Circulation - DC cardioversion
This procedure is performed using procedural sedation (if conscious or stable), which is covered separately
Indications
Unstable tachyarrhythmia
SBP <90mmHg
Altered mental state
Anginal chest pain
APO
or
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)
Alternatives
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
Pain
Failure
Skin burns
Post cardioversion arrhythmia
Myocardial dysfunction and injury (repeated shocks)
Pacemaker malfunction (if pacemaker present)
Thromboembolism
Procedural hygiene
Standard precautions
PPE: non-sterile gloves
Area
Resuscitation bay
Staff
Monitoring clinician, procedural clinician and nurse scribe
Equipment
Defibrillator
Multifunction adult pads
Positioning
Supine 30 degrees head up
Remove jewellery, shave hair, dry chest
Medication
Oxygen 15l via non-rebreathe mask
Consider procedural sedation (covered separately)
or
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)
Sequence
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)
Tips
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)
Discussion
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 ACI-ECIs@health.nsw.gov.au.
References
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: https://resus.org.au/guidelines/
Australian Resuscitation Council. Guideline 11.9 – managing acute dysrhythmias. East Melbourne: ARC; 2009. 11pp. Available from: https://resus.org.au/guidelines/
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: https://www.aci.health.nsw.gov.au/__data/assets/pdf_file/0008/380285/Defibrillation_and_Cardioversion.pdf
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: https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias
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