• Clinical science

Mitral regurgitation (Mitral valve regurgitation)

Abstract

Mitral regurgitation (MR) refers to the leakage of blood from the left ventricle to the left atrium due to incomplete closure of the mitral valve. The most common causes are primary diseases of the valve (e.g., mitral valve prolapse), although damage may also result secondary to other heart conditions such as left ventricular dilation and myocardial infarction. Symptoms such as palpitations or dyspnea appear late in the course of chronic compensated MR in which cardiac output can still be maintained. In acute or chronic decompensated MR, pulmonary edema and pulmonary hypertension often cause dyspnea, coughing, jugular venous distention, and pitting edema. Echocardiography is the most important diagnostic tool and allows for assessment of severity. It may also be used for preoperative evaluation. Treatment options include surgical mitral valve repair or replacement and percutaneous reconstruction. Early intervention is favored in most cases of MR with evidence of left ventricular dysfunction, regardless of symptoms.

Etiology

References:[1][2][3][4]

Pathophysiology

  • Acute MR → ↑ LV end-diastolic volume → rapid ↑ LA and pulmonary pressure → pulmonary venous congestion → pulmonary edema
  • Chronic (compensated) MR: progressive dilation of the LV (via eccentric hypertrophy) ↑ volume capacity of the LV (preload and afterload return to normal values) → ↑ end-diastolic volume → maintains stroke volume (normal EF)
  • Chronic (decompensated) MR: progressive LV enlargement and myocardial dysfunction → stroke volume → ↑ end-systolic and end-diastolic volume → ↑ LV and LA pressure → pulmonary congestion; , possible acute pulmonary edema, pulmonary hypertension, and right heart strain

References:[2][4]

Clinical features

References:[2]

Diagnostics

  • Auscultation
    • See “Auscultation in valvular defects
    • Quiet first heart sound (S1)
    • S3 gallop in advanced stages of disease
    • Holosystolic murmur (high-pitched, blowing)
      • Radiates to the left axilla and heard loudest over the apex (5th ICS at the left mid-clavicular line)
      • Intensity increases with increased systemic vascular resistance (hand grip, squatting)
    • Cardiac impulse is often prominent
  • ECG
  • Chest X-ray
    • Posterior-anterior image
      • LV enlargement: laterally displaced left cardiac border
      • LA enlargement: straightening of the left cardiac border and double density sign: double contour of the right atrial border due to the enlarged left atrium overlapping with the right atrium
      • Signs of pulmonary congestion in late stages of disease (see “X-ray findings in pulmonary congestion”)
    • Lateral image: Narrowing of the retrocardiac space
  • Echocardiography: most important diagnostic method for detecting and assessing valvular abnormalities
    • Valve apparatus (e.g., dimensions of valve opening area, calcification, rupture of the chordae tendineae) and mobility
    • LV and LA size and function
  • Coronary angiography: prior to surgical intervention

Myocardial infarction must be ruled out in patients presenting with acute MR!
References:[5][2][6][7]

Treatment

References:[2][3]

Complications

References:[2]

We list the most important complications. The selection is not exhaustive.