Broad complex tachycardia


  • Heart rate > 100 beats per minute
  • QRS duration > 0.12 sec ( 3 small squares )

If the patient is unstable, or you are feeling uncertain, do not over-complicate your management. Follow the management algorithm below. Call for expert help.

Differential Dx

Monomorphic VT

If you are more experienced, and circumstances permit, it is possible to make an attempt to diagnose the rhythm more accurately. This may facilitate focussed treatment. It will require knowledge and understanding of the differential diagnosis.

Polymorphic VT

Differential Dx of broad complex tachycardia:

Torsade de Pointes
  • Ventricular tachycardia
    • Monomorphic VT
    • Polymorphic VT
    • Torsade de Pointes
    • Special cases e.g. idiopathic tachycardias and RVOT
  • SVT with with aberrancy
  • SVT with pre-existing BBB
  • Atrial or AV-nodal re-entry tachycardia with pre-excitation (rare)
  • Much more commonly in EM, If QRS >200ms or rate is <120, think hyperkalaemia or drug (e.g. TCAD) overdose and consider Ca++ ± bicarb

Broad complex tachycardia and instability

  • Chest pain or shortness of breath
  • Evidence of poor peripheral perfusion
  • Systolic blood pressure less than 90 mmHg 
  • Pulmonary congestion
  • Altered level of consciousness

The following are adverse

  • Heart rate greater than 150 beats per minute
  • Polymorphic VT
  • Irregular broad complex tachycardia (?AF with alternative pathway)
  • QRS >200ms (one big square) or rate <120 - think toxidrome (e.g. TCAD) or hyperkalaemia

Management Algorithm

Content by Dr Ian Higginson, Dr Íomhar O' Sullivan 11/07/2003.. Reviewed by Dr ÍOS 11/07/2004, 23/04/2007, 23/04/2008. Last review Dr ÍOS 10/06/21.