Refractory ventricular arrhythmias (RVAs), also known as electrical storm, refers to three or more episodes of ventricular fibrillation/ventricular tachycardia within 24 hours.1,2 Ventricular arrhythmias are life-threatening, difficult to treat, and often involve hemodynamic collapse. An episode of a ventricular arrhythmia is an emergency and requires immediate intervention to avoid further compromise to vital organs that are deprived of oxygen due to inadequate blood flow.1 The incidence of RVAs can vary among different patient populations. Patients predisposed include those with an acute or past myocardial infarction, heart failure, hyperthyroidism, electrolyte abnormalities, increased catecholamine levels, and excessive sympathetic outflow. Refractory ventricular arrhythmia also occurs in 10%-20% of patients within the first few years of receiving an Implantable Cardioverter-Defibrillator (ICD), a device implanted to prevent Sudden Cardiac Death.2 Treatment options vary and are dependent on the type of ventricular arrhythmia. The management of these patients focuses on stabilization of the cardiac rhythm and hemodynamics.
Current management strategies for a patient with ventricular arrhythmias depend on clinical presentation and stability. Clinically, a patient may present with palpitations, dizziness or syncope, but this condition is often abruptly followed by cardiac arrest. The American Heart Association (AHA) has specific Advanced Cardiac Life Support (ACLS) guidelines for management of stable/unstable tachycardia and cardiac arrest.3 A step-by-step algorithm for treating each condition is detailed in the guideline. According to the AHA, stable tachycardia of greater than 150 beats per minute is treated with pharmacologic interventions, and the drug of choice is dictated by the presentation of the arrhythmia. Pharmacologic treatments include adenosine, amiodarone, procainamide and sotalol. Unstable tachycardia that causes hypotension, altered mental status, or chest discomfort is treated with synchronized electrical cardioversion. If cardiac arrest from a ventricular arrhythmia occurs, it is treated with cardiopulmonary resuscitation, defibrillation and alternating doses of epinephrine and amiodarone. The primary overall goal of ACLS guidelines is the return of spontaneous circulation with a perfusing cardiac rhythm.3
When the condition is refractory to treatment, the prognosis of patients who experience ventricular arrhythmias remains poor, and a diagnosis is often associated with an increased mortality.2 A high mortality rate is evident even with standard ACLS treatment guidelines. According to a study by Nademanee et al. in 2000, 18% of patients that received treatment for RVAs with standard ACLS guidelines survived.3 The AHA has regular updates of ACLS guidelines to meet current evidence-based research, and in 2016 the survival rate to discharge was 24.8% for in-hospital cardiac arrest; this statistic includes cardiac arrest as a result of ventricular arrhythmias as well as asystole/pulseless electrical activity.5 In 2015, a retrospective study by Siao et al. compared treatment of 209 patients with refractory ventricular fibrillation using conventional cardiopulmonary resuscitation and extracorporeal cardiopulmonary resuscitation.6 The rate for return of spontaneous circulation was 27.5% for the conventional cardiopulmonary resuscitation method, but of those patients, only 7.5% attained neurologically optimal outcomes.6
Recurrent ventricular arrhythmias have proven to be problematic as they are often refractory to standard anti-arrhythmic therapy.4,7 Due to the refractory characteristics of RVA, treatment modalities are frequently multimodal and include the following: correcting the contributing factors, antiarrhythmic drug therapy, extracorporeal membrane oxygenation, catheter ablation, implantation of a cardiac defibrillator, supportive care and cardiac sympathetic blockade.8-10 The most immediate concern for patients with a ventricular arrhythmia is hemodynamic stabilization as treatment with ACLS precedes other modalities.
Sympathetic activity plays a large role in RVA.4 The sympathetic system stimulates the heart by releasing norepinephrine causing increases in activity, both by rate and force of contraction.11 The logic behind the use of beta blockers in patients with ventricular arrhythmias is the increase in sympathetic activity.4,7,12 While beta blockade is a common way to perform sympathetic blockade, ventricular arrhythmias do not always respond to this treatment. When beta blockade fails to work, other more invasive interventions can be used to reduce sympathetic activity to the heart by way of the stellate ganglion.
The stellate ganglion provides a pathway of sympathetic innervation to the head, neck and upper extremities.13 This innervation consists of a collection of sympathetic fibers located anterior to C7 and composed by the fusion of the inferior cervical ganglion and first thoracic ganglion. The stellate ganglion occurs bilaterally and is found in 80% of the population.13,14 Abnormal activity of the stellate ganglion has been associated with pain conditions in the head, neck and arms, as well as prolongation of the QT interval and ventricular arrhythmias.7,13,15
Procedures used to interrupt sympathetic activity to the heart include the following: stellate ganglion block with local anesthetics, surgical denervation, thoracic epidural anesthesia and percutaneous radio frequency.10 Even though sympathetic blockade can be achieved through several different modalities, the hemodynamic compromise of RVAs does not always make every option feasible. Some of the procedures require the patient to transfer within the hospital. An anesthesia provider can perform a stellate ganglion block with local anesthetics at the bedside using ultrasound guidance, even when the patient is hemodynamically unstable and unable to transfer for procedures. This block allows for stabilization of the patient, as well as an opportunity to plan a more permanent intervention.12
Stellate ganglion blockade performed during RVAs causes an interruption in the sympathetic fibers to the myocardium, reducing sympathetic outflow and raising the threshold for ventricular arrhythmias. While the stellate ganglion occurs bilaterally, during a RVA a left stellate ganglion block is typically performed due to the dominance of left-sided cardiac sympathetic fibers at the ventricles.16 Chronotropy is not impaired with a left stellate ganglion block because the right stellate ganglion provides compensation.17
While stellate ganglion blockade has been shown to treat RVAs, there is a gap in its use as a standard therapy.18 Given that RVAs have a high mortality rate, even among the inpatient population, a systematic review will provide valuable information on the potential use of a stellate ganglion block with local anesthetic as a method to treat patients with RVA. This review will examine the effectiveness of the use of stellate ganglion blockade treatment in order to determine the success of the procedure, the time period required post block for patient stabilization, mortality measures, and the incidence of RVAs post procedure. A preliminary search of MEDLINE, Embase, JBI Database of Systematic Reviews and Implementation Reports and PubMed was undertaken and no published systematic review protocols nor systematic reviews were identified on this topic.
The review will consider studies that include adults over the age of 18 with ventricular tachycardia or ventricular fibrillation. Any study that includes pediatrics or adults with congenital heart defects will be excluded.
This review will consider studies that evaluate the use of an ultrasound guided stellate ganglion blockade for patients with ventricular tachycardia or ventricular fibrillation refractory to standard treatment with antiarrhythmics and electrical conversion. All studies which have used a local anesthetic and ultrasound guidance will be included. The focus of this review will not include the anesthetic technique for the stellate ganglion block, medications or dosages, therefore they will not be compared.
This review will consider studies that compare the intervention to the ACLS standard of care set by the AHA for ventricular tachycardia or ventricular fibrillation.
This review will consider studies with the primary outcome measure: the incidence of ventricular tachycardia or ventricular fibrillation pre- and post-intervention. Secondary outcomes to be considered will include: adverse effects associated with stellate ganglion blockade, length of time to hospital discharge, and mortality.
Types of studies
This review will consider any experimental study designs including randomized controlled trials, non-randomized controlled trials, quasi-experimental, before and after studies, prospective and retrospective cohort studies, and case-control studies. This review will also consider descriptive observational study designs including case series, individual case reports, and descriptive cross-sectional studies for inclusion.
The search strategy will aim to find both published and unpublished studies. There will be no date limit in the search strategy. Only studies published in English will be searched. An initial limited search of PubMed and Embase will be undertaken followed by analysis of the text words contained in the title and abstract, and of the index terms used to describe the articles. Identified index terms and key words will then be searched across all the databases listed. This informed the development of a search strategy which will be tailored for each information source. A full search strategy for PubMed is detailed in Appendix I. The reference list of all studies selected for critical appraisal will be screened for additional studies.
The databases to be searched include: EMBASE, Web of Science, PubMed.
The trial registers to be searched include: ClinicalTrials.gov and Cochrane Central Register of Controlled Trials. The search for unpublished studies will include: ProQuest Dissertations and Theses and MedNar.
Following the search, all identified citations will be collated and uploaded into Endnote (Clarivate Analytics, PA, USA) and duplicates removed. Titles and abstracts will then be screened by two independent reviewers for assessment against the inclusion criteria for the review. Studies that meet or could potentially meet the inclusion criteria will be retrieved in full and their details imported into Joanna Briggs Institute System for the Unified Management, Assessment and Review of Information (JBI SUMARI). The full text of selected studies will be retrieved and assessed in detail against the inclusion criteria. Full text studies that do not meet the inclusion criteria will be excluded and reasons for exclusion will be provided in an appendix in the final systematic review report. Included studies will undergo a process of critical appraisal. The results of the search will be reported in full in the final report and presented in a PRISMA flow diagram. Any disagreements that arise between the reviewers will be resolved through discussion, or with a third individual.
Assessment of methodological quality
Selected studies will be critically appraised by two independent reviewers at the study level for methodological quality in the review using the standardized critical appraisal instruments, JBI SUMARI.19 Any disagreements that arise will be resolved through discussion, or with a third individual.
Data will be extracted from papers included in the review using the standardized data extraction tool available in JBI SUMARI by two independent reviewers.19 The data extracted will include the incidence of ventricular arrhythmias within 24 hours following stellate ganglion blockade, adverse effects associated with stellate ganglion blockade, and length of time to hospital discharge. Data will also include specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives. Any disagreements that arise between the reviewers will be resolved through discussion, or with a third reviewer. Authors of papers will be contacted to request missing or additional data where required.
Papers will, where possible, be pooled in statistical meta-analysis using JBI SUMARI. Effect sizes will be expressed as either odds ratios (for dichotomous data and weighted (or standardized) mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis Modify as appropriate. Heterogeneity will be assessed statistically using the standard chi-squared and I squared tests. The choice of model (random or fixed effects) and method for meta-analysis will be based on the guidance by Tufunaru et al.20 Subgroup analyses will be conducted where there is sufficient data to investigate. Sensitivity analyses will be conducted to test decisions made regarding. Where statistical pooling is not possible the findings will be presented in narrative form including tables and figures to aid in data presentation, where appropriate.
A funnel plot will be generated to assess publication bias if there are 10 or more studies included in a meta-analysis. Statistical tests for funnel plot asymmetry (Egger test, Begg test, Harbord test) will be performed where appropriate.
Assessing certainty in the findings
A Summary of Findings will be created using GRADEPro GDT software. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach for grading the quality of evidence will be followed. The Summary of Findings will present the following information where appropriate: absolute risks for treatment and control, estimates of relative risk, and a ranking of the quality of the evidence based on study limitations (risk of bias), indirectness, inconsistency, imprecision and publication bias.
The following outcomes will be included in the Summary of Findings: incidence of ventricular arrhythmias 24 hours following stellate ganglion blockade, adverse effects associated with stellate ganglion blockade, length of time to hospital discharge, and amount and type of local anesthetic used in block.
This systematic review is being conducted as partial fulfillment of the requirements for a Doctor of Nursing Practice (DNP) degree, established by Texas Christian University School of Nurse Anesthesia.
Appendix I: Search strategy
1. Elfing M, Razavi M, Massumi A. The evaluation and management of electrical storm
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2011; 38 2:111–121.
2. Sagone A. Electrical storm
: incidence, prognosis and therapy. J Atr Fibrillation
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3. 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 7:742–747.
4. Neumar RW, Otto CW, Link MS, Kronick SL, Shuster M, Callaway CW, et al. Part 8: adult advanced cardiovascular life support: 2010 American Heart Association guidelines from cardiopulmonary resuscitation and emergency cardiovascular care. Circulation
2010; 122 (18 Suppl 3):S729–S767.
5. American Heart Association. Cardiac arrest statistics: statistical update. 2012.
6. Saio FY, Chiu C, Chiu CW, Chen YC, Chen YL, Hsieh YK, et al. Managing cardiac arrest with refractory ventricular fibrillation
in the emergency department: conventional cardiopulmonary resuscitation versus extracorporeal cardiopulmonary resuscitation. Resuscitation
7. Bourke T, Vaseghi M, Michowitz Y, Sankhla V, Shah M, Sapna N, et al. Neuraxial modulation for refractory ventricular arrhythmias
: value of thoracic epidural anesthesia and surgical left cardiac sympathetic denervation. Circulation
2010; 121 21:2255–2262.
8. Gadhinglajkar S, Sreedhar R, Unnikrishnan M, Namboodirir N. Electrical storm
: role of stellate ganglion blockade
and anesthetic implications of left cardiac sympathetic denervation. Indian J Anaesth
2013; 57 4:397–400.
9. Smith DI, Jones C, Morris GK, Kralovic S, Massey HT, Sifian A. Trial ultrasound-guided continuous left stellate ganglion blockade
before surgical gangliolysis in a patient with a left ventricular assist device and intractable ventricular tachycardia
: a pain control application to a complex hemodynamic condition. Asaio J
2015; 61 1:104–106.
10. Hayase J, Vampola S, Acadien F, Narayan SM, Krummen DE. Comparative efficacy of stellate ganglion block with bupivacaine vs pulsed radio frequency in a patient with refractory ventricular arrhythmias
. J Clin Aneth
11. Hall JE, Guyton AC. Guyton and Hall textbook of medical physiology. 13th.Philadelphia, PA: Elsevier; 2016.
12. Tan AY, Abdi S, Buxton AE, Anter E. Percutaneous stellate ganglia block for acute control of refractory ventricular tachycardia
. Heart Rhythm
2012; 9 12:2063–2067.
13. Ali R, Ciccone J, Tseng V. Cervical sympathetic blockade for management of electrical storm
. J Clin Anesth
14. Miller R, Cohen N, Ericksson L, Fleisher L, Wiener-Kronish J, Young M. Miller's anesthesia. 8th.Philadelphia, PA: Elsevier Saunders; 2015.
15. Hardy PA. Extent of sympathetic blockade after stellate ganglion block with bupivacaine. Pain
1989; 36 2:193–196.
16. Schwartz PJ. Cardiac sympathetic denervation to prevent life-threatening arrhythmias. Nat Rev Cardiol
2014; 11 6:346–353.
17. Collura CA, Johnson JN, Moir C, Ackerman MJ. Left cardiac sympathetic denervation for the treatment of long QT syndrome and catecholaminergic polymorphic ventricular tachycardia
using video-assisted thoracic surgery. Heart Rhythm
2009; 6 6:752–759.
18. Malik AA, Khan AA, Dingmann K, Qureshi MH, Thompson M, Suri M, et al. Percutaneous inferior cervical sympathetic ganglion blockade for the treatment of ventricular tachycardia
storm: case report and review of the literature. J Vasc Interv Neurol
2014; 7 5:48–51.
19. The Joanna Briggs Institute. Reviewers’ Manual: 2014 edition. Australia: Joanna Briggs Institute; 2014.
20. Tufanaru C, Munn Z, Stephenson M, Aromataris E. Fixed or random effects meta-analysis? Common methodological issues in systematic reviews of effectiveness. Int J Evid Based Healthc
2015; 13 3:196–207.