Valve

Mitral Regurgitation

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Mitral Regurgitation, Mitral Valve Papillary Muscle Rupture

  • Precautions
  1. Evaluation and management here focuses on chronic Mitral Regurgitation
  2. Acute Mitral Regurgitation with papillary muscle rupture is also described, but requires emergent management
  • Pathophysiology
  1. Dysfunction of any of the mitral valve structure may result in Mitral Regurgitation
    1. Mitral valve leaflets
    2. Chordae Tendinae
    3. Papillary muscles
    4. Mitral annulus
  2. Chronic Early or compensated Mitral Regurgitation
    1. Volume overload
    2. Left Ventricular Hypertrophy
    3. Left atrial enlargement
  3. Chronic Late or decompensated Mitral Regurgitation
    1. Left Ventricular Failure
    2. Decreased ejection fraction
    3. Pulmonary congestion
  4. Acute Mitral Regurgitation due to papillary muscle rupture
    1. Typically affects posteromedial papillary muscle (most tenuous blood supply)
  • Causes
  • Acute Mitral Regurgitation (due to papillary muscle rupture)
  1. Common causes of papillary muscle rupture
    1. Acute Myocardial Infarction
      1. Associated with 50% acute mortality rate
  2. Rare causes of papillary muscle rupture
    1. Infective Endocarditis
    2. Mitral Valve Prolapse
  • Causes
  • Chronic Mitral Regurgitation
  1. Rheumatic Heart Disease (50%)
  2. Mitral Valve Prolapse
  3. Ischemic Heart Disease and papillary muscle dysfunction
  4. Left Ventricular dilatation
  5. Mitral annular calcification
  6. Hypertrophic Cardiomyopathy
  7. Infective Endocarditis
  8. Congenital Mitral Regurgitation
  • Symptoms
  1. Dyspnea
  2. Fatigue
  3. Weakness
  4. Cough
  • Signs
  1. Holosystolic Murmur at Apex
    1. Harsh, medium pitched pansystolic murmur (without respiratory variation)
    2. Murmur obliterates M1
    3. Radiation
      1. Axilla
      2. Upper sternal borders
      3. Subscapular region
    4. Modifiers
      1. Murmur intensity decreases with squatting
      2. Murmur intensity increases with standing
  2. Other heart sounds
    1. Soft or diminished First Heart Sound (S1)
    2. P2 heart sound augmented
    3. S2 Heart Sound with wide split
    4. S3 Gallop rhythm (indicative of severe disease)
  3. Other findings
    1. Accentuated, hyperdynamic and displaced precordial Apical Thrust
    2. Systolic thrill
    3. Sharp carotid upstroke (contrast with the delayed and decreased pulsation of Aortic Stenosis)
  • Imaging
  1. Chest XRay
    1. Enlarged left atrium
    2. Dilated left ventricle
  2. Echocardiogram
    1. Most important study in the evaluation of Mitral Regurgitation
    2. Test Sensitivity: 65-85%
    3. Associated Findings
      1. Enlarged left atrium
      2. Hyperdynamic left ventricle
      3. Doppler assesses severity
  • Monitoring
  1. Annual or semi-annual Echocardiogram
    1. Assess ejection fraction
    2. Assess end-systolic dimension
  • Management
  1. SBE Prophylaxis
  2. Anticoagulation in Atrial Fibrillation
  3. Treat Congestive Heart Failure
    1. Diuretics
    2. Digoxin
    3. Afterload reduction
      1. ACE Inhibitor
      2. Hydralazine
      3. Nitroprusside IV
      4. Milrinone (also inotropic)
  4. Surgery: Mitral Valve repair or replacement
    1. Repair before Heart Failure develops
      1. Keep ejection fraction >60%
      2. Keep end-systolic dimension <45 mm
    2. Indications
      1. Cardiopulmonary Symptoms
      2. Left Ventricular function impaired