• Refractory Ventricular Fibrillation (RVF) is defined as ventricular fibrillation that is unresponsive to three or more defibrillation attempts.
• Dual External Defibrillation (DED) is a technique in which two defibrillators are used to treat RVF after failure of traditional Advanced Cardiovascular Life Support (ACLS) measures and defibrillation. DED includes Dual Simultaneous Defibrillation (DSiD – shocks delivered at exactly the same time) and Dual Sequential Defibrillation (DSD – shocks delivered in close sucession). Because it is practically very difficult to defibrillate at exactly the same time, functionally most studies evaluate DSD, as opposed to DSiD.

• There are several theories why DED might work:
  • More Power – Most commercial defibrillators cannot deliver more than 360J, and some studies have shown that more energy results in higher likelihood of ROSC.
  • The Set Up – The first shock lowers the defibrillation threshold and “sets up” a successful second shock.
  • Multiple Vectors – Multiple vectors of energy delivery ensure more of the myocardium is depolarized by the defibrillation.

• There are unlikely to be any iatrogenic complications of DED for the patient, especially given the premorbid state of cardiac arrest.
• However, there can be harm to your defibrillator if not performed correctly. Specific pitfalls include:
  • Using different defibrillators (different brand OR different model).
  • Pads in contact with each other.
  • Simultaneous defibrillation.

• Two IDENTICAL (same brand and model) defibrillators are required. Use of different defibrillators can result in damage to the devices.
• The original pads (DEFIB 1) are placed in the traditional anterolateral position, and will already be on the patient.
• The second set of pads (DEFIB 2) can be placed either Anterior-Posterior (Figure 1) or Anterior (Figure 2).
• NOTE: Defibrillator pads should be close, but NEVER touching each other.

Figure 1. DEFIB 1 positioned anterolateral and DEFIB 2 positioned anterior-posterior.

Figure 2. DEFIB 1 positioned anterolateral and DEFIB 2 positioned anterior.

• One provider should ideally press both shock buttons at approximately (but not exactly) the same time. In theory, simultaneous defibrillation may damage some types of defibrillators and is not recommended by manufacturers.

• DED should be considered in patients with RVF and after traditional ACLS measures (e.g. anti-arrhythmics) have failed. DED should NOT be used for patients with refractory ventricular tachycardia (VT/electrical Storm).
• Given the low quality of evidence for DED, greater consideration should be given to interventions with higher likelihood of patient benefit, if available in your center. For example, activation of your extracorporeal life support team, or transport of the patient with mechanical CPR for percutaneous coronary intervention should take precedent. However, there are many centers where these interventions are not available without ROSC, or not available at all, and DED may be a reasonable intervention.

Dual Sequential Defibrillation Video (EMRAP)

1. Link MS, Berkow LC, Kudenchuk PJ, et al. 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, Part 7: Advanced Cardiovascular Life Support. Circulation. 2015;132:S444–S464.

   
   

2. Cheskes S, Dorian P, Feldman M, et al. Double sequential external defibrillation for refractory ventricular fibrillation: The DOSE VF pilot randomized controlled trial. Resuscitation. 2020;150:178-184. 

   
   

3. Mark Ramzy. Dual External Defibrillation: Close but not touching the Mark. EMCrit Blog. July 13, 2019 (accessed August 27, 2020). 

   
   

4. Leacock BW. Double simultaneous defibrillators for refractory ventricular fibrillation. J Emerg Med. 2014;46(4):472-474. 

   
   

5. Sakai T, Iwami T, Tasaki O, et al. Incidence and outcomes of out-of-hospital cardiac arrest with shock-resistant ventricular fibrillation: Data from a large population-based cohort. Resuscitation. 2010;81(8):956-961.