Mitral regurgitation

• Mitral regurgitation (MR) occurs when there is backflow (regurgitation) of blood from the left ventricle into the left atria (through the mitral valve) during ventricular systole.
• Mitral regurgitation is associated with a pansystolic murmur heard loudest over the mitral area and radiating to the axilla.
• Mitral regurgitation can be either acute or chronic.

  Causes of mitral regurgitation include:

  • Infective endocarditis
  • Acute myocardial infarction with rupture of papillary muscles
  • Rheumatic heart disease
  • Congenital defects of the mitral valve
  • Cardiomyopathy
• Typical features of mitral regurgitation murmur include:

  • A pansystolic murmur heard loudest over the mitral area
  • Radiation of the murmur to the axilla
  • Loudest on expiration in the left lateral position
  • Displaced, hyperdynamic apex beat
• Mitral regurgitation is the second most common indication for valvular surgery (the most common being aortic stenosis).
• Acute MR: characterised by the rapid development of heart failure with inadequate cardiac output and flash pulmonary oedema. Patients may be shocked and breathless, the condition is potentially life-threatening, and can necessitate emergency surgery.
• Investigations:

  • ECG - may show recent MI, atrial fibrillation, LVH
  • CXR
  • Echocardiogram - diagnostic
• CXR findings:

  • Chronic MR - left atrial and ventricular enlargement - left atrial enlargement causes a double right heart border
  • Acute - usually no cardiomegaly, pulmonary oedema
• Acute MR management:

  • Usually profoundly unwell - shock and flash pulmonary oedema
  • Medical stabilisation before emergency surgery
  • Valve repair or replacement
• Chronic MR with HF:

  • Medical - ACE inhibitors, beta-blockers and diuretics
  • Surgery - valve repair/replacement, ventricular assist devices, cardiac resynchronization therapy, and heart transplantation