
What are some later symptoms of chronic MR?
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)
What kind of heart sounds would be in chronic MR?
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’
What phys findings would be associated with chronic MR?
BP , HR normal
lungs: clear
LV apex enlarged, displaced, diffuse, hyperdynamic
palpable MR ‘thrill’
What is a holosystolic murmur?
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)
What would one see in decompensated chronic MR?
BP maybe low
lungs: decreased edema ?
RV enlarged –> RV ‘heave’ , increased JVP, pulsating tender liver
What may show in ECG for chronic MR?
may show LVH, LA enlargement
may show atrial fibrillation
What may show in CXR for chronic MR?
enlarged LV, LA
may show prominent pulmonary veins
if decompensated –> pulmonary edema
–> RV enlarges
What may show in echo for chronic MR?
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
What may show in cath for chronic MR?
can (crudely) estimate severity of MR
can assess LV function and pressures
only way to assess coronaries before surgery
How to prevent MR?
- NO Antibiotics before dental work (NO more endocarditis prophylaxis)
- Maintain good dental hygiene (reduce risk infective endocarditis)
- Careful follow-up of asymptomatic patients with MR, counselling about main symptoms
- Regular echo exams to assess for LV size & function
What is treatment of MR?
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
T or F: dysfunctional LV’s tend to get WORSE after valve replacement
T because no longer can empty into low pressure LA, have to pump entirely into high pressure aorta
Does a MV repair or replacement have better outcomes?
MV repair –> better outcomes than replacement
When to have surgery (ie. replacement) for MR?
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
