Mitral Stenosis

Question 1

What is the cause of the mitral stenosis?

Answer 1

Almost invariably due to prior rheumatic fever

Mitral stenosis is the most common chronic valvular lesion with rheumatic fever

Question 2

What is rheumatic fever?

Answer 2

Auto-immune reaction to Group A Streptococci infection of pharynx

Question 3

What does RF affect?

Answer 3

affects heart (all cardiac tissues), skin, joints, and brain

Question 4

What damage does RF do?

Answer 4

most important damage: heart valves (scarring) –> valve stenosis + / or regurgitation years later

Question 5

To prevent recurrent RF?

Answer 5

chronic Penicillin

Question 6

What is the next common target after mitral valve in RF?

Answer 6

aortic valve

Question 7

What is the criteria used for diagnosis of ARF?

Answer 7

Jones Criteria

Question 8

What is Jones criteria?

Answer 8

requires:
evidence of recent Group A Strep infection
AND
2 MAJOR diagnostic criteria,
OR
1 MAJOR and 2 Minor diagnostic criteria

Question 9

What are signs of recent GAS infection?

Answer 9

throat swab culture growing Strep. A bacteria

Antibodies to Strep. toxin (Anti-Streptolysin O Titer = ASOT)

recent scarlet fever (well defined
severe Strep. throat infection plus
with rash)

Question 10

What are Jones’ major criteria?

Answer 10

carditis (all layers of heart)
migrating joint inflammations (polyarthritis)

rash (moving, red, central clearing=erythema marginatum)

skin nodules (subcutaneous)

chorea (involuntary smooth limb movements= ‘St. Vitus’ dance’)

Question 11

What are Jones’ Minor Criteria?

Answer 11

fever
blood tests showing inflammation (e.g. increased white blood cell count, high Erythrocyte sedimentation rate [ESR])
arthralgias (joint pains, but NO inflammation)
increased PR interval on ECG

Question 12

What symptoms would you expect early on after developing major mitral stenosis and why?

Answer 12

Dyspnea because:

Increased LA pressure

	- -> increased pulmonary venous + capillary pressures 
	- -> increased pressure driving fluid into lungs
	- -> increased stiffness of lungs and work of breathing

Question 13

In mitral stenosis when would dyspnea more prominent?

Answer 13

In periods of increased heart rate (shorter diastole)

or in increased flow states (exercise/anemia/fever…)

Question 14

What kind of dyspneas can occur in MS?

Answer 14

ORTHOPNEA
and
PAROXYSMAL NOCTURNAL DYSPNEA

Question 15

What is orthopnea?

Answer 15

Dyspnea upon lying flat due to:

• -> immediate increase in venous return from blood pooled in lower extremities
  
  • -> increased flow across MV –> dyspnea

Question 16

What is paroxysmal nocturnal dyspnea?

Answer 16

Sudden dyspnea after lying flat for hours due to:

slow reabsorption of tissue fluid–> increased venous return –> sudden dyspnea awakens

Question 17

Why does hemotypsis occur in MS?

Answer 17

increased LA pressure –>
increased pulmonary venous pressure
–> fragile bronchial vein connections with pulmonary veins
–> increased chance rupture of bronchial veins

		-->  Bleed into lungs ( hemoptysis)

Question 18

Why does fatigue occur in MS?

Answer 18

–> increased LA pressure leads to:
increased pulmonary venous pressure
increased pulmonary artery pressure
–>pulmonary artery intimal scarring
–> increased pulmonary artery pressure
–> Right Ventricular pressure
–> RV dilation and failure
–> insufficient forward output
↓pulmonary congestion /edema/dyspnea + FATIGUE / Edema / Ascites (backpressure)

Question 19

Why does MS lead to arrythmias?

Answer 19

–> LA pressure –> increased LA enlargement
increased likelihood LA ‘short circuits’
–> chaotic atrial rhythm = atrial FIBRILLATION

Question 20

What is atrial fibrilation?

Answer 20

• -> no organized atrial contraction, atria ‘jiggle’
  - sluggish flow, blood clots, and EMBOLI (esp @ LA appendage –> stroke)
• -> loss of ‘atrial kick’
  - insufficient forward output
  - Sudden increase in DYSPNEA / FATIGUE
• -> leads to increase of HR
  - less time in diastole, so less volume goes through MS
  - sudden dyspnea/fatigue

Question 21

T or F: any long-standing left heart valve disease and any heart failure type can increase risk of atrial fibrillation

Answer 21

T

Question 22

What is the most common cause of aFib in NA?

Answer 22

in N. America, most common causes = age + hypertension –> ‘stiff’ LV –> ↑LA pressure –> LA enlargement –> Afib risk

Question 23

T or F: most aFib patients need HR control meds

Answer 23

T

Question 24

What kind of heart sounds are felt in MS?

Answer 24

Loud S1:
thickened leaflets / chords –> generate louder sound (even palpable)
when rigid, calcified, S1 intensity gradually lower

Opening Snap:
sound from MV opening (counterpart to loud S1)
also disappears once valve becomes rigid, severely calcified

Question 25

What kind of sound can be heard during diastole?

Answer 25

MV turbulent flow–> murmur:
low-pitched ‘rumble’
in normal rhythm, atrial kick –> increased intensity = ‘pre-systolic accentuation’
the worse the MS, the longer into diastole the murmur lasts (longer time for pressure gradient to disappear)

Question 26

T or F: MS can sometimes lead to RV overload

Answer 26

T: happens later in the course

Question 27

What happens in RV overload?

Answer 27

enlarged, hypertrophied RV causes palpable lift underneath sternum = ‘parasternal lift’ or ‘RV heave’

right-sided S3 / S4 (abnormal RV diastolic function)

dilated RV –> stretches tricuspid annulus –> leaky tricuspid valve = tricuspid regurgitation

Question 28

What kind of tests would be ordered if MS is suspected?

Answer 28

• ECG
• CXR
• echocardiography
• cardiac catherization

Question 29

What kind of info can ECG give for MS?

Answer 29

enlarged LA
RV hypertrophy
Atrial fibrillation

Question 30

What kind of info can CXR give for MS?

Answer 30

calcified MV, enlarged LA
pulmonary venous engorgement
pulmonary interstitial edema (‘Kerley B lines’)
pulmonary alveolar edema (if severe)
(late) RV enlargement, enlarged Pulm. arteries

Question 31

What kind of info can Echo give for MS?

Answer 31

actually see the valve ‘in action’
assess severity of MS
assess pressure gradient across MV
assess other valves, as well as LV / RV function

Question 32

What kind of info can cath give for MS?

Answer 32

tubes inserted into right / left heart / aorta / PA
able to measure pressures and flows directly
check for coronary disease if needing surgery

Question 33

How to prevent MS?

Answer 33

Preventing rheumatic fever:
early treatment of Group A Strep pharyngitis

Preventing recurrences of rheumatic fever:
monthly intra-muscular Penicillin shots (till age 40, or 10 years after last attack)

Endocarditis prophylaxis—NO!:
NO antibiotics prior to dental cleaning

Question 34

How to medically treat MS?

Answer 34

Diuretics:
decrease volume load on LA / lungs / RV

Rate-slowing drugs (especially in Afib):
slower heart rate –> increase diastole to empty LA
–> beta-blockers, (digoxin), some calcium channel blockers (Verapamil, Diltiazem)

Anticoagulant (Coumadin = Warfarin):
if Afib (>20% annual stroke / embolic rate)
if severe MS, prior emboli, or severe heart failure

Question 35

What treatment would be good for MS to delay surgical replacement?

Answer 35

Balloon Valvuloplasty

Useful if MV still relatively pliable, not too severely calcified

Commissurotomy
now done ‘open-heart’ with cardio-pulmonary bypass machine, LA opened and surgeon cuts open MV commissures under direct vision
–> re-establishes two flaps

Question 36

What are indication for valve replacement?

Answer 36

Valve replacement if major symptoms, valves not suitable for balloon / surgical repair

Question 37

T or F: both types of valves require coumadin

Answer 37

F:
tissue–> lifelong antiplatelet
mech –> coumadin + aspirin