Defibrillator pads are an easily accessible tool in any ED or ALS vehicle around the world and are placed within seconds of finding a patient in cardiac arrest. There are two universal locations for defibrillator pads to be placed: anterior-posterior or anterior-apex. When we approach a patient in cardiac arrest, the pads are positioned into one of these two positions. Defibrillation remains the mainstay of treatment for VF arrest, but in the rare incidence of ES with refractory VF arrest, the standard ACLS algorithmic approach of increasing voltage through one set of pads may not terminate the dysrhythmia. Hoch et al published a case series in 1994, “Double Sequential External Shocks for Refractory Ventricular Fibrillation,” in which they utilized two sets of external pads placed in both universal pad placement areas to deliver simultaneous shocks to patients who were in

refractory VF unresponsive to standard therapies while in an electrophysiology lab.⁵ They were able to terminate all the patients in the case series from VF into a perfusing rhythm by delivering double sequential shocks by means of two defibrillators, each with their own electrodes, one set placed anterior-posterior and the other set anterior-apex (see Figure 1). Prior animal studies using double sequential defibrillation suggested the sequential shocks lowered the threshold for defibrillation, improving the odds of terminating the

rhythm. This concept was reintroduced to emergency medicine in 2015 with a prehospital retrospective case series published in Prehospital Emergency Care by Cabañas et al.⁶ They included 10 patients with out-of-hospital cardiac arrest who had received at least five defibrillation attempts at 360 J along with standard therapy for refractory VF arrest in this case series. A second set of defibrillator pads was placed opposite the first set of pads, and on the next rhythm check, if shock was advised, the shock was delivered at 360 J from the new pad placement. If VF arrest continued, EMS utilized both sets of pads, and shocks were delivered from both machines as synchronized as possible. EMS providers were able to terminate ventricular fibrillation in 70 percent of the patients after double sequential external defibrillation (DSED), and 30 percent achieved ROSC in the field. Unfortunately, none survived to hospital discharge in this case series. However, they were able to gain ROSC in patients who were previously resistant to all other treatment strategies. What if DSED was combined with esmolol to counteract the sympathetic surge? The combination of both treatment strategies that are commonly available to all ED providers may provide some hope for these seemingly helpless cases. With very little downside of employing these interventions in a refractory VF arrest patient, ED providers can try this Hail Mary to treat the patient’s ES.

The New Playbook: Electrical Storm Treatment Algorithm

We suggest employing the following treatment algorithm (see Figure 2) when faced with your next refractory ventricular fibrillation cardiac arrest patient. For our algorithm, we define refractory VF arrest as at least 3 mg epinephrine, 300 mg amiodarone (or one dose of another antidysrhythmic), and three attempts of defibrillation with continued ventricular fibrillation.