Case of the Month #8 - atrial fibrillation

Published 03/02/2022

How would you manage AF occurring during critical illness?

New onset AF can lead to decompensation of the previously stable patient. Haemodynamic instability can result from impaired ventricular filling due to loss of atrial systole and/or rapid ventricular response to atrial impulses. 

The Unstable Patient:

  • ALS advocates synchronised DC cardioversion when new AF is identified as the precipitant of haemodynamic instability 
  • Markers of haemodynamic compromise are hypotension, pulmonary oedema, cardiac ischaemia and syncope 
  • Synchronised shock should initially be delivered at 120-150J then in increasing increments with up to 3 attempts 
  • Recurrence is common in the critically ill patient. Concurrent medical therapy is advised. ALS favours the use of amiodarone. 

The Stable Patient:

  • Discontinue precipitant medications 
    • Stop beta-agonists if possible 
    • Avoid dopamine and epinephrine 
  • Manage reversible triggers 
    • Treat electrolyte abnormalities: hypokalaemia, hypomagnesaemia 
    • Correct volume status, aim for euvolaemia; increased atrial size on echo has been associated with onset of AF in critical care 
    • Optimise ventilator synchronicity 
    • Treat any myocardial ischaemia 
    • Optimise management of underlying illness 
  • Acute medical management targets different phases of the cardiac cycle  
    • Control of rapid ventricular response: 
      • First line – Beta-blocker (esmolol allows easy titration and discontinuation) 
      • Second line – Calcium channel blockers (verapamil, diltiazem) or digoxin 
    • To target loss of atrial systole or if above options ineffective 
      • First line – Magnesium 
      • Second line – Amiodarone 
    • No changes to anticoagulation are advised during the acute phase of illness