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Circulation - DC cardioversion

This procedure is performed using procedural sedation (if conscious or stable), which is covered separately


Unstable tachyarrhythmia

SBP <90mmHg

Altered mental state

Anginal chest pain



Stable atrial flutter or fibrillation <48 hours duration

Contraindications (absolute in bold)

Ventricular fibrillation

Unconscious ventricular tachycardia

Digoxin toxicity (potential to degenerate to refractory VF)

Atrial fibrillation or flutter with onset >48h

Sinus tachycardia, multifocal atrial tachycardia, junctional tachycardia (ineffective)


Pharmacological rate or rhythm control

Informed consent

Medical emergency

Consent is not required if the patient lacks capacity or is unable to consent

Brief verbal discussion is recommended if the situation allows

Potential complications



Skin burns

Post cardioversion arrhythmia

Myocardial dysfunction and injury (repeated shocks)

Pacemaker malfunction (if pacemaker present)


Procedural hygiene

Standard precautions

PPE: non-sterile gloves


Resuscitation bay


Monitoring clinician, procedural clinician and nurse scribe



Multifunction adult pads


Supine 30 degrees head up

Remove jewellery, shave hair, dry chest


Oxygen 15l via non-rebreathe mask

Consider procedural sedation (covered separately)


Midazolam 0.5-1mg IV (dose reduced in haemodynamic instability or elderly patients)

Fentanyl 50-100mcg IV (dose reduced in haemodynamic instability or elderly patients)

Ketamine 10-20mg IV (dose reduced in haemodynamic instability or elderly patients)


Dry and clean skin

Place defibrillator ECG electrodes away from where the defibrillation pads are to be placed

Placing pads antero-posterior is preferred (precordium and left Intrascapular region)

Placing pads antero-laterally is also adequate (right parasternum second intercostal space, left mid-axillary line sixth intercostal space)

If pacemaker present place pads >8cm from pulse generator box in AP positions

Ensure R or S wave is bigger than T wave (may induce VF or VT, move pads to avoid this)

Turn defibrillator to ‘defib’ and select ‘sync’ and confirm defibrillator detecting R-waves (marker)

Select 100 Joules energy level and charge defibrillator to 100 joules (1J/kg paeds)

Prepare for charge utilising COACHED mnemonic

Inform team to ‘stand clear’, ensure all clear then discharge shock

If defibrillator unable to discharge synchronised shock reattempt or change to asynchronous shock

Reassess rhythm and patient

If failure to revert repeat above steps Increasing energy to 200J for a maximum of two shocks (2J/kg paediatric patients)

If failure to revert commence medical therapy

Post-procedure care

Observation in monitored bed

Repeat ECG

Discuss further treatment with cardiology team

Document (completion, technique, complications)


We recommend all defibrillation and cardioversion utilised the COACHED mnemonic:

C – continue compressions (if CPR ongoing, not required in cardioversion)

O – oxygen away (unless closed circuit)

A – all else clear

C – charging

H – hands off

E – evaluate rhythm

D – defibrillate or disarm

The anterior-posterior pad position is preferred (higher success at lower energy)

Synchronisation to an R or S wave prevents cardioversion inducing ventricular fibrillation

Synchronisation requires ECG electrodes and pads attached to the defibrillator (or multifunction pads)

Magnesium and potassium IV increases cardioversion success (not recommend for unstable patients)

In failure of implantable defibrillation, set emergency department defibrillator to asynchronous, and attempt cardioversion

Defibrillation can damage pacemakers (discuss with cardiology before or after the procedure)


Higher energy levels may cause increased myocardial dysfunction and injury, as may repeated shocks. SVT and atrial flutter may revert with a lower energy level of 50J however we suggested 100J as standard for simplicity, escalating to 200J if this fails to cardiovert the patient.

Peer review

This guideline has been reviewed and approved by the following expert groups:

Emergency Care Institute

Please direct feedback for this procedure to


Australian and New Zealand Committee on Resuscitation. ANZCOR guideline 11.4 – electrical therapy for adult advanced life support. Melbourne: Australian Resuscitation Council and New Zealand Resuscitation Council; 2016. 12pp.. Available from:

Australian Resuscitation Council. Guideline 11.9 – managing acute dysrhythmias. East Melbourne: ARC; 2009. 11pp. Available from:

NHFA CSANZ Atrial Fibrillation Guideline Working Group, Brieger D, Amerena J, et al. National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand: Australian clinical guidelines for the diagnosis and management of atrial fibrillation 2018. Heart Lung Circ. 2018;27(10):1209-1266. doi:10.1016/j.hlc.2018.06.1043

NSW Agency for Clinical Innovation. Defibrillation and cardioversion. Sydney: ACI; 2015. 12pp. Available from:

Roberts JR, Custalow CB, Thomsen TW. Roberts and Hedges’ clinical procedures in emergency medicine and acute care. 7th ed. Philadelphia, PA: Elsevier; 2019.

Dunn RJ, Borland M, O’Brien D (eds.). The emergency medicine manual. Online ed. Tennyson, SA: Venom Publishing; 2019.

Knight BP. Cardioversion for specific arrythmias. In: UpToDate. Waltham (MA): UpToDate. 2019. Available from:

Murray L, Little M, Pascu O, Hoggett KA. Toxicology handbook. 3rd ed. Sydney: Elsevier Australia; 2015.

Sultan A, Steven D, Rostock T, et al. Intravenous administration of magnesium and potassium solution lowers energy levels and increases success rates electrically cardioverting atrial fibrillation. J Cardiovasc Electrophysiol. 2012;23(1):54-59. doi:10.1111/j.1540-8167.2011.02146.x

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