week 4 Mitral Stenosis Flashcards
(42 cards)
Mitral Stenosis
restricted opening of MV leaflets during diastole
Mitral Annulus
D shaped ring that supports the leaflets
AMVL vs PMVL - shape
AMVL - shorter and wider; attaches to 1/3 of annulus
PMVL - longer and narrower; attaches to 2/3 of annulus
AMVL and PMVL have about the same area
Commissures
where the AMVL and PMVL meet
PM commissure and AL commissure
chordae tendineae
string like fibers that attach MV leaflets to paps
prevent prolapse of leaflets into LA during systole
NOT false tendons (false tendons do not attach to MV apparatus)
Pap muscles - which wall are they on and which coronary arteries supply them?
AL pap - Ant Lat wall - LAD and Cx
PM pap - Inferior wall - PDA (more likely to be damaged post MI)
Etiology of MS?
Congenital = rare, usually diagnosed in peds, often associated with other heart problems
- Annular hypoplasia
- Commissural fusion
- Parachute MV
Acquired
- Rheumatic*
- MAC
Causes of LVOT obstruction, which is hemodynamically similar to MS…
- MV endocarditis
- LA myxoma
- Cor-triatriatum
- supravalvular ring
What is the most common cause of MS?
Rheumatic (99%)
(and MAC is the 2nd most common)
Annular hypoplasia
A congenital cause of MS
under development of MV (severe MS)
Commissural fusion
A congenital cause of MS
MV opening is too small
Parachute MV
A congenital cause of MS
only a single pap muscle and all chordae go to it
Rheumatic MS
An acquired cause of MS - most common, severe
occurs many years after rheumatic fever from untreated strep throat
AMVL looks like hockey stick (diastolic doming of leaflets)
PMVL is thick / not moving
commissural fusion
thick leaflets and thick/short chordae
calcification (later in disease)
In what order does rheumatic fever damage valves?
- MV
- AoV
- TV
- PV - rare
MAC
An acquired cause of MS
elderly often have mild MAC, only causes MS if mod-severe MAC (and MS is usually less severe than MS caused by rheumatic)
Ca build up on valve; starts at annulus and with time builds out
What are the risk factors for MAC?
elderly (*usually just mild MAC in old ppl)
HT
diabetes
hypercalcemia
renal dialysis
marfans
Rheumatic vs MAC - how to tell them apart
Rheumatic - hockey shaped AMVL, uniform brightness and annulus is same brightness as leaflets
MAC - chunky brightness and annulus is brighter than leaflets
MV endocarditis
Can cause an LVOT inflow obstruction, but more likely to cause MR
vegetation (bacteria) growing on valve
usually patient has history of fever (post surgery) or IV drug use = exposed to bacteria
LA myxoma
Causes LVOT inflow obstruction
Primary tumor of the heart, benign but blocks inflow and risk of embolism. Need open heart surgery to remove
Looks like large ball in LA, attached by one point to IAS. Swings in and out of MV as it opens
Emergency - tell doctor before patient leaves
Cor-triatriatum
Causes LVOT inflow obstruction
Membrane across LA with one or more holes in it
Supravalvular ring
Causes LVOT inflow obstruction - rare
narrowing of LA right before MV (btw LAA and MV)
Cor-triatriatum vs supravalvular ring
Cor-triatriatum - membrane across LA, more superior
supravalvular ring - narrowing in LA, right before MV
Hemodynamic consequences of MS
MS = smaller MV opening in diastole
= incr LA press, which causes
- LA dilates = incr risk A-fib and thrombus formation
- As disease progresses… get Pulm HT = RV dilation and tricuspid annulus dilation = TR = high RAP, therefore blood gets stuck in body (causes incr jugular venous press, liver congestion, ascites, pedal edema)….right heart failure
Signs and symptoms of MS
Dyspnea (SOB) and decr exercise tolerance
if severe:
Dyspnea at rest
Pulm vein congestion
low CO
A fib
right heart failure / jugular venous distention
Ortner syndrome (recurrent laryngeal nerve paralysis)
