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 .


Mitral Stenosis TREATMENT


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). 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).