Mitral Stenosis
Definition
Narrowing of the mitral valve orifice impeding the diastolic flow of blood from the left atrium into the left ventricle
Etiology
- Rheumatic heart disease(most common)
- Severe mitral annular calcification
- Congenital (e.g., parachute mitral valve) - rare
- Left atrial myxoma - obstructs flow through mitral valve
Signs and Symptoms
- Dyspnea, orthopnea, paroxysmal nocturnal dyspnea
- Fatigue due to low cardiac output
- Chest pain due to RV ischemia in severe PAH
- Syncope
- Hemoptysis
- Ortner’s syndrome (hoarseness due to left atrium compressing left recurrent laryngeal nerve)
Complications
- Left atrial thrombus and systemic embolization leading to stroke
- Atrial fibrillation
- Decreased cardiac output
- Pulmonary hypertension and Right heart failure
- Pulmonary edema
- Infective endocarditis - very rare in isolated MS
Cardiac Auscultation
- Loud S1
- Opening snap
- Mid diastolic rumble with presystolic accentuation
- Loud P2 if patient has pulmonary hypertension
Electrocardiogram
- Left atrial enlargement
- Atrial fibrillation
- RVH secondary to PAH
Chest X-ray
- Left atrial enlargement
- Pulmonary venous hypertension, congestion and/or edema
- Main pulmonary artery enlargement
- Right ventricular enlargement and Right atrial enlargement in late cases
- Mitral valve calcification
Cardiac Catheterization
- Measures transmitral pressure gradient
- The gradient between left atrial pressure (or PAWP) and left ventricular diastolic pressure is calculated
- Determines mitral valve area by the Gorlin formula
MVA (cm2) = (CO ÷ DFP) ÷ (38.0 x MPG)
where MVA is the mitral valve area, CO is cardiac output, DFP is the diastolic flow period, 38.0 is the constant and MPG is pressure gradient.
Treatment
- Rheumatic prophylaxis with penicillin
- Digitalis, Diuretics, Rate reducing drugs, Anticoagulation
- Balloon mitral valvotomy (BMV)
- Commissurotomy (open or closed)
- Mitral valve replacement
M-Mode
- Thickened mitral valve leaflets
- Decreased E-F slope of the anterior mitral valve leaflet - Usually less than 30 mm/sec
- Anterior motion of the posterior mitral valve leaflet
- Decreased A wave of the mitral valve leaflet
- Reduced mitral valve leaflet excursion (D-E excursion)
- Abnormal septal wall motion (paradoxical or flat) due to right ventricular volume and/or pressure overload
- Left atrial enlargement
- Pulmonary hypertension
2-D
- Thickened mitral valve leaflets, especially at the leaflets and chordae
- Diastolic doming of the anterior mitral valve leaflet
- Left atrial enlargement
- Left atrial thrombus
- Unaffected left ventricle
- Right Ventricular and atrial enlargement
- Determine whether Lutembacher’s syndrome is present (look for ASD)
- Determine whether AS, TS, and/or PS (rare) is present
- Determine the anatomic mitral valve area by planimetry of the mitral orifice in the parasternal short-axis view of the mitral valve
- Evaluate mitral valve leaflet morphology for acceptability for BMV
PW and CW Doppler
- Turbulent flow
- Increased mitral valve E velocity recorded at the mitral valve leaflet tips (> 1.3 m/sec)
- Decreased E-F slope of the mitral inflow Doppler tracing (indicates an increased pressure half-time)
- Determine the pressure half-time
- Determine the mitral valve area by the pressure halftime method
- Determine the mitral valve area utilizing the continuity equation
- Determine the mean pressure gradient
- Determine the end-diastolic pressure gradient
- Determine the pulmonary artery pressures (SPAP, MPAP & PAEDP)
- Determine whether aortic stenosis, tricuspid stenosis, and/or pulmonic stenosis (rare) is present
- Determine the presence and severity of valvular regurgitation
Color Flow Doppler
- Flame shaped turbulent jet at mitral valve orifice which extends into the left ventricle in diastole
Go to Page 2 for assessment of MS severity and suitability for valvotomy