Mitral Stenosis

Underlying rheumatic heart disease in almost all patients (although history of rheumatic fever is often absent)

An opening snap following A₂ due to stiff mitral valve

Interval between opening snap and aortic closure sound is long when the left atrial pressure is low but shortens as left atrial pressure rises and approaches the aortic diastolic pressure

Low-pitched rumble at apex with patient in left lateral position, increased by brief exercise

Moderate stenosis (valve area 1.5–1.0 cm²): exertional dyspnea and fatigue common, especially with tachycardia

Severe stenosis (valve area < 1.0 cm²): severe pulmonary hypertension develops due to a "secondary stenosis" of the pulmonary vascular bed

Sudden increase in heart rate may precipitate pulmonary edema

Paroxysmal or chronic atrial fibrillation develops in ~50–80%, may precipitate dyspnea or pulmonary edema

ECG typically shows left atrial abnormality and, often, atrial fibrillation

Doppler echocardiography confirms diagnosis and quantifies severity by assigning 1–4 points to each of four observed parameters, with 1 being the least involvement and 4 the greatest

• Mitral leaflet thickening

• Mitral leaflet mobility

• Submitral scarring

• Commissural calcium

Cardiac catheterization to detect valve, coronary, or myocardial disease, usually done only after a decision to intervene has been made

Control heart rate

Attempt conversion of atrial fibrillation

Once atrial fibrillation occurs, provide lifelong anticoagulation with warfarin, even if sinus rhythm is restored

Intervention to relieve stenosis indicated for symptoms (eg, pulmonary edema, decline in exercise capacity) or evidence of pulmonary hypertension

Percutaneous balloon valvuloplasty

• Low mortality rate (< 0.5%)

• Low morbidity rate (3–5%)

• Can be repeated if the morphology of the valve remains suitable

• Not effective when bioprosthetic valve stenosis occurs

Surgical valve replacement is done in combined stenosis and regurgitation or when the mitral valve is significantly distorted and calcified

Operative mortality rate is ~1–3%