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MITRAL STENOSIS (MS)

Etiology

Most commonly rheumatic, although history of acute rheumatic fever is now uncommon; rare causes include congenital MS and calcification of the mitral annulus with extension onto the leaflets.

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, 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 when 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 reduced 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. 112).

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. 114-1). In the presence of dyspnea, sodium restriction and oral diuretic therapy; beta blockers, rate-limiting calcium channel antagonists (i.e., verapamil or diltiazem), or digoxin to slow ventricular rate in AF. Warfarin (with target INR 2.0–3.0) for pts with AF or history of thromoembolism. For AF of recent onset, consider conversion (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. 114-1).

FIGURE 114-1

Management of rheumatic mitral stenosis. MR, mitral regurgitation; MS, mitral stenosis; MVA, mitral valve area; MVR, mitral valve surgery (repair or replacement); NYHA, New York Heart Association; PCWP, pulmonary capillary wedge pressure; PMBC, percutaneous mitral balloon commissurotomy; and T ½, pressure half-time. (Adapted from RA Nishimura et al: 2014 AHA/ACC Guideline for the Management of Patients with Valvular Heart Disease. J Am Coll Cardiol 63:e57, 2014.)

MITRAL REGURGITATION (MR)

Etiology

Mitral valve prolapse (see below), rheumatic heart disease, ischemic ...

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