Electrical Storm: Don’t Just “Push Another Milligram of Epi”

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Author: Khalid M Miri, OMSIV
Western University of Health Sciences, College of Osteopathic Medicine of the Pacific

"Are you ready to call it?" "Not yet, let’s push one more of epi." Sound familiar? Despite doing proper CPR, defibrillating, and pushing all the ACLS meds, you know deep down that after the first few rounds of chest compressions, your cardiac arrest patient has a tiny chance of surviving to discharge in good neurological condition. You have seen too many codes that go on too long and all you know to do is keep pushing epinephrine and hope that your patient is that one rare case that will achieve sustained ROSC. Have you ever wished you had another option, something that might work when epinephrine and amiodarone do not? Well, an additional option may exist. During a specific condition — refractory ventricular fibrillation — research shows that using a beta blocker can have a better chance of bringing that patient out of their dysrhythmia than when using epinephrine and antidysrhythmics alone.

Cardiac electrical storm (ES) is often defined as three or more episodes of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) within 24 hours. It is a dangerous arrhythmia that leads to refractory VF and will kill most of its victims despite treatment with the current ACLS recommendations of epinephrine, antidysrhythmics, CPR, and defibrillation.[1]

In ES, the sympathetic nervous system is activated leading to a surge of endogenous catecholamines. These catecholamines are likely the reason standard ACLS fails for ES patients. Catecholamines stimulate alpha-adrenergic receptors and cause vasoconstriction, redirect blood flow to central circulation, and thus increase coronary perfusion, which is a lifesaving function during cardiac arrest. However, catecholamines also stimulate the beta-adrenergic receptors which increase heart rate and myocardial oxygen demand, as well as make the patient more susceptible to arrhythmias.[2] Following ACLS guidelines, one would push an exogenous catecholamine (epinephrine) every 3-5 minutes during pulseless VT or VF. This increases the deleterious effects on the heart via beta-adrenergic receptor stimulation. For this reason, a number of studies have explored the role of beta blockers in ES and refractory VF.

Using a porcine model, Zhang et al. tested the benefits of giving epinephrine alone versus epinephrine with esmolol, a beta-1 selective blocker, to pigs in VF.[3] The results of this blinded, randomized, controlled study showed that using esmolol in addition to epinephrine increased mean arterial pressure, improved oxygen metabolism, and increased cardiac output compared to using epinephrine alone.

Nademanee et al. explored the use of sympathetic blockade versus the standard ACLS guided therapy on patients with ES.[1] As ES is refractory by definition and can only be identified after initial treatment fails, ACLS guidelines and medications were used initially on almost all the patients. When the cardiac arrest was found to be refractory VF/VT, the patients were either started on a sympathetic blockade or continued on ACLS guidelines. Of the nonrandomized trial’s 49 patients, 22 received care according to ACLS guidelines and 27 received sympathetic blockade treatment. They found that 82% of patients in the group following standard ACLS guidelines died within a week versus 22% of patients in the sympathetic blockade group. At the one-year follow-up, they found that only 5% of patients in the ACLS guidelines group survived versus 67% of patients in the beta-blockade group.[1]

Miwa et al. also showed a benefit to using a beta blocker in ES. All 42 ES patients in this trial had VT/VF that was resistant to epinephrine, vasopressin, atropine, magnesium, and class III antiarrhythmic drugs and were given landiolol, an ultra-fast-acting beta-1 selective blocker. Landiolol inhibited ES in 33 patients (79%). Of those 33 patients, 76% survived to discharge.[4]

Driver et al. looked at patients in refractory VF and compared those who received standard ACLS therapy to those who received esmolol in addition.[5] This retrospective study analyzed 25 patients; 6 were treated with esmolol and 19 received standard ACLS therapy. Refractory VF was defined as patients whose presenting rhythm was VF or VT and who received at least 3 mg of epinephrine, 300 mg of amiodarone, 3 defibrillation attempts, and remained in VF cardiac arrest. The study found that 32% of ACLS standard therapy patients achieved sustained ROSC vs 67% of patients who received esmolol. Even more significant, the study found that 11% of patients in the ACLS group survived to discharge with favorable neurological outcomes vs. 50% of patients in the esmolol group.

With evidence suggesting potentially significant benefits to using beta blockers in refractory VF, Drs. McGovern and McNamee have suggested a new treatment algorithm for these grim cases.[6] When faced with continued VF arrest after at least 3mg of epinephrine, 300mg of amiodarone (or one dose of another antidysrhythmic), and 3 attempts of defibrillation, use the following algorithm:

• Add a second set of defibrillation pads in the opposite location of the first set. If the patient has pads anterior-posterior, add anterior-apex pads and vice versa (research shows double sequential external defibrillation in refractory VF significantly increases chances to terminate the VF and achieve ROSC vs single pads.)[7-8] 

• Continue high quality CPR and consider withholding further doses of epinephrine. 

• Rhythm check. If VF then defibrillate at 360 J from both sets of pads simultaneously from two separate devices. 

• Bolus esmolol at 0.5 mg/kg and initiate a continuous infusion of esmolol at 0.1mg/kg/hr while CPR continues. 

• Rhythm check. If VF then defibrillate again at 360 J from both sets of pads simultaneously from two separate devices. 

• Continue esmolol infusion along with high-quality CPR and correct electrolytes, if not previously corrected.  

• Terminate CPR if ROSC is achieved or patient is deemed unsalvageable by treating physician.

Cases of refractory VF are often hopeless, but this research shows there might be a new way to treat these patients. Randomized controlled trials using beta-blockers for refractory VF are the next step, but until then it is worth discussing this research and new algorithm with our attendings and deciding whether your team wants to try this new approach before giving up on your next refractory VF arrest. You may save more lives than you thought possible.

References

1. Nademanee K, Taylor R, Bailey WE, Rieders DE, Kosar EM. Treating electrical storm: sympathetic blockade versus advanced cardiac life support-guided therapy. Circulation. 2000;102(7):742-7. PMID: 1094274
2. Gao D, Sapp JL. Electrical storm: definitions, clinical importance, and treatment. Curr Opin Cardiol. 2013;28(1):72-9. PMID: 23160339
3. Zhang Q, Li C. Combination of epinephrine with esmolol attenuates post-resuscitation myocardial dysfunction in a porcine model of cardiac arrest. PLoS ONE. 2013;8(12):e82677. PMID: 24367539
4. Miwa Y, Ikeda T, Mera H, et al. Effects of landiolol, an ultra-short-acting beta1-selective blocker, on electrical storm refractory to class III antiarrhythmic drugs. Circ J. 2010;74(5):856-63. PMID: 20339194
5. Driver BE, Debaty G, Plummer DW, Smith SW. Use of esmolol after failure of standard cardiopulmonary resuscitation to treat patients with refractory ventricular fibrillation. Resuscitation. 2014;85(10):1337-41. PMID: 25033747
6. McGovern T, McNamee J. Emergency interventions for treating cardiac electrical storms. ACEPNow website. http://www.acepnow.com/article/emergency-interventions-for-treating-cardiac-electrical-storms/?singlepage=1. November 18, 2015. Accessed January 1, 2016.
7. Hoch DH, Batsford WP, Greenberg SM, et al. Double sequential external shocks for refractory ventricular fibrillation. J Am Coll Cardiol. 1994;23(5):1141-5. PMID: 8144780
8. Cabañas JG, Myers JB, Williams JG, De maio VJ, Bachman MW. Double Sequential External Defibrillation in Out-of-Hospital Refractory Ventricular Fibrillation: A Report of Ten Cases. Prehosp Emerg Care. 2015;19(1):126-130. PMID: 25243771