Bilateral cardiac sympathetic denervation: why, who and when?

A Case Report of Elective Bilateral Proximal Intercostal Blocks Used to Prevent Arrhythmia in Catecholaminergic Polymorphic Ventricular Tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an arrhythmogenic disorder characterized by episodes of polymorphic ventricular tachycardia. Clinically, patients who have CPVT present with juvenile sudden death or stress-induced syncope. We present a case of an 18-year-old girl with CPVT resistant to traditional pharmacotherapies. Instead of a typical stellate ganglion block (SGB), the patient underwent bilateral continuous proximal intercostal blocks that successfully inhibited arrhythmogenic events. This therapeutic method may provide an alternative to SGBs and demonstrates proof of concept for an early elective intervention to be included in the diagnostic and therapeutic algorithm for patients with CPVT.

Bilateral Cardiac Sympathetic Denervation as a Safe Therapeutic Option for Ventricular Arrhythmias

Background

The recurrence of ventricular arrhythmias (VAs) in patients who have already undergone treatment with antiarrhythmic medication, catheter ablation, and the insertion of implantable cardioverter defibrillators is not uncommon. Recent studies have shown that bilateral cardiac sympathetic denervation (BCSD) effectively treats VAs. However, only a limited number of studies have confirmed the safety of BCSD as a viable therapeutic option for VAs.

Methods

This single-center study included 10 patients, who had a median age of 54 years (interquartile range [IQR], 45-65 years) and a median ejection fraction of 58.5% (IQR, 56.2%-60.8%), with VAs who underwent video-assisted BCSD. BCSD was executed as a single-stage surgery for 8 patients, while the remaining 2 patients initially underwent left cardiac sympathetic denervation followed by right cardiac sympathetic denervation. We evaluated postoperative complications, the duration of hospital stays, and VA-related symptoms before and after surgery.

Results

The median hospital stay after surgery was 2 days (IQR, 2-3 days). The median surgical time for BCSD was 113 minutes (IQR, 104-126 minutes). No significant complications occurred during hospitalization or after discharge. During the median follow-up period of 13.5 months (IQR, 10.5-28.0 months) from surgery, no VA-related symptoms were observed in 70% of patients.

Conclusion

The benefits of a short postoperative hospitalization and negligible complications make BCSD a safe, alternative therapeutic option for patients suffering from refractory VAs.

Outcomes Comparison of Robot-Assisted and Video-Assisted Thoracoscopic Cardiac Sympathetic Denervation

OBJECTIVE

Cardiac sympathetic denervation (CSD) is a surgical antiadrenergic procedure that can reduce sustained ventricular tachyarrhythmia (VT). Video-assisted thoracoscopic surgery (VATS) is currently the standard approach used in CSD, and the practicality for robot-assisted thoracoscopic surgery (RATS) has yet to be investigated.

METHODS

We conducted a single-center retrospective study of all adult patients (N = 67) who underwent CSD from 2015 to 2021. We compared short-term outcomes of those treated with RATS versus VATS thoracic sympathectomy. For patients with VT, we examined the effectiveness of a RATS approach in reducing implantable cardioverter defibrillator (ICD) shock burden.

RESULTS

A total of 34 patients underwent RATS cardiac denervation, and 33 underwent VATS cardiac denervation. Those undergoing RATS denervation had a significantly shorter procedure duration with a median of 129 min (P = 0.008). Patients receiving the VATS approach were significantly more complicated by pneumothorax (P = 0.004) and overall complications (P = 0.01) when compared with the RATS approach. At 1 year after surgery, both groups had significant reductions in ICD shocks compared with before surgery, both decreasing from a median of 4 to 0 shocks (P < 0.001). In addition, at 1 year after surgery, the percentage of patients with persistent ICD shocks and the median of ICD shocks were similar between the groups.

CONCLUSIONS

The RATS approach to cardiac denervation has similar 1-year follow-up outcomes in reducing recurrent VT as the VATS approach. However, patients undergoing RATS denervation experienced better perioperative outcomes. This shows promise for robotic CSD to be an effective and safe therapeutic option for patients with malignant arrhythmias.

Bilateral Cardiac Sympathetic Denervation in Patients with Congenital Long QT Syndrome

BACKGROUND

Long QT syndrome (LQTS) is a potentially lethal, yet treatable genetic heart disease for which left cardiac sympathetic denervation (LCSD) is a class I recommendation. Recent reports have suggested bilateral CSD (BiCSD) as the initial surgical denervation therapy in LQTS.

OBJECTIVE

To determine the frequency and settings in which BiCSD was used in a tertiary referral center with expertise in LCSD.

METHODS

We performed retrospective review of 234 LCSD patients/1,638 (14%) LQTS patients who underwent sympathetic denervation at our institution to identify the subset with BiCSD. Cardiac events (CEs) before LCSD, after LCSD, and after completion of BiCSD were recorded and defined as being an appropriate ICD shock, arrhythmic syncope or sudden cardiac arrest.

RESULTS

Only 11 patients (4.7%, 6[55%] females) had BiCSD at our institution. Patients who received BiCSD trended towards being younger at diagnosis (6±15 vs. 14±13 years, p=0.06) and being more likely to be symptomatic (73% vs. 53%, p=0.07) than the larger LCSD-only cohort. Continued CEs post-LCSD (3.8 CEs per patient on average) was the predominant determinant to return for BiCSD. Over 60 combined years of follow-up, 4 patients have not had a post-BiCSD CE, while the other 7 patients average 3.6 non-lethal CEs.

CONCLUSIONS

Less than 5% of all patients receiving denervation therapy underwent BiCSD. When BiCSD was chosen, it was almost always done in a staged sequential manner starting with LCSD first and when driven by the arrhythmogenicity of the LQTS substrate, despite otherwise optimized guideline-directed therapies.

Cardiac Sympathetic Denervation for the Management of Ventricular Arrhythmias

BACKGROUND

The autonomic nervous system contributes to the pathogenesis of ventricular arrhythmias (VA). Though anti-arrhythmic drug therapy and catheter ablation are the mainstay of management of VAs, success may be limited in patients with more refractory arrhythmias. Sympathetic modulation is increasingly recognized as a valuable adjunct tool for managing VAs in patients with structural heart disease and inherited arrhythmias.

RESULTS

In this review, we explore the role of the sympathetic nervous system and rationale for cardiac sympathetic denervation (CSD) in VAs and provide a disease-focused review of the utility of CSD for patients both with and without structural heart disease.

CONCLUSIONS

We conclude that CSD is a reasonable therapeutic option for patients with VA, both with and without structural heart disease. Though not curative, many studies have demonstrated a significant reduction in the burden of VAs for the majority of patients undergoing the procedure. However, in patients with unilateral CSD and subsequent VA recurrence, complete bilateral CSD may provide long-lasting reprieve from VA.

Effectiveness of ultrasonography-guided cardiac sympathetic denervation in acute control of electrical storm: A retrospective case series

Background and Aims

Ultrasonography-guided left cardiac sympathetic denervation (LCSD) or bilateral cardiac sympathetic denervation (BCSD) may be a useful intervention in the electrical storm (ES) that persists despite pharmacological therapy. The aim of our study was to evaluate the effectiveness of ultrasonography-guided LCSD or BCSD in the acute control of ES. We conducted a retrospective case series of patients who underwent ultrasonography-guided CSD for control of ES at a tertiary care hospital.

Material and Methods

Data of all patients who underwent unilateral or bilateral CSD were collected from January 2017 to December 2019. Eleven patients with ES refractory to standard antiarrhythmic therapy underwent ultrasonography-guided pharmacological CSD (eight underwent LCSD and three underwent BCSD). Quantitative data was expressed as mean and median with interquartile range (IQR). Non-quantitative data was expressed in proportions.

Results

Eleven patients underwent ultrasonography-guided pharmacological CSD (eight underwent LCSD and three underwent BCSD). Six of the eleven patients were female (54.5%). Ischemia was the underlying substrate in nine patients (81.8%). Five patients (46%) had complete resolution of ventricular tachycardia (VT) after CSD and one had 90% reduction in episodes of VT. The median follow-up duration was 8 months inter-quartile range IQR (7-18). One patient succumbed to heart failure and one patient was lost to follow up. The other patients had no further events and were well at last follow up.

Conclusion

Ultrasonography-guided pharmacological CSD is effective in the acute control of ES. It is easily performed with equipment that is readily available and relatively safe in terms of immediate complications and is an ideal second-line intervention when ES persists despite drug therapy.

VATS cardiac sympathetic denervation for ventricular arrhythmias: initial experience in a tertiary care centre

Cardiac sympathetic denervation (CSD) is a useful therapeutic option for patients with ventricular arrhythmias (VAs) refractory to anti-arrhythmic agents and/or catheter ablation. However, the experience is mostly limited to non-structural heart disease in paediatric patients. The advent of video-assisted thoracoscopic surgery (VATS) with its reduced morbidity has encouraged the use of VATS CSD in patients with structural heart disease. In this series, we report the surgical and cardiac outcomes of VATS-guided CSD in four patients who presented with electrical storm in the setting of different structural cardiomyopathies. Four patients underwent VATS-guided CSD at our centre during the period 2019-2021 after failure of conventional medical and/or ablative treatment for the management of refractory VAs. All four patients presented with electrical storm with different cardiomyopathies including ischaemic (post-acute myocardial infarction) and non-ischaemic aetiologies (sarcoidosis, non-specific right ventricular cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy). A combined total of 349 implantable cardioverter defibrillator (ICD) shocks were registered in the 4 weeks preceding the procedure with mean shocks of 87 per patient. All four patients successfully underwent CSD through the VATS approach with no operative mortality or any major surgical morbidity. All patients had resolution of electrical storms with 75% of patients remaining free of ICD shocks at a mean follow-up of 14.87 months. One patient who remained free of ICD shocks and recurrent VAs died at 23 months after the procedure due to progressive heart failure and complications. VATS CSD is a safe and effective complementary therapeutic modality in patients with life-threatening refractory VAs and electrical storms irrespective of the underlying substrate.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-022-01361-y.

Bilateral Superior Cervical Sympathectomy Activates Signal Transducer and Activator of Transcription 3 Signal to Alleviate Myocardial Ischemia-Reperfusion Injury

Background

There is growing evidence about the effect of bilateral superior cervical sympathectomy on myocardial ischemia-reperfusion (I/R) injury. Studies have increasingly found that the signal transducer and activator of transcription 3 (STAT3) plays a protective role in myocardial I/R injury. However, the precise mechanism is unknown. The present study explored the bilateral superior cervical sympathectomy’s effect and potential mechanism in mice myocardial I/R injury.

Methods

The left heart I/R injury model was created by ligating the anterior descending branch of the coronary artery for 30 min followed by reperfusion. Bilateral superior cervical sympathectomy was performed before myocardial I/R injury. To evaluate the effect of bilateral superior cervical sympathectomy on the myocardium, we examined the myocardial infarct size and cardiac function. Then, myocardial apoptosis, inflammation, and oxidative stress were detected on the myocardium. Furthermore, the expression of STAT3 signal in myocardial tissue was measured by western blotting. To further examine the cardioprotective effect of STAT3 after bilateral superior cervical sympathectomy, the STAT3 inhibitor (static) was utilized to inhibit the phosphorylation of STAT3.

Results

The results showed that the myocardial I/R injury decreased and the cardiac function recovered in the myocardial I/R injury after cervical sympathectomy. Meanwhile, cervical sympathectomy reduced the myocardial distribution of the sympathetic marker tyrosine hydroxylase (TH) and systemic sympathetic tone. And levels of oxidative stress, inflammatory markers, and apoptosis were reduced in myocardial tissue. We also found that the STAT3 signal was activated in myocardial tissue after cervical sympathectomy. STAT3 inhibitor can partially reverse the myocardial protective effect of cervical sympathectomy.

Conclusion

Bilateral superior cervical sympathectomy significantly alleviated myocardial I/R injury in mice. And activation of the STAT3 signal may play an essential role in this.

Autonomic modulation of ventricular electrical activity: recent developments and clinical implications

PURPOSE

This review aimed to provide a complete overview of the current stance and recent developments in antiarrhythmic neuromodulatory interventions, focusing on lifethreatening vetricular arrhythmias.

METHODS

Both preclinical studies and clinical studies were assessed to highlight the gaps in knowledge that remain to be answered and the necessary steps required to properly translate these strategies to the clinical setting.

RESULTS

Cardiac autonomic imbalance, characterized by chronic sympathoexcitation and parasympathetic withdrawal, destabilizes cardiac electrophysiology and promotes ventricular arrhythmogenesis. Therefore, neuromodulatory interventions that target the sympatho-vagal imbalance have emerged as promising antiarrhythmic strategies. These strategies are aimed at different parts of the cardiac neuraxis and directly or indirectly restore cardiac autonomic tone. These interventions include pharmacological blockade of sympathetic neurotransmitters and neuropeptides, cardiac sympathetic denervation, thoracic epidural anesthesia, and spinal cord and vagal nerve stimulation.

CONCLUSION

Neuromodulatory strategies have repeatedly been demonstrated to be highly effective and very promising anti-arrhythmic therapies. Nevertheless, there is still much room to gain in our understanding of neurocardiac physiology, refining the current neuromodulatory strategic options and elucidating the chronic effects of many of these strategic options.

Autonomic modulation and cardiac arrhythmias: old insights and novel strategies

The autonomic nervous system (ANS) plays a critical role in both health and states of cardiovascular disease. There has been a long-recognized role of the ANS in the pathogenesis of both atrial and ventricular arrhythmias (VAs). This historical understanding has been expanded in the context of evolving insights into the anatomy and physiology of the ANS, including dysfunction of the ANS in cardiovascular disease such as heart failure and myocardial infarction. An expanding armamentarium of therapeutic strategies-both invasive and non-invasive-have brought the potential of ANS modulation to contemporary clinical practice. Here, we summarize the integrative neuro-cardiac anatomy underlying the ANS, review the physiological rationale for autonomic modulation in atrial and VAs, highlight strategies for autonomic modulation, and finally frame future challenges and opportunities for ANS therapeutics.

Bilateral thoracoscopic sympathectomy for cardiac denervation in pediatric population: Does Kuntz nerve cauterization have an impact on success?

INTRODUCTION

Cardiac sympathetic denervation (CSD) is an effective procedure for the treatment of inherited channelopathies. Left CSD has traditionally been recommended as neuromodulation to prevent arrhythmia episodes; however, it is thought that bilateral sympathectomy in combination with Kuntz ablation may have additional effects effective due to the anatomical variability of preganglionic sympathetic fibers. The aim of the study was to share our single-center clinical experience with bilateral thoracoscopic sympathectomy for cardiac denervation in different groups of pediatric patients with malignant arrhythmias.

METHODS

Fourteen patients (seven with CPVT, five with LQTS, one with resistant ventricular tachycardia as a sequela of myocarditis, and one with cardiomyopathy and atrial tachycardia) underwent bilateral thoracoscopic sympathectomy for cardiac denervation.

RESULTS

In all patients, arrhythmia episodes persisted despite medical therapy, and patients with implantable cardioverter-defibrillator received appropriate therapies. The rate of appropriate therapies was 3.25 per year (1-5 per year) in the year before sympathectomy. No major complications related to the procedure were observed in any of the patients. The QTc interval of LQTS patients decreased from 506.2 ± 16.9 ms before the procedure to 476 ± 28.8 ms after the procedure. The mean duration of follow-up after the procedure was 23.3 months (11-47 months). Only two patients received single episodes of therapy 12 and 22 months after CSD, and one patient had arrhythmic events due to noncompliance to medical therapy.

CONCLUSION

Due to the anatomical variability of preganglionic fibers bilateral CSD with Kuntz nerve ablation effective treatment and is a safe option.

Cardiac sympathetic denervation and mental health

BACKGROUND

Bilateral cardiac sympathetic denervation (BCSD) is a surgical treatment for refractory ventricular arrhythmias. Although the procedure has shown efficacy at reducing cardiac arrhythmias, its impact on mental health is unknown. In the current study we examined associations between the BCSD procedure and mental health.

METHODS

10 ventricular arrhythmia patients undergoing BCSD completed assessments of anxiety, depression, and posttraumatic stress symptoms at pre- and post-BCSD time points. Wilcoxon signed rank and Mann-Whitney U tests were used to examine differences in mental health symptoms in the pre- and post-BSCD states. Point biserial correlations were used to explore associations between BCSD response and mental health symptoms.

RESULTS

A significant reduction of anxiety symptoms was observed from pre- to post-BCSD. At the post-BCSD assessment, participants who successfully responded to the BCSD procedure exhibited lower anxiety symptoms compared to non-responders. However, no significant relationships were identified for depressive or PTSD symptoms.

CONCLUSION

The BCSD procedure is associated with reduced anxiety shortly after successful treatment for refractory ventricular arrhythmias in a small sample. Longitudinal surveillance of mental health symptoms after BCSD may be warranted to monitor the impact of this procedure on mental health.

Mechanism of ventricular premature beats elicited by left stellate ganglion stimulation during acute ischaemia of the anterior left ventricle

AIMS

Enhanced sympathetic activity during acute ischaemia is arrhythmogenic, but the underlying mechanism is unknown. During ischaemia, a diastolic current flows from the ischaemic to the non-ischaemic myocardium. This 'injury' current can cause ventricular premature beats (VPBs) originating in the non-ischaemic myocardium, especially during a deeply negative T wave in the ischaemic zone. We reasoned that shortening of repolarization in myocardium adjacent to ischaemic myocardium increases the 'injury' current and causes earlier deeply negative T waves in the ischaemic zone, and re-excitation of the normal myocardium. We tested this hypothesis by activation and repolarization mapping during stimulation of the left stellate ganglion (LSG) during left anterior descending coronary artery (LAD) occlusion.

METHODS AND RESULTS

In nine pigs, five subsequent episodes of acute ischaemia, separated by 20 min of reperfusion, were produced by occlusion of the LAD and 121 epicardial local unipolar electrograms were recorded. During the third occlusion, left stellate ganglion stimulation (LSGS) was initiated after 3 min for a 30-s period, causing a shortening of repolarization in the normal myocardium by about 100 ms. This resulted in more negative T waves in the ischaemic zone and more VPBs than during the second, control, occlusion. Following the decentralization of the LSG (including removal of the right stellate ganglion and bilateral cervical vagotomy), fewer VPBs occurred during ischaemia without LSGS. During LSGS, the number of VPBs was similar to that recorded before decentralization.

CONCLUSION

LSGS, by virtue of shortening of repolarization in the non-ischaemic myocardium by about 100 ms, causes deeply negative T waves in the ischaemic tissue and VPBs originating from the normal tissue adjacent to the ischaemic border.

Neurocardiac regulation: from cardiac mechanisms to novel therapeutic approaches

Cardiac sympathetic overactivity is a well-established contributor to the progression of neurogenic hypertension and heart failure, yet the underlying pathophysiology remains unclear. Recent studies have highlighted the importance of acutely regulated cyclic nucleotides and their effectors in the control of intracellular calcium and exocytosis. Emerging evidence now suggests that a significant component of sympathetic overactivity and enhanced transmission may arise from impaired cyclic nucleotide signalling, resulting from compromised phosphodiesterase activity, as well as alterations in receptor-coupled G-protein activation. In this review, we address some of the key cellular and molecular pathways that contribute to sympathetic overactivity in hypertension and discuss their potential for therapeutic targeting.

Acute hemodynamics of cardiac sympathetic denervation

INTRODUCTION

We aimed to study the immediate hemodynamic effects of thoracoscopic bilateral cardiac sympathetic denervation (CSD) for recurrent ventricular tachycardia (VT) or VT storm.

METHOD

We studied a group of 18 adults who underwent bilateral thoracoscopic CSD; the blood pressure (BP) and Heart Rate (HR) were continuously monitored during the surgery and up to 6 h post-operatively.

RESULTS

Immediately on removal of the sympathetic ganglia, the patients had a drop in both the systolic (110 mm Hg to 95.8 mm Hg, p < 0.001) and diastolic BP (69.4 mm Hg to65 mm Hg, p = 0.007) along with a drop in the HR (81.6 bpm to 61.2 bpm, p < 0.001).At 6 h after CSD, the systolic and diastolic BP did not recover significantly, while there was recovery in HR (61.2 bpm to 66 bpm, p = 0.02). There was no significant difference between those with and without left ventricular (LV) systolic dysfunction.

CONCLUSION

The acute hemodynamic changes during the perioperative period of CSD are significant but not serious. Awareness of this is useful for peri-operative management.

Emergent Phenol Injection of Bilateral Stellate Ganglion for Management of Refractory Malignant Ventricular Arrhythmias

Case series

Patients: Male, 51-year-old • Male, 59-year-old

Final Diagnosis: Ventricular tachycardia (VT)

Symptoms: Cardiac arrest

Medication: —

Clinical Procedure: Ablation

Specialty: Critical Care Medicine

Stellate ganglion stimulation causes spatiotemporal changes in ventricular repolarization in pig

BACKGROUND

Dispersion in ventricular repolarization is relevant for arrhythmogenesis.

OBJECTIVE

The purpose of this study was to determine the spatiotemporal effects of sympathetic stimulation on ventricular repolarization.

METHODS

In 5 anesthetized female open-chest pigs, ventricular repolarization was measured from the anterior, lateral, and posterior walls of the left ventricle (LV) and right ventricle using up to 40 transmural plunge needles (4 electrodes each) before and after left stellate ganglion stimulation (LSGS) and right stellate ganglion stimulation. In addition, LSGS was performed in 3 pigs (2 male, 1 female) before and after verapamil (5-10 mg/h) administration.

RESULTS

LSGS yielded a biphasic response in repolarization in the lateral and posterior walls of the LV, with prolongation at ∼5 seconds (10 ± 1.5 ms) and shortening at 20-30 seconds of stimulation (-28.9 ± 4.4 ms) during a monotonic pressure increase. While the initial prolongation was abolished by verapamil, late shortening was augmented. Sequential transections of the vagal nerve and stellate ganglia augmented repolarization dispersion responses to LSGS in 2 of 5 hearts. An equal pressure increase by aortic occlusion resulted in a homogeneous shortening of repolarization in the LV, and the effects were smaller than those during LSGS. Right stellate stimulation shortened repolarization mainly in the anterior LV wall, but the effects were smaller than those of LSGS.

CONCLUSION

LSGS first prolongs (through the L-type calcium current) and then shortens repolarization. The effect of LSGS was prominent in the posterior and lateral, not the anterior, LV walls.

Efficacy of Stellate Ganglion Blockade in Managing Electrical Storm: A Systematic Review

BACKGROUND

The efficacy of percutaneous stellate ganglion block (SGB) for managing electrical storm (ES) is not well understood.

OBJECTIVE

To characterize the efficacy of SGB as a treatment for ES.

METHODS

We conducted literature searches using PubMed/Medline and Google Scholar, for mixed combinations of terms including "stellate ganglion block", *ganglion block (ade)", "sympathetic block (ade)" and "arrhythmia", "ventricular arrhythmia (VA)" or "tachycardia" (VT), "ventricular fibrillation" (VF), "electrical storm". Inclusion criteria were presentation with guideline-defined ES and treatment with SGB. Exclusion criteria: presentation with any supraventricular arrhythmia, VA without ES, or surgical sympathectomy. Studies lacking basic demographic data, arrhythmia description, and outcomes were excluded.

RESULTS

Of 3,374 publications reviewed, 38 patients from 23 studies met study criteria (52 ± 19.1 years, 11 F, 17 with ischemic cardiomyopathy). Anti-arrhythmics were used in all patients. Mean Left ventricular ejection fraction was 31 ± 10%. ES was triggered by acute myocardial infarction in 15 patients and QT prolongation in 7 patients. The most common local anesthetic used for SGB was bupivacaine (0.25-0.5%). SGB resulted in a significant decrease in VA burden (12.4±8.8 vs. 1.04±2.12 episodes/day, p< 0.001) and number of external and ICD shocks (10.0±9.1 vs. 0.05±0.22 shocks/day, p< 0.01). Following SGB, 80.6% of patients survived to discharge.

CONCLUSION

SGB is an effective acute treatment for ES. However, larger prospective randomized studies are needed to better understand the role of SGB in ES and other VAs.

The Role of Collaboration Between Electrophysiologists and Surgeons in the Management of Complex Arrhythmia Patients

Although the need for surgery in patients with arrhythmias has declined in the past several decades due to the emergence of catheter ablation, there is still room for collaboration between electrophysiologists and surgeons, mainly when managing patients with atrial fibrillation, ventricular tachycardia, and cardiac implantable electronic devices.

Video-assisted thoracoscopic cardiac denervation of refractory ventricular arrhythmias and electrical storms: a single-center series

BACKGROUND

The combined treatment of beta-blockers with ablation and Implanted cardioverter defibrillation therapy, continues to be the mainstay treatment for ventricular arrhythmias (VAs). Despite treatment, some patients remain refractory.  Recent studies have shown success rates using video-assisted thoracoscopic (VATS) cardiac denervation as an effective therapeutic option for these patients.

CASE SERIES PRESENTATION

During a period of three years, from 2015 through 2017, twenty patients (N = 20) failed traditional medical and interventional treatment for the management of ventricular arrhythmias and electrical storms. After remaining refractory, the patients were referred to our thoracic surgery department for a VATS based treatment. The patients all had ventricular arrhythmias and electrical storms secondary to different cardiomyopathies. The patients were refractory to combined medical (beta-blockers), Implanted Cardioverter defibrillation (ICD) and ablation therapy. All twenty patients agreed to surgery and were taken to cardiac denervation using a bilateral VATS approach by two thoracic surgeons at a single Cardiothoracic center. During the month prior to bilateral VATS denervation a combined total of twenty-nine (N = 29) ICD shocks were registered in addition to six (N = 6) cases of electrical storms averaging three (N = 3) shocks per day. Mean shocks per patient was 2.3. During the first three months following VATS, the patients had a 90% (N = 18/20) total resolution of ICD registered shocks, a 100% (N = 6/6) resolution of electrical storms, and a 92% (N = 11/12) resolution of shocks in patients having previous ablation therapy. No complications were documented following surgery except for one case of pneumothorax as a result of the procedure, and there were no peri-operative mortalities.

CONCLUSIONS

Bilateral thoracoscopic cardiac denervation can be a safe and seemingly effective therapeutic option for patients presenting with life-threatening refractory ventricular arrhythmias and electrical storms in a variety of cardiomyopathies including Chagas disease.

Bilateral sympathetic stellate ganglionectomy attenuates myocardial remodelling and fibrosis in a rat model of chronic volume overload

Reducing sympathetic neurohormone expression is a key therapeutic option in attenuating cardiac remodelling. Present study tested the feasibility of attenuating cardiac remodelling through reducing sympathetic neurohormone level by partial cardiac sympathetic denervation in a rat model of chronic volume overload. Male Sprague‐Dawley rats were randomized into sham group (S, n = 7), aortocaval fistula group (AV, n = 7), and aortocaval fistula with bilateral sympathetic stellate ganglionectomy group (AD, n = 8). After 12 weeks, myocardial protein expression of sympathetic neurohormones, including tyrosine hydroxylase, neuropeptide Y, growth associated protein 43, and protein gene product 9.5, were significantly up‐regulated in AV group compared to S group, and down‐regulated in AD group. Cardiac remodelling was aggravated in AV group compared to S group and attenuated in AD group. The myocardial deposition of extracellular matrix, including collagen I and III, was enhanced in AV group, which was reduced in AD group. Myocardial angiotensin II and aldosterone expressions were significantly up‐regulated in AV group and down‐regulated in AD group. Our results show that bilateral sympathetic stellate ganglionectomy could attenuate cardiac remodelling and fibrosis by down‐regulating sympathetic neurohormones expression in this rat model of chronic volume overload.

Catheter Ablation for Ventricular Tachycardia in Patients with Structural Heart Disease

Ventricular tachycardia is a potentially fatal arrhythmia that occurs most frequently in patients with structural heart disease. Acute and long- term management can be complex, requiring an integrated approach with multiple therapeutic modalities including antiarrhythmic drugs, implantable cardioverter defibrillators, and catheter ablation. Each of these options has a role in management of ventricular tachycardia and are generally used in combination. It is essential to be aware that each approach has potential deleterious consequences that must be balanced while establishing a treatment strategy. Catheter ablation for ventricular tachycardia is performed with increasing frequency with rapidly evolving techniques. In this review, we discuss the acute and long-term management of ventricular tachycardia with a focus on techniques and evidence for catheter ablation.

Morphological Spectra of Adult Human Stellate Ganglia: Implications for Thoracic Sympathetic Denervation

Cardiac sympathetic denervation (CSD) to treat ventricular arrhythmias (VAs) requires transection at the middle or lower third of stellate (cervicothoracic) ganglia (SG). However, the morphological appearance of the adult SG and distribution of neuronal somata within it are not well described. To determine the morphology of left and right SG (LSG and RSG) and the distribution of somata within. LSG and RSG (n = 28) from 14 embalmed adult cadavers were dissected intact. Weight, volume, height, morphologic appearance, relationship between C8 and T1 ganglia (which form the SG) were determined, along with histology. Demographics, history of cardiac disease, and cause of death were also reviewed. Mean age of the subjects was 76 ± 13 years, and 5/14 were male. Three distinct morphologies of SG were identified: fusiform-rounded; fusiform-elongated; and bilobed. RSG and LSG did not differ in weight or volume. RSG were longer than LSG (2.05 ± 0.28 cm vs. 1.66 ± 0.47 cm, P = 0.024). Bilobed morphology was most common in RSGs (8/14), while fused, elongated was most common in LSG (8/14). RSGs lacked fused, rounded appearance, while 28.6% of LSG appeared as such. Histologically, one focus of somata was seen in fused rounded ganglia, while fused elongated SG had somata distributed throughout. Bilobed SG demonstrated two foci of somata, with the interconnecting stalk containing sparse somata. SG appears in three major forms and contains varying distributions of somata. Larger studies are warranted to define the relationship between gross anatomy and distribution of neuronal somata to improve the efficacy of CSD in treating VAs. Anat Rec, 301:1244-1250, 2018. © 2018 Wiley Periodicals, Inc.

Inflammation, oxidative stress, and glial cell activation characterize stellate ganglia from humans with electrical storm

BACKGROUND

Neuronal remodeling in human heart disease is not well understood.

METHODS

Stellate ganglia from patients with cardiomyopathy (CMY) and refractory ventricular arrhythmias undergoing cardiac sympathetic denervation (n = 8), and from organ donors with normal hearts (n = 8) collected at the time of organ procurement were compared. Clinical data on all subjects were reviewed. Electron microscopy (EM), histologic, and immunohistochemical assessments of neurotransmitter profiles, glial activation and distribution, and lipofuscin deposition, a marker of oxidative stress, were quantified.

RESULTS

In CMY specimens, lipofuscin deposits were larger, and present in more neurons (26.3% ± 6.3% vs. 16.7% ± 7.6%, P < 0.043), than age-matched controls. EM analysis revealed extensive mitochondrial degeneration in CMY specimens. T cell (CD3+) infiltration was identified in 60% of the CMY samples, with one case having large inflammatory nodules, while none were identified in controls. Myeloperoxidase-immunoreactive neutrophils were also identified at parenchymal sites distinct from inflammatory foci in CMY ganglia, but not in controls. The adrenergic phenotype of pathologic samples revealed a decrease in tyrosine hydroxylase staining intensity compared with controls. Evaluation of cholinergic phenotype by staining for the vesicular acetylcholine transporter revealed a low but comparable number of cholinergic neurons in ganglia from both groups and demonstrated that preganglionic cholinergic innervation was maintained in CMY ganglia. S100 staining (a glial cell marker) demonstrated no differences in glial distribution and relationship to neurons; however, glial activation demonstrated by glial fibrillary acidic protein (GFAP) staining was substantially increased in pathologic specimens compared with controls.

CONCLUSIONS

Stellate ganglia from patients with CMY and arrhythmias demonstrate inflammation, neurochemical remodeling, oxidative stress, and satellite glial cell activation. These changes likely contribute to excessive and dysfunctional efferent sympathetic tone, and provide a rationale for sympathectomy as a treatment for arrhythmias in this population.

FUNDING

This work was made possible by support from NIH grants HL125730 to OAA, GM107949 to DBH, and HL084261 and OT2OD023848 to KS.

Bilateral sympathectomy for treatment of refractory ventricular tachycardia

Ventricular tachycardia (VT) commonly occurs in patients with ischemic or nonischemic cardiomyopathy and requires antiarrhythmic drugs, ablation, or advanced circulatory support. However, life-threatening VT may be refractory to these therapies, and may cause frequent implantable cardioverter defibrillator (ICD) discharges. Left cardiac sympathetic denervation reduces the occurrence of these fatal arrhythmias by inhibiting the sympathetic outflow to the cardiac tissue. We present a 69-year-old man with nonischemic cardiomyopathy, life-threatening VT, and hemodynamic instability with numerous ICD discharges, who remained refractory to antiarrhythmic drug therapy and ablation attempts. He was effectively treated with bilateral cardiac sympathectomy. Six months later, he remained free of VT with no ICD discharges.

Cardiac sympatho-vagal balance and ventricular arrhythmia

A hallmark of cardiovascular disease is cardiac autonomic dysregulation. The phenotype of impaired parasympathetic responsiveness and sympathetic hyperactivity in experimental animal models is also well documented in large scale human studies in the setting of heart failure and myocardial infarction, and is predictive of morbidity and mortality. Despite advances in emergency revascularisation strategies for myocardial infarction, device therapy for heart failure and secondary prevention pharmacotherapies, mortality from malignant ventricular arrhythmia remains high. Patients at highest risk or those with haemodynamically significant ventricular arrhythmia can be treated with catheter ablation and implantable cardioverter defibrillators, but the morbidity and reduction in quality of life due to the burden of ventricular arrhythmia and shock therapy persists. Therefore, future therapies must aim to target the underlying pathophysiology that contributes to the generation of ventricular arrhythmia. This review explores recent advances in mechanistic research in both limbs of the autonomic nervous system and potential avenues for translation into clinical therapy. In addition, we also discuss the relationship of these findings in the context of the reported efficacy of current neuromodulatory strategies in the management of ventricular arrhythmia.

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We review advances in mechanistic research in the cardiac autonomic nervous system.

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This is discussed in relation to neuromodulatory therapy for ventricular arrhythmia.

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Neuromodulation therapies can influence both neurotransmitters and co-transmitters.

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This may therefore improve on conventional medical treatment.

Targeted stellate decentralization: Implications for sympathetic control of ventricular electrophysiology

BACKGROUND

Selective bilateral cervicothoracic sympathectomy has proven to be effective for managing ventricular arrhythmias in the setting of structural heart disease. In the procedure currently used, the caudal portions of both stellate ganglia along with thoracic chain ganglia down to T4 ganglia are removed.

OBJECTIVE

The purpose of this study was to define the relative contributions of the T1-T2 and T3-T4 paravertebral ganglia in modulating ventricular electrical function.

METHODS

In anesthetized vagotomized porcine subjects (n = 8), the heart was exposed via sternotomy along with right and left paravertebral sympathetic ganglia to the T4 level. A 56-electrode epicardial sock was placed over both ventricles to assess epicardial activation-recovery intervals (ARIs) in response to individually stimulating right and left stellate vs T3 paravertebral ganglia. Responses to T3 stimuli were repeated after surgical removal of the caudal portions of stellate ganglia and T2 bilaterally.

RESULTS

In intact preparations, stellate ganglion vs T3 stimuli (4 Hz, 4-ms duration) were titrated to produce equivalent decreases in global ventricular ARIs (right side: 85 ± 6 ms vs 55 ± 10 ms; left side: 24 ± 3 ms vs 17 ± 7 ms). Threshold of stimulus intensity applied to T3 ganglia to achieve threshold was 3 times that of T1 threshold. ARIs in unstimulated states were unaffected by bilateral stellate-T2 ganglion removal. After acute decentralization, T3 stimulation failed to change ARIs.

CONCLUSION

Preganglionic sympathetic efferents arising from the T1-T4 spinal cord that project to the heart transit through stellate ganglia via the paravertebral chain. Thus, T1-T2 surgical excision is sufficient to functionally interrupt central control of peripheral sympathetic efferent activity.

Remodeling of stellate ganglion neurons after spatially targeted myocardial infarction: Neuropeptide and morphologic changes

BACKGROUND

Myocardial infarction (MI) induces remodeling in stellate ganglion neurons (SGNs).

OBJECTIVE

We investigated whether infarct site has any impact on the laterality of morphologic changes or neuropeptide expression in stellate ganglia.

METHODS

Yorkshire pigs underwent left circumflex coronary artery (LCX; n = 6) or right coronary artery (RCA; n = 6) occlusion to create left- and right-sided MI, respectively (control: n = 10). At 5 ± 1 weeks after MI, left and right stellate ganglia (LSG and RSG, respectively) were collected to determine neuronal size, as well as tyrosine hydroxylase (TH) and neuropeptide Y immunoreactivity.

RESULTS

Compared with control, LCX and RCA MIs increased mean neuronal size in the LSG (451 ± 25 vs 650 ± 34 vs 577 ± 55 μm(2), respectively; P = .0012) and RSG (433 ± 22 vs 646 ± 42 vs 530 ± 41 μm(2), respectively; P = .002). TH immunoreactivity was present in the majority of SGNs. Both LCX and RCA MIs were associated with significant decreases in the percentage of TH-negative SGNs, from 2.58% ± 0.2% in controls to 1.26% ± 0.3% and 0.7% ± 0.3% in animals with LCX and RCA MI, respectively, for LSG (P = .001) and from 3.02% ± 0.4% in controls to 1.36% ± 0.3% and 0.68% ± 0.2% in LCX and RCA MI, respectively, for RSG (P = .002). Both TH-negative and TH-positive neurons increased in size after LCX and RCA MI. Neuropeptide Y immunoreactivity was also increased significantly by LCX and RCA MI in both ganglia.

CONCLUSION

Left- and right-sided MIs equally induced morphologic and neurochemical changes in LSG and RSG neurons, independent of infarct site. These data indicate that afferent signals transduced after MI result in bilateral changes and provide a rationale for bilateral interventions targeting the sympathetic chain for arrhythmia modulation.

Neuraxial modulation for treatment of VT storm

In the hyperadrenergic state of VT storm where shocks are psychologically and physiologically traumatizing, suppression of sympathetic outflow from the organ level of the heart up to higher braincenters plays a significant role in reducing the propensity for VT recurrence. The autonomic nervous system continuously receives input from the heart (afferent signaling), integrates them, and sends efferent signals to modify or maintain cardiac function and arrhythmogenesis. Spinal anesthesia with thoracic epidural infusion of bupivicaine and surgical removal of the sympathetic chain including the stellate ganglion has been shown to decrease recurrences of VT. Excess sympathetic outflow with catecholamine release can be modified with catheter-based renal denervation. The insights provided from animal experiments and in patients that are refractory to conventional therapy have significantly improved our working understanding of the heart as an end organ in the autonomic nervous system.

Myocardial repolarization dispersion and autonomic nerve activity in a canine experimental acute myocardial infarction model

BACKGROUND

Evidence from a canine experimental acute myocardial infarction (MI) model shows that until the seventh week after MI, the relationship between stellate ganglion nerve activity (SGNA) and vagal nerve activity (VNA) progressively increases.

OBJECTIVE

The purpose of this study was to evaluate how autonomic nervous system activity influences temporal myocardial repolarization dispersion at this period.

METHODS

We analyzed autonomic nerve activity as well as QT and RR variability from recordings previously obtained in nine dogs. From a total of 48 short-term ECG segments, 24 recorded before and 24 recorded 7 weeks after experimentally-induced MI, we obtained three indices of temporal myocardial repolarization dispersion: QTe (from Q-wave to T-wave end), QTp (from Q-wave to T-wave peak), and Te (from T-wave peak to T-wave end) variability index (QTeVI, QTpVI, TeVI). We also performed heart rate variability power spectral analysis on the same segments.

RESULTS

After MI, all the QT variables increased QTeVI (median [interquartile range]) (from -1.76[0.82] to -1.32[0.68]), QTeVI (from -1.90[1.01] to -1.45[0.78]), and TeVI (from -0.72[0.67] to -0.22[1.00]), whereas all RR spectral indices decreased (P <.001 for all). Distinct circadian rhythms in QTeVI (P <.05,) QTpVI (P <.001) and TeVI (P <.05) appeared after MI with circadian variations resembling that of SGNA/VNA. The morning QTpVI and TeVI acrophases approached the SGNA/VNA acrophase. Conversely, the evening QTeVI acrophase coincided with another SGNA/VNA peak. After MI, regression analysis detected a positive relationship between SGNA/VNA and TeVI (R(2): 0.077; β: 0.278; p< 0.001).

CONCLUSION

Temporal myocardial repolarization dispersion shows a circadian variation after MI reaching its peak at a time when sympathetic is highest and vagal activity lowest.