Stellate Ganglion Block Success In Recurrent Ventricular Arrhythmias
Overview
One potential treatment for refractory ventricular arrhythmias is a stellate ganglion block (SGB). This study analyzed the effectiveness of SGB based on patient and arrhythmia characteristics, as well as predictors of success. Conducted across multiple centers in the Czech Republic and the United States, the study’s primary outcome was the absence of ventricular arrhythmias 24 hours after SGB. The analysis evaluated SGB efficacy based on factors such as cardiomyopathy etiology, arrhythmia type, side of the SGB, use of inotropes, and mechanical circulatory support. Binary logistic regression was used to identify factors linked to the primary outcome.
Introduction
Ventricular tachycardia (VT) and ventricular fibrillation (VF) are severe cardiac arrhythmias that can lead to sudden cardiac death if not managed promptly. These life-threatening conditions often resist conventional treatments, making their management particularly difficult in acute settings. One promising therapeutic target for the acute treatment of VT/VF involves modulating the sympathetic nervous system, as heightened autonomic tone is known to contribute to the onset and perpetuation of these arrhythmias.
An emerging intervention in this context is the use of percutaneous stellate ganglion block (SGB). SGB functions by temporarily inhibiting sympathetic outflow to the myocardium, thereby reducing the incidence of ventricular arrhythmias. Early studies suggest that SGB can effectively suppress refractory VT/VF in certain patients, offering a potential lifeline for individuals who are unresponsive to other forms of treatment such as antiarrhythmic drugs, cardioversion, or ablation.
Despite its growing use, there is a lack of extensive research on the factors that predict the success of SGB in clinical settings. It remains unclear whether specific patient characteristics, such as the underlying cause of cardiomyopathy or the type of arrhythmia (VT vs. VF), influence the efficacy of SGB. Procedural factors, including the laterality of the block (left vs. right stellate ganglion), as well as the presence of inotropic agents or mechanical circulatory support, may also impact treatment outcomes.
This study aimed to fill this gap by examining a large multicenter cohort of patients treated with SGB for refractory VT/VF in both the Czech Republic and the United States. The primary goal was to assess the effectiveness of SGB in suppressing ventricular arrhythmias within 24 hours of the procedure. Additionally, the study sought to identify clinical and procedural predictors of successful SGB outcomes. These factors included the type and laterality of arrhythmia, the underlying etiology of cardiomyopathy, the use of mechanical support devices such as intra-aortic balloon pumps or extracorporeal membrane oxygenation (ECMO), and the administration of inotropic agents.
By identifying which factors contribute to the success of SGB, this research could help refine the use of SGB in clinical practice, optimizing patient selection and procedural approaches to improve outcomes in those suffering from refractory ventricular arrhythmias. Further studies are encouraged to validate these findings and explore the long-term benefits of SGB in managing life-threatening arrhythmias.
Methods
Inclusion Criteria:
- Age: Participants aged 18 years or older.
- Diagnosis of Refractory Ventricular Arrhythmias (VT/VF): Defined as three or more episodes of VT or VF within 24 hours requiring treatment.
- Failure of Standard Treatments: Patients with VT/VF deemed refractory to a combination of therapies, including antiarrhythmics, beta-blockers, sedation, intubation, and/or ablation.
- Eligibility for Stellate Ganglion Block (SGB): Patients who met the clinical judgment criteria of their primary care team for the administration of SGB.
- Able to Provide Consent: Patients or their legal representatives were able to provide informed consent for the procedure.
Exclusion Criteria:
- Non-refractory VT/VF: Patients experiencing fewer than three VT/VF episodes within 24 hours or those responding to conventional antiarrhythmic therapies.
- Contraindications for SGB: Individuals with central line placement impeding SGB, awake patients without intubation protection, or other medical contraindications for performing the block.
- Incomplete Data: Patients with missing clinical data, telemetry, or procedural notes necessary for outcome analysis.
- Co-existing Neurological or Musculoskeletal Conditions: Conditions that could interfere with the effectiveness or safety of SGB, such as significant cervical spine disease.
- Pregnancy: Pregnant individuals were excluded due to the unknown safety of SGB in this population.
These criteria ensured that only suitable candidates were selected for the study, maximizing the safety and effectiveness of SGB in treating refractory VT/VF.
This study analyzed patients who underwent stellate ganglion block (SGB) for refractory ventricular arrhythmias (VT/VF) between 2016 and 2022 at Duke University Medical Center (USA) and the Institute of Clinical and Experimental Medicine (IKEM) in Prague, Czech Republic. Eligible participants were adults aged 18 and older, experiencing refractory VT/VF, defined as three or more episodes of VT/VF within 24 hours despite treatment. Treatment was deemed refractory when patients failed to respond to a combination of antiarrhythmic drugs, beta-blockers, sedation, or ablation. There were no pre-specified interventions required for SGB eligibility.
SGB procedures were conducted at the bedside with ultrasound guidance, administered by either an anesthesiologist or a cardiologist. At Duke, anesthesiologists primarily performed the procedure, while cardiologists led the procedure at IKEM. During SGB, 8–12 mL of local anesthetic was injected near the stellate ganglion. Bilateral blocks were attempted unless contraindicated, such as the presence of central lines or if the patient was awake without intubation protection. The left side was prioritized for unilateral blocks. For repeat procedures, the same side was blocked if the initial attempt was unilateral, while bilateral blocks were repeated if initially done.
Clinical data collected for analysis included demographic details, comorbidities, VT/VF type and morphology, mechanical circulatory support status, inotrope use, previous ablation procedures, use of antiarrhythmic medications, beta-blocker use and dosage, left ventricular ejection fraction, and serum creatinine levels. The arrhythmia morphology was classified as monomorphic/polymorphic VT or VF, and patients experiencing both VT and VF during their electrical storm were categorized as VF for statistical purposes. Comorbid conditions, such as cardiomyopathy, atrial fibrillation, and acute myocardial infarction, were also documented.
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The primary outcome of interest was the absence of VT/VF within 24 hours after SGB, defined as zero episodes during this time frame. Secondary outcomes included VT/VF event rates and shocks, both implantable cardioverter defibrillator (ICD) and external, before and after the procedure. Event rates were determined through continuous telemetry recordings and interrogation of cardiac implantable electronic devices (CIEDs), with episodes lasting over 30 seconds or requiring shock treatment counted as significant events.
This study builds upon previous analyses of SGB, expanding the evaluation of its effectiveness in reducing VT/VF burden and identifying factors that may predict successful outcomes following the procedure.
Analysis
Initially, non-parametric tests, specifically the Mann-Whitney U test, were employed to compare the number of VT/VF episodes and recorded shocks between cohorts both 24 and 48 hours before and after Stellate Ganglion Block (SGB). These analyses were used to assess outcomes based on various factors, including the etiology of cardiomyopathy and arrhythmia, laterality of the SGB, the use of inotropes, and the presence of mechanical circulatory support (MCS). In addition, rates of repeat SGB injections and in-hospital mortality were analyzed using chi-squared tests.
The next phase of the analysis involved binary logistic regression to identify variables associated with the primary outcomes. Covariates included age, sex, treatment site, the status of implantable cardioverter defibrillator (ICD), ischemic cardiomyopathy (ICM), left ventricular ejection fraction (LVEF), block laterality (unilateral or bilateral), arrhythmia type (VT or VF), and intubation status. Statistical analyses were performed using SPSS software, version 26 (IBM, Armonk, NY).
Results
A total of 117 patients with refractory ventricular tachycardia (VT) or ventricular fibrillation (VF) underwent stellate ganglion block (SGB) treatment. Of these, 41.9% were treated at Duke University, while 58.1% were treated at the Institute of Clinical and Experimental Medicine (IKEM). The patient population was predominantly male (94.0%) and White (87.2%), with 70.1% having an implantable cardioverter-defibrillator (ICD) in place. The average patient age was 63.5 years (SD 11.0), and the mean left ventricular ejection fraction (LVEF) was 26.7% (SD 9.2). Just over half (52.1%) of the patients had ischemic cardiomyopathy (ICM), and monomorphic VT was the most common arrhythmia morphology (70.1%). Additionally, 84.6% of patients were on amiodarone, 53.0% received intravenous lidocaine, 81.2% were using inotropes, and 32.5% were on mechanical circulatory support (MCS), including devices like intra-aortic balloon pumps (IABP), Impella, extracorporeal membrane oxygenation (ECMO), and left ventricular assist devices (LVAD).
The primary analysis revealed a significant reduction in arrhythmia burden following SGB. Prior to SGB, patients experienced a median of 7.5 VT/VF episodes within 24 hours (IQR: 3.0–27.0), which decreased to a median of 1.0 (IQR: 0.0–4.5, P < 0.001) within 24 hours post-SGB. Likewise, defibrillation events reduced from a median of 2.0 (IQR: 0.0–8.0) to 0.0 (IQR: 0.0–1.0, P < 0.001) after SGB. Overall, there was a significant decline in both arrhythmia burden and the need for defibrillations.
In a multivariable analysis, older age was associated with decreased odds of SGB success (OR: 0.96 per year, 95% CI: 0.92–0.99, P = 0.039), while a higher LVEF showed a trend toward better outcomes (OR: 1.05 per % EF, 95% CI: 0.995–1.11, P = 0.077). Notably, patients older than 75 had lower response rates (10%) to SGB. No other significant predictors of SGB success, such as cardiomyopathy type, arrhythmia type, block laterality, inotrope use, MCS, or intubation status, were identified.
Patients with ischemic and non-ischemic cardiomyopathy demonstrated similar positive responses to SGB, with no significant differences in VT/VF events or shocks 24 and 48 hours post-SGB. Additionally, while VF patients experienced more shocks than VT patients before the procedure, both arrhythmia types responded similarly well to SGB, with no significant difference in the number of post-SGB arrhythmia events or in-hospital mortality.
Conclusion
In conclusion, stellate ganglion block (SGB) proved to be an effective intervention in reducing the burden of refractory ventricular tachycardia (VT) and ventricular fibrillation (VF) in a diverse cohort of patients. The treatment led to a significant reduction in the frequency of VT/VF episodes and defibrillation events within 24 hours post-procedure. While older age was associated with decreased odds of SGB success, other factors such as cardiomyopathy type, arrhythmia morphology, block laterality, and the presence of mechanical circulatory support or inotropes did not significantly influence the outcomes. Both ischemic and non-ischemic cardiomyopathy patients, as well as those with VT or VF, responded favorably to SGB, highlighting its potential as a viable option for acute management of refractory arrhythmias. Further research is warranted to explore long-term outcomes and refine patient selection criteria for SGB in refractory VT/VF cases.
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