Today we discussed mitral stenosis. A few issues that came up about this big topic:
Predominant cause is rheumatic. Many pts with rheumatic heart disease have multiple valve lesions (25% have isolated MS; 40% have MS+MR; ~35% have aortic valve involvement)
Primary problem in MS is insufficient flow across the MV that leads to LA enlargement and high LA pressures to compensate. Remember that the pressure gradient for given valve area varies with square of flow (i.e. doubling flow requires 4x higher pressure gradient- this is also important in aortic stenosis).
Therefore, situations that increase flow (usually from tachycardia) cause dyspnea -
A-fib, infection, pregnancy, exercise are common ones
Tachycardia also decreases diastolic filling time, decreasing forward flow.
The high LA pressures needed to compensate for decreased diastolic filling time in tachycardia can lead to flash pulmonary edema. Atrial fibrillation is even worse because the atrial kick is relatively more important.
LA enlargement from elevated pressures predisposes to AF
Important complications of MS: pulmonary edema, atrial fibrillation, cardio-embolic stroke (from stasis and A-fib- very high risk of stroke in this setting), pulmonary HTN, endocarditis
Symptoms:
1) Dyspnea: most common, esp with exertion. Any situation causing increased flow across valve brings on (esp. tachycardia).
2) Hemoptysis: May occur from rupture of dilated bronchial veins
3) Chest pain: uncommon; often from secondary pulmonary HTN
4) Palpitations: A-fib
5) Other: Hoarseness (Ortner's sign for medical jeopardy fans), edema
Physical:
General- May see obvious resp distress, mitral facies (i.e. pink-purple patches from vasoconstriction on face)
Pulse: May see A-Fib. Usually normal, but may see low volume.
JVP: May see signs of pulmonary HTN as consequence of MS
Palpation: may have tapping S1 (pliable anterior leaflet). In LLD, may palpate diastolic thrill. May have RV heave and palpable P2 from pulm HTN.
Heart sounds:
Major findings are
1) loud S1 early, soft late in course
2) opening snap- early diastolic sound of MV opening; moves closer to S2 with more severe
3) diastolic rumble (murmur) post- opening snap
4) late diastolic murmur with presystolic accentuation from atrial kick
Others:
1) ECG- L atrial enlargement- 'p-mitrale'
2) CXR- splayed carina, double R heart border, flat or everted L heart border from LA enlargement
Link:
Click here for a nice website from the Cleveland Clinic summarizing MS
