UOTW #37 Answer

Answer: Fine Ventricular Fibrillation (VF), defibrillate 

This bedside echocardiogram demonstrates subtle disorganized cardiac twitching consistent with ventricular fibrillation.

  • It can be difficult to differentiate fine ventricular fibrillation from asystole during CPR pulse checks.1
  • A delay in the diagnosis of ventricular fibrillation decreases the likelihood of successful defibrillation and return of spontaneous circulation (ROSC).2
  • On the other hand, unnecessarily shocking a patient in asystole will not improve that patient’s chance of ROSC and could delay standard therapy: effective chest compression with minimal pauses.
  • Compare and contrast the above clip of VF to this one of asystole and cardiac standstill:
  • The easiest way to differentiate these echocardiograms is to zero in on the mitral valve to look for any disorganized fluttering.
  1. Stewart JA. The prohibition on shocking apparent asystole: a history and critique of the argument. Am J Emerg Med. 2008;26:(5)618-22. [pubmed]
  2. Herlitz J, Bång A, Holmberg M, Axelsson A, Lindkvist J, Holmberg S. Rhythm changes during resuscitation from ventricular fibrillation in relation to delay until defibrillation, number of shocks delivered and survival. Resuscitation. 1997;34:(1)17-22. [pubmed]
  1. Thanks for the post,

    I wonder if ultrasound during VF is akin to CXR for tension pneumothorax.
    The patient seemed to have fibrillation on their rythym strip and no pulse = defibrillate in my book. Would there possibly be a delay in defib and quality continuous CPR by using USS to diagnose VF?


    1. I see your point. In this case there was a question by the providers if the rhythm was asystole vs fine VF. I agree that it is very suggestive of VF, and when in doubt erring on the side of shocking this rhythm is probably the appropriate management. The ultrasound here is unequivocal, however.

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