DC cardioversion

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Indications for DC cardioversion:

  • Treatment of a tachyarrythmia that has been present for less than 24 hours with an aim to revert to sinus rhythm.
  • Treatment of a tachyarrythmia that has been present for less than 24 hours when pharmacological measures have failed.
  • Treatment of a tachyarrythmia when the patient shows signs of decompensation:
    • Chest pain, confusion, hypotension or signs of heart failure

 

 Equipment and staff required for DC cardioversion:

  • An anaesthetist for safe sedation
  • Defibrillator
  • Cardiac monitor
  • Defibrillator pads

N.B. In some hospital trusts cardioversion may be done under trans-oesophageal echo (TOE) guidance to ensure there is no right atrial thrombus. Liaise with the cardiology team if you think this is necessary.

 

Contraindications to DC cardioversion:

  • No clear onset of the history of palpitations
  • Previous paroxysms of tachyarrythmia and not on anticoagulation
  • Known atrial thrombus

 

 Pre-procedure:

  • Gain written consent from the patient
    • Risks of sedation; pain (musculoskeletal or minor skin injury); failure (approx. 20%); stroke (<1%); bradycardia
  • Ensure the area where de-fibrillator pads are to be placed is shaved and dry and that jewellery is removed
  • Ensure cardiac monitoring is in place
  • Ensure anaesthetist is happy for you to proceed

 

 Procedure for DC cardioversion:

  • Place the defibrillator pads to ensure the current will pass across the heart.
    • This can be in the conventional position, anterio-posterior, postero-lateral or bi axillary
  • Sedation as necessary
  • Turn on the defibrillator and press ‘Sync’
  • Check your trusts’ policy on level of energy but a rough guide is 100J,150J, 200J
  • Charge the defibrillator ensuring everyone is clear including the oxygen
  • Deliver a safe shock as per ALS guidelines
  • Confirm presence of a pulse
  • Check the monitor for sinus rhythm
    • Two further shocks (escalating energy) can be given if necessary.

 

Video (from the US) on elective DC cardioversion – note some differences from the method described above but principles are the same.

 Post-procedure:

  • Continue cardiac monitoring
  • Post-procedure observations
  • Request cardiology review for further investigation, medication and follow up

 

 In event of failure:

  • Continue cardiac monitoring
  • Contact the cardiology team for assistance
  • Consider use of further anti-arrhythmic medication if appropriate

 

 Top Tips for DC cardioversion:

  • ALWAYS REMEMBER TO CHECK THAT SYNC IS ON PRIOR TO DELIVERING THE CARDIOVERSION SHOCK
    • After one shock some defibrillators will turn off the sync automatically.
  • ALWAYS ENSURE THAT YOU ARE GOING TO DELIVER A SAFE SHOCK.
  • Follow the consent procedure carefully. Many hospitals will have specific consent forms for DC cardioversion.
    • It is worth telling the patient the area where the pads are placed may have some burning or pain after the procedure

 

Click here to download free teaching notes on DC cardioversion: Procedures – DC Cardioversion

Perfect revision for medical students, finals, OSCEs and MRCP PACES