Mitral Stenosis

Aka: Mitral Stenosis

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II. Causes

  1. Rheumatic Fever
  2. Congenital Mitral Stenosis

III. Pathophysiology

  1. Increased left atrial pressure
    1. Pulmonary Vasoconstriction
    2. Pulmonary Hypertension
    3. Right Ventricular Failure
  2. Decreased Cardiac Output

IV. Symptoms

  1. Symptoms of Left Ventricular Failure
    1. Dyspnea on exertion
    2. Orthopnea
    3. Paroxysmal Nocturnal Dyspnea
    4. Cough
  2. Symptoms of Right Ventricular Failure
  3. Other Symptoms
    1. Hemoptysis
  4. Precipitating Factors
    1. Exertion
    2. Fever
    3. Anemia
    4. Pregnancy
    5. Sexual intercourse
    6. Atrial Fibrillation

V. Signs: Precordial Exam

  1. Diastolic Thrill
  2. Diastolic Murmur at apex
    1. Apical, low pitched rumbling in mid-diastole
    2. Loudest in early diastole
    3. Crescendo at end of diastole (presystolic)
    4. Accentuating factors
      1. Left lateral decubitus position
      2. Stethoscope bell
      3. Brief Exercise (e.g. brief walk in hallway)
  3. Opening snap of mitral valve cusp
    1. Heard at 3rd - 4th interspace at left sternal border
  4. Accentuated P2 heart sound
  5. Accentuated M1 heart sound
  6. Diminished M2 heart sound

VI. Signs: Later findings of Right Ventricular Failure

  1. Accentuated precordial thrust of right ventricle (lift)
  2. Elevated neck veins
  3. Ascites
  4. Edema

VII. Complications

  1. Hemoptysis
  2. Pulmonary Embolism
  3. Pulmonary infection
  4. Systemic emboli
  5. Endocarditis (uncommon)

VIII. Electrocardiogram

  1. Atrial Fibrillation
    1. Occurs secondary to severe atrial hypertrophy
    2. Most common complication of Mitral Stenosis
    3. High risk for Thromboembolism (esp. Cerebrovascular Accident)
  2. Left atrial enlargement
    1. Stenosed mitral valve impedes flow from left atrium to left ventricle
  3. Signs Pulmonary Hypertension
    1. Right Axis Deviation
    2. Right Ventricular Hypertrophy

IX. Imaging

  1. Chest XRay
    1. Left atrial enlargement
    2. Right Ventricular Enlargement
    3. Posterior displacement of Esophagus
    4. Mitral valve calcification
    5. Kerley B Lines
  2. Echocardiogram (Study of choice)
    1. Mitral valve leaflet changes
      1. Inadequate separation of valve leaflets
      2. Valve leaflet calcification and thickening
    2. Doppler estimates transvalvular gradient

X. Course

  1. Slow, progressive, life-long course
  2. Latent period of 20 to 40 years after Rheumatic Fever
  3. Rapid acceleration of symptoms in later life

XI. Management

  1. Rheumatic Fever prophylaxis until age 35 years
    1. Benzathine Penicillin G 1.2 MU IM qMonth OR
    2. Penicillin VK 125-250 mg PO bid
  2. SBE Prophylaxis
  3. Treat complications and associated conditions
    1. Atrial Fibrillation
    2. Congestive Heart Failure
    3. Anticoagulation for history of emboli
  4. Surgery
    1. Open Mitral valvuloplasty Indications
      1. Mitral orifice <= 1.2 cm2
      2. Cardiopulmonary symptoms
      3. Not a candidate for balloon valvotomy
    2. Percutaneous balloon valvuloplasty (Valvotomy)
      1. Indications
        1. NYHA Class II, III, IV moderate Mitral Stenosis
      2. Contraindications
        1. Non-pliable or calcified valve
        2. Subvalvular distortion
        3. No significant Mitral Regurgitation

XII. References

  1. Kondos (1998) CMEA Medicine Review Lecture, San Diego
  2. Assi (1998) Postgrad Med 104(6):99-110 [PubMed]
  3. Bonow (1998) Circulation 98:1949-84 [PubMed]
  4. Carabello (1997) N Engl J Med 337(1):32-41 [PubMed]
  5. Shipton (2001) Am Fam Physician 63(11):2201-8 [PubMed]

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