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INTRODUCTION

MITRAL STENOSIS (MS)

Etiology

Most commonly rheumatic, although history of acute rheumatic fever is now uncommon; congenital MS is rare cause, observed primarily in infants.

History

Symptoms most commonly begin in the fourth decade, but MS often causes severe disability at earlier ages in developing nations. Principal symptoms are dyspnea and pulmonary edema precipitated by exertion, excitement, fever, anemia, paroxysmal tachycardia, pregnancy, sexual intercourse, etc.

Physical Examination

Right ventricular lift; palpable S1; opening snap (OS) follows A2 by 0.06–0.12 s; OS–A2 interval inversely proportional to severity of obstruction. Diastolic rumbling murmur with presystolic accentuation in sinus rhythm. Duration of murmur correlates with severity of obstruction.

Complications

Hemoptysis, pulmonary embolism, pulmonary infection, systemic embolization; endocarditis is uncommon in pure MS.

Laboratory ECG

Typically shows atrial fibrillation (AF) or left atrial (LA) enlargement when sinus rhythm is present. Right-axis deviation and RV hypertrophy in the presence of pulmonary hypertension.

CXR

Shows LA and RV enlargement and Kerley B lines.

Echocardiogram

Most useful noninvasive test; shows inadequate separation, calcification and thickening of valve leaflets and subvalvular apparatus, and LA enlargement. Doppler flow recordings provide estimation of transvalvular gradient, mitral valve area, and degree of pulmonary hypertension (Chap. 121).

TREATMENT Mitral Stenosis

At-risk pts should receive prophylaxis for recurrent rheumatic fever (penicillin V 250–500 mg PO bid or benzathine penicillin G 1–2 M units IM monthly) (See Fig. 123-1). In the presence of dyspnea, sodium restriction and oral diuretic therapy; beta blockers, digitalis, or rate-limiting calcium channel antagonists (i.e., verapamil or diltiazem) to slow ventricular rate in AF. Warfarin (with target INR 2.0–3.0) for pts with AF and/or history of systemic and pulmonic emboli. For AF of recent onset, consider reversion (chemical or electrical) to sinus rhythm, ideally after ≥3 weeks of anticoagulation. Mitral valvotomy in the presence of symptoms and mitral orifice ≤ ~1.5 cm2. In uncomplicated MS, percutaneous balloon valvuloplasty is the procedure of choice; if not feasible, then open surgical valvotomy (Fig. 123-1).

FIGURE 123-1

Management of mitral stenosis (MS). There is controversy as to whether pts with severe MS (MVA <1.0 cm2) and severe pulmonary hypertension (PH) (PASP >60 mmHg) should undergo percutaneous mitral balloon valvotomy (PMBV) or mitral valve replacement (MVR) to prevent right ventricular failure. CXR, chest x-ray; ECG, electrocardiogram; echo, echocardiography; LA, left atrial; MR, mitral regurgitation; MVA, mitral valve area; MVG, mean mitral valve pressure gradient; NYHA, New York Heart Association; PASP, pulmonary artery systolic pressure; PAWP, pulmonary artery wedge pressure; 2D, 2-dimensional. (From RO Bonow et al: J Am Coll Cardiol 48:e1, 2006; with permission.)

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