The patient certainly looks uncomfortable as EMS roles him in. He is sweaty and anxious. As they roll down the EMS hallway, he gives a sharp scream of pain. “He’s been doing that for an hour doc. He has an ICD in place, and it is going off every 5 minutes or so. The monitor has been showing V Tach. The shocks seem to work about half the time, but only briefly. The ICD was placed because of a V tach arrest 2 years ago. He has a history of ischemic heart disease. His latest vitals are HR 186, BP 105/60, RR 24, and he is satting 93% on room air.” You pull the closet resident into the room. “Have you ever managed electrical storm?”
Although there is no widely agreed upon definition of electrical storm, it is generally defined as more than 2 or 3 sustained episodes of ventricular tachycardia, ventricular fibrillation, or appropriate ICD shocks during a 24-hour period. (Gao 2013) In emergency medicine and critical care, this diagnosis becomes particularly important when the patient is experiencing sequential ventricular dysrhythmias, with little to no time between, resulting in frequent painful ICD shocks or cardiovascular instability.
My approach to electrical storm
Start with the basics. Manage the airway if necessary and provide oxygen if the patient is hypoxic (in this case I’d use a cutoff of 93%). If the patient arrests, perform CPR and follow the standard ACLS algorithms.
Airway management deserves a specific mention. The medications we use for RSI and the transition to positive pressure ventilation can both worsen hemodynamics, so managing the airway must be approached with caution in patients with hemodynamic compromise. On the other hand, recurrent ICD shocks can be incredibly painful and distressing, so early intubation may be indicated simply for patient comfort. (The approach to analgesia and sedation is discussed further below).
If there is a pulse, use synchronized cardioversion. If there is no pulse, defibrillate. If they have an ICD in place, it will do this step for you. However, even if there is an ICD in place, it is a good idea to have external defibrillation pads on and ready, because if the ICD fails to convert them, that is your next step. Additionally, because ICDs fire based on the heart rate, and the medications we are going to use might slow the arrhythmia, the ICD may stop firing even if the patient is still in (slower) ventricular tachycardia. (Iftikhar 2016)
Should I use a magnet?
Placing a magnet on an ICD will stop the ICD from delivering shocks. It will have no effect on the ICD’s pacing capabilities. In general, unless the patient has decided to change their goals of care, we want the ICD to shock. It is saving the patient’s life. However, occasionally an ICD will be firing inappropriately. This can happen with rapid sinus tachycardia, because the ICD only detects the rate, not the specific rhythm. If you think the ICD is firing inappropriately (ie, this is not actually electrical storm), place a magnet over the ICD to deactivate it.
Note: This is a point of significant practice variation. My approach is to let the ICD do its job. Others approach this differently. They suggest placing a magnet on early, unless the rhythm is clearly not perfusing. Even if the rhythm is ventricular tachycardia, there is a chance it will be stable. Turning off the ICD gives you time to treat the arrhythmia medically and eliminates the patient’s source of pain and anxiety, lowering their sympathetic tone, which is essential for terminating electrical storm.
Consider: Is this Torsades des Pointes or Brugada syndrome?
Although rare, these syndromes require different management, so it is worth considering if the patient has a history of Brugada, or an ECG with either QT prolongation or signs of Brugada. (Eifling 2011) See below for specific management.
Although antiarrhythmics don’t seem to help dead patients and so I don’t generally use them in cardiac arrest, an electrical storm patient with a pulse, or even a very recent pulse, is a different scenario. (Kudenchuk 2016) Start an antiarrhythmic. My preference is procainamide, based on the PROCAMIO trial. (Ortiz 2017)
Procainamide 10 mg/kg over 20 minutes
I think the benefit of amiodarone has been oversold for most conditions, but it is a reasonable second line option here. (Many authors list it as their first option, but with limited evidence). Chronic use of amiodarone has been shown to decrease the incidence of frequent ventricular dysrhythmias in these patients. (Connolly 2006) Boluses of 150mg, followed by an infusion of 1 mg/min are reasonable.
Lidocaine IV is another reasonable option.
Chill them out
Electrical storm is frequently associated with a catecholamine surge, either as the cause of the arrythmias, or as a result of the frequent shocks and underlying etiology. Treatment is aimed at counteracting that sympathetic tone, which includes analgesia, sedation, and beta-blockers.
Analgesia and anxiolysis
Analgesia and anxiolysis will help decrease the patient’s overall sympathetic tone, which might be contributing to electrical storm. Even more importantly, recurrent cardioversions or defibrillations are painful and frightening. Patients will almost always require some degree of sedation. The choice of agent will depend a lot of the patient’s hemodynamics.
I asked twitter this question and got a large range of answers. The conversation was interesting, and is worth checking out:
Ketamine is my first choice in this scenario. It provides both analgesia and dissociation, if necessary. It is easy to titrate. It does not directly suppress cardiac function or cause vasodilation. And it generally leaves the patient’s airway reflexes intact (although I am always prepared for deterioration and the need for intubation). Although ketamine is associated with tachycardia in healthy patients, once a patient is already in sympathetic overdrive, it doesn’t seem to worsen sympathetic tone, and in fact heart rate often falls after ketamine administration in critically ill patients.
Continued ventricular arrhythmias unresponsive to anti-arrhythmic therapy should receive sympathetic blockade. (Nademanee 2000) In the first few minutes in the resuscitation room my preference is esmolol because it is rapidly reversible if the patient’s blood pressure drops. (Miwa 2010; de Oliveira 2012; Driver 2014; Lee 2016)
Esmolol 500 mcg/kg IV push, then an infusion of 50-100 mcg/kg/min.
Longer term therapy is less clear, but there are a number of pharmacologic reasons to think that propranolol is the best choice. I am not smart enough to understand all the physiology, so I would suggest reading this post by PharmD Kristina Kipp. There is an RCT showing better outcomes using oral propranolol as compared to oral metoprolol. (Chatzidou 2018) Once I am satisfied with the patient’s hemodynamics, I would add 40mg of oral propranolol.
In refractory cases, intubation and general anesthesia, both for comfort and to reduce the sympathetic overdrive, may be necessary. (Eifling 2011) Propofol is widely recommended, but propofol is a cardiac depressant, which should probably be avoided in ventricular arrhythmias with borderline hemodynamics. If there is any concern about hemodynamics, I would stick to ketamine as my first line agent. (See the post: Is this patient ready for intubation?)
Reverse the underlying cause
Everything else we do is pointless if we don’t address the underlying cause.
If you can catch the patient out of V Tach, get an ECG. If there is STEMI, the patient needs a cath lab. Also look for other causes of ventricular tachycardia, such as a long QT or Brugada syndrome. Only 10-25% of patients will have a reversible cause identified, but they are important when we find them. (Gao 2013; Iftikhar 2016)
Causes to consider: (Gao 2013; Eifling 2011; Iftikhar 2016)
Pause: Is this really ventricular tachycardia?
When things aren’t proceeding as you expect, then next step should be to reassess your assumptions, which in medicine means reconsidering your diagnosis. Underlying bundle branch blocks and rate related conduction abnormalities can make supraventricular tachycardias look a lot like ventricular tachycardias. Some might suggest taking the time to diagnosis the arrhythmia earlier in the patient’s management, but I think the safest strategy is to just assume that wide complex tachycardia is ventricular tachycardia. (Eifling 2011) 70-80% of ICD shocks are appropriate (for V tach or V fib), so it is a good guess. (Iftikhar 2016) Furthermore, the management up until now (cardioversion, beta-blockade, and antiarrhythmics) would be reasonable for atrial fibrillation, flutter, AVRT, and AVNRT. However, none of this will help if the patient is actually in sinus tachycardia, so taking a pause and thinking about the diagnosis is important at this point. (Newer ICDs are capable of comparing the atrial and ventricular rates, and so are able to distinguish SVT from VT). (Iftikhar 2016)
If you have made it this far down the algorithm, you are going to need some help. There are a number options described, but all require expertise beyond what we provide in the emergency department.
A left stellate ganglionic block can be attempted. (Nademanee 2000; Patel 2011)
Ablation has been used to both terminate electrical storm and also prevent recurrence. (Gao 2013).
If there is a reversible underlying cause, or cardiac transplantation is an option, then ECMO or an LVAD may also be considered.
Management of specific diagnoses
Torsades des Pointes
- In stark contrast to the above approach, the first line agent to consider in patients with Brugada syndrome is isoproterenol. (Maury 2005) Excessive vagal tone is thought to contribute to the occurrence of ventricular fibrillation in these patients. Increasing sympathetic tone with isoproterenol has been shown to normalize the ST segments in V1-V3, and prevent Vfib. (Jongman 2007)
- The other option for these patients is a class 1a antiarrhythmic, such as quinidine. (Maury 2005)
- Finally, use of general anesthesia has been reported. (Maury 2005)
This general approach is adopted from an excellent talk by the incomparable Dr. Sara Gray at the North York General Emergency Medicine Update conference. A huge thanks to Drs. Sara Gray, Anand Swaminathan, and Casey Parker for providing expert peer review for this post.
Like a lot of resuscitation topics, there is very limited evidence for all of the above, and much has to extrapolated from animal models and case reports, or is based on expert opinion.
My recent move to New Zealand has illustrated an important point about these resuscitation plans: the same drugs are not available everywhere in the world. These plans should always be adapted to your own practice, whether it is the availability of different drugs, different equipment, or different personnel. I can’t pretend to know all the drugs in the world, so I will keep writing what I know, and allow you to make appropriate adjustments for your own practice.
Placing a magnet on a pacemaker will switch the pacemaker to asynchronous (fixed rate) pacing with no sensing and no inhibition. Placing a magnet on an ICD will stop the ICD from delivering shocks. It will have no effect on the ICD’s pacing capabilities.
Not all patients will experience pain when their ICD terminates an important arrhythmia. Antitachycardia pacing uses overdrive pacing to terminate ventricular tachycardia, and is significantly less painful than cardioversion, and may not even be felt by the patient. (Iftikhar 2016)
Other FOAMed Resources
Emergency Medicine Cases: Esmolol in Refractory Ventricular Fibrillation
CanadiEM: ß-Blockers in Cardiac Arrest
Chatzidou S, Kontogiannis C, Tsilimigras D, et al. Propranolol Versus Metoprolol for Treatment of Electrical Storm in Patients With Implantable Cardioverter-Defibrillator. J Am Coll Cardiol. 2018;71(17):1897-1906. [PubMed]
Connolly SJ. Comparison of β-Blockers, Amiodarone Plus β-Blockers, or Sotalol for Prevention of Shocks From Implantable Cardioverter Defibrillators.The OPTIC Study: A Randomized Trial. JAMA. 2006; 295(2):165-171.
de Oliveira FC, Feitosa-Filho GS, Ritt LE. Use of beta-blockers for the treatment of cardiac arrest due to ventricular fibrillation/pulseless ventricular tachycardia: a systematic review. Resuscitation. 2012; 83(6):674-83. [pubmed]
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Eifling M, Razavi M, Massumi A. The evaluation and management of electrical storm. Tex Heart Inst J 2011;38(2):111–121. PMC3066819
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Jongman JK, Jepkes-Bruin N, Ramdat Misier AR, et al. Electrical storms in Brugada syndrome successfully treated with isoproterenol infusion and quinidine orally. Netherlands heart journal : monthly journal of the Netherlands Society of Cardiology and the Netherlands Heart Foundation. 2007; 15(4):151-5. [pubmed]
Kudenchuk PJ et al. Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest. NEJM 2016. PMID: 27043165
Lee YH, Lee KJ, Min YH, et al. Refractory ventricular fibrillation treated with esmolol Resuscitation. 2016; 107:150-155.
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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. Circulation journal : official journal of the Japanese Circulation Society. 2010; 74(5):856-63. [pubmed]
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Ortiz M, Martin A, et al. Randomized comparison of intravenous procainamide versus intravenous amiodarone for the acute treatment of tolerated wide QRS tachycardia: the PROCAMIO study. Eur Heart J. 2017 38;1329-1335.
Patel RA, Priore DL, Szeto WY, Slevin KA. Left stellate ganglion blockade for the management of drug-resistant electrical storm. Pain medicine (Malden, Mass.). 2011; 12(8):1196-8. [pubmed]