Differentiating VT from SVT with abnormal conduction


Brugada criteria

You can try applying the Brugada criteria to the ECG. The criteria are not 100% reliable.

  • Is there an absent\ce of RS complexes in all the chest leads?
  • Is the R-S nadir ( interval between the start of the QRS complex and the lowest part of the S wave) > 100mS in any V lead?
  • Are there capture beats, fusion beats, or evidence of AV dissociation?
  • Is there an absence of typical classical BBB?

Yes to any = VT, No to all= SVT

If there is any doubt, or you are not sure how to apply these criteria, assume the rhythm is VT


Differentiating Polymorphic VT from AF with pre-excitation

AF in WPW

Features of the ECG in WPW-with Atrial Fibrillation

  • Broad complex tachycardia
  • Irregularly irregular
  • Very short R-R intervals
  • "Pure" delta waves

If there is any doubt treat as for VT but do not use agents that block the AV node ( such as Adenosine )



Content by Dr Ian Higginson, Dr Íomhar O' Sullivan 11/07/03. Reviewed by Dr ÍOS 11/07/04, 19/07/2005, 24/04/2007. Last review Dr ÍOS, Dr Brian O' Riordan 4/12/18.