See critical care quick reference for defibrillation settings (joules) by weight.


  • Unsynchronized shock


It is important to note that the procedure and indications differ between defibrillation and cardioversion

Defibrillation (Unsynchronized Cardioversion)

Synchronized Cardioversion


  • None

Equipment Needed

  • Automated External Defibrillator (AED)
  • Defibrillator


  • Apply pads or paddles
    • Paddles may be slightly quicker but pads are viewed to be safer[1]
  • Larger pads reduce transthoracic impedance[2]
    • “Adult” size in adults
    • “Adult” size (8 to 10 cm) for children >10 kg (> approximately 1 year)[3]
    • “Infant” size for infants <10 kg
  • 4 accepted pad positions: anterolateral, anteroposterior, anterior-left infrascapular, and anterior-right-infrascapular
    • Anteroposterior position performs slightly better[4]
  • Biphasic setting
    • Initial 120-200J for VF/pulseless Vtach in adults (Monophasic 360J)[5]
    • Initial 2-4J/kg (Do not exceed J/kg) for pediatric VF/pulseless Vtach[6]
      • Biphasic defibrillates more effectively and at lower energies than monophasic waveforms[7][8]


See Also

External Links


  1. Benedikte H, et al. Time and safety in defibrillation with paddles versus pads: A comparative study of two defibrillation regimes. Resuscitation. 2013; 84(11):e141–e142.
  2. Connell PN, et al. Transthoracic impedance to defibrillator discharge. Effect of electrode size and electrode-chest wall interface. J Electrocardiol. 1973; 6:313–M.
  3. Atkins DL, et al. Pediatric defibrillation: current flow is improved by using “adult” electrode paddles. Pediatrics. 1994; 94:90–93.
  4. Krasteva V, et al. Transthoracic impedance study with large self-adhesive electrodes in two conventional positions for defibrillation. Physiol Meas. 2006; 27:1009–1022.
  5. Neumar RW, et al. 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science. Part 8: Adult Advanced Cardiovascular Life Support. Circulation. 2010; 122: S729-S767.
  6. Kleinman ME, et al. 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science. Part 14: Pediatric Advanced Life Support. Circulation. 2010; 122: S876-S908.
  7. Mittal S, Ayati S, Stein KM, et al. Comparison of a novel rectilinear biphasic waveform with a damped sine wave monophasic waveform for transthoracic ventricular defibrillation. ZOLL Investigators. J Am Coll Cardiol. 1999;34(5):1595-1601. doi:10.1016/s0735-1097(99)00363-0
  8. Schneider T, Martens PR, Paschen H, et al. Multicenter, randomized, controlled trial of 150-J biphasic shocks compared with 200- to 360-J monophasic shocks in the resuscitation of out-of-hospital cardiac arrest victims. Optimized Response to Cardiac Arrest (ORCA) Investigators. Circulation. 2000;102(15):1780-1787. doi:10.1161/01.cir.102.15.1780
  9. Hoch DH, et al. Double sequential external shocks for refractory ventricular fibrillation. J Am Coll Cardiol. 1994; 23(5):1141-5.
  10. Cabanas JG, et al. Double Sequential External Defibrillation in Out-of-Hospital Refractory Ventricular Fibrillation: A Report of Ten Cases. Prehosp Emerg Care. 2015; 19(1):126-130.
  11. Driver BE, Debaty G, Plummer DW, et al. Use of esmolol after failure of standard cardiopulmonary resuscitation to treat patients with ventricular fibrillation. Resuscitation. 2014; 85(10):1337-1341.