Management of MR

Acute MR associated with acute myocardial infarction has a poor prognosis. The 30-day mortality is 34% and 54% by 1 year. Acute papillary muscle rupture in acute myocardial infarction is associated with 75% mortality without surgery within 24 hours [9]. MR in AMI may be due to posterior papillary muscle dysfunction with posterior wall infarction or dilatation of the mitral annulus with diffuse infarction of the LV or LV aneurysm formation. Rapid recognition of this complication of myocardial infarction is important. Blood cultures should be taken in any patient with acute MR and no obvious infarct.

There are a number of emergency measures to be undertaken when managing mitral regurgitation in the ED, and these are shown opposite.

Emergency measures

  • Contact specialist services as the patient may need surgical intervention as an emergency
  • Treat acute myocardial infarction if this is the underlying cause
  • Treat pulmonary oedema
    • This may be difficult if the patient is in cardiogenic shock. Intubation and positive pressure ventilation should be considered early. CPAP can be helpful. Reduce preload and afterload with nitrate infusion and ACE inhibitors if tolerated. Diuretics and inotropes may also be needed. Patients with cardiogenic shock with acute MR may benefit from intra aortic balloon pump
  • Treat AF
    • Acute presentations of chronic MR are usually related to the onset of AF. Therapy is directed at reducing afterload to reduce LV work and controlling AF

Learning bite

Acute MR associated with myocardial infarction is a cardiovascular emergency and may require surgical intervention.