Track 7: Mitral Regurgitation Flashcards
First key feature to differentiate in MR
Primary: Disease of the valve leaflets
Secondary: Disease of the LV, LV dysfunction (ie dilated or ischemic CMP), pathophysiology is primarily LV systolic dysfunction
Describe the hemodynamics that occur during MR
At the time of mitral valve closure there will be blood back flow back into the left atrium culminating in what is known as a large D wave
Large D wave causes elevation of LV pressure and LA pressure
Number of blood velocities that go from LV to LA
In severe MR what extra component might you hear on auscultation
Early diastolic rumble (large amount of blood going from LA to LV, so diastolic filling sound might be present)
MR effect on left atrium and left ventricle
Blood back into LA causes LA dilatation, increase in LA pressure
Regurgitant blood back into LV, LV dilatation, increase in LV pressure
***Increase in LA and LV pressures
Name the 2 important pathophysiologic concepts in regards to symptoms associated with MR
Increased LA pressure
- DOE
- PND
- Orthopnea
- Fatigue
Name the 2 key underlying consequences we need to be aware of in MR
- Increased left atrial pressure
- Long standing volume overload at LV leading to LV systolic dysfunction over time
Loud holosystolic murmur heard best at the apex heard best with bell
Early diastolic filling sound (caused by)?
MR
High pressures in the LA, blood going from LA to LV in diastole
Key features in MR
- DOE
- Fatigue
What is the main endpoint that occurs with primary MR
Long standing volume overload of the left ventricle will eventually lead to irreversible LV systolic dysfunction, very poor prognosis once this is reached
The prognosis of primary MR becomes very poor (even if intervention ultimately performed) when what occurs?
LV sytolic dysfunction
Briefly describe the natural history of MR and why this matters
- Patients can remain asx for many years and even decades when MR is in the mild-moderate range
- Once they reach the severe range, steady decline will ensue
- Long standing volume overload does have some impact on myocardium
- LV dysfunction develops (EF < 60% develops)
- Sxs often don’t arise until the severe range (DOE, fatigue being the main)
- Once EF depressed and sxs present, poorer prognosis
Besides severity of MR itself, what is the other key echocardiographic feature that needs to be monitored?
EF
(specifically looking for EF < 60%)
What constitutes a reduced EF in patient with MR?
< 60%
In MR there is a low impedence LA which the ventricle will eject into, so the EF is actually erroneously higher
(ie SV = end diastolic volume - end systolic volume, EF = SV/EDV x 100)
So you have blood ejecting into aorta but also blood leaving the ventricle back into the LA, EF erroneously high blood still leaving LV but not all in the right direction
(normal patients can have EF >50% and be normal)
***Double check you understand this concept correclty
Besides EF, what is another echocardiographic value to assess MR
end systolic dimension (ESD), > 40 mm
As volume overload effects the LV, the ventricle will get larger and larger
What end systolic dimension are you looking for in MR
> 40 mm
Indicates LV dysfunction has occurred
