Cardiac sympathectomy for the management of ventricular arrhythmias refractory to catheter ablation

The role of cardiac sympathetic denervation for ventricular arrhythmias: an updated systematic review and meta-analysis

INTRODUCTION

The role of the sympathetic nervous system in the initiation and continuation of ventricular tachyarrhythmias (VTA) is well established. However, whether CSD reduces implantable cardioverter-defibrillator (ICD) shocks and recurrent VTA is still uncertain.

METHODS

A comprehensive literature search was performed at Medline and Embase until March 2023. The primary outcome was the rate of ICD shocks and VTA per patient-year in our pooled analysis of all included articles. Analyses were conducted using Comprehensive Meta-Analysis software.

RESULTS

Initial search yielded 1324 scientific studies with a total of 15 studies fitting our inclusion criteria. ICD shocks at 1 year post-CSD revealed an event rate of 69.8% (95% CI, 56.4-80.4% with 50% heterogeneity) (I2 statistic). ICD shocks at 6 months had an event rate of 59.1% (95% CI, 46.9-70.4%; 47 I2). Analysis of our pooled studies showed that 64.3% of individuals achieved freedom from VTA at 1 year post-CSD (95% CI, 42.3-81.5%; 26% I2), while 62.3% were free from recurrent VTA 6 months post-CSD (95% CI, 51.2-72.2%; 40% I2). Time to mortality directly caused by recurrent VTA post-CSD was subdivided into short-term (0-30 days), intermediate-term (31-364 days), and long-term (≥ 365). Mortality for the short-term tertile was 8.9% (95% CI, 5.0-15.4%; 0% I2), medium-term was 5.3% (95% CI, 2.4-11.3%; 0% I2), and long-term 5.2% (95% CI, 2.4-10.9%; 0% I2).

CONCLUSION

CSD seems to be promising as an acceptable treatment strategy for recurrent VTA refractory to traditional pharmacological or ablation therapy.

Cardiac Sympathetic Denervation as a Treatment for Ventricular Arrhythmias Refractory to Conventional Treatment: A Case Series

Background

Ventricular arrhythmias are a leading cause of sudden death. The objective of this study was to characterise the results of patients with ventricular arrhythmias refractory to standard medical management, undergoing Video-assisted thoracoscopic cardiac sympathetic denervation (VAT-CSD) during 2012-2022 in Cali, Colombia.

Methods

This was an observational retrospective study, using the Institutional General Thoracic Surgery Database for patient identification and retrospectively reviewing the clinical charts for data description and analysis.

Results

Clinical records of 19 patients who underwent VAT-CSD for ventricular arrhythmia were analysed. The patients were predominantly male (73.7%) with an mean age of 62 years. Ischaemic heart disease was the main underlying condition (52.6%); all individuals had a diagnosis of heart failure, with comorbidities such as hypertension (63.1%), acute MI (57.8%) and diabetes (26.3%) also present. The procedure was performed bilaterally in 89.4% of cases and was successful with minimal perioperative complications. Postoperative follow-up showed improvement in symptoms, including a significant reduction in the number of ICD shocks and emergency department visits.

Conclusion

VAT-CSD is a viable, safe and palliative therapeutic option for patients with ventricular arrhythmias who have not responded to conventional treatments, achieving a significant decrease in symptoms with low mortality and perioperative complications.

Ryanodine receptor 2 inhibition reduces dispersion of cardiac repolarization, improves contractile function, and prevents sudden arrhythmic death in failing hearts

Sudden cardiac death (SCD) from ventricular tachycardia/fibrillation (VT/VF) is a leading cause of death, but current therapies are limited. Despite extensive research on drugs targeting sarcolemmal ion channels, none have proven sufficiently effective for preventing SCD. Sarcoplasmic ryanodine receptor 2 (RyR2) Ca2+ release channels, the downstream effectors of sarcolemmal ion channels, are underexplored in this context. Recent evidence implicates reactive oxygen species (ROS)-mediated oxidation and hyperactivity of RyR2s in the pathophysiology of SCD. We tested the hypothesis that RyR2 inhibition of failing arrhythmogenic hearts reduces sarcoplasmic Ca2+ leak and repolarization lability, mitigates VT/VF/SCD and improves contractile function. We used a guinea pig model that replicates key clinical aspects of human nonischemic HF, such as a prolonged QT interval, a high prevalence of spontaneous arrhythmic SCD, and profound Ca2+ leak via a hyperactive RyR2. HF animals were randomized to receive dantrolene (DS) or placebo in early or chronic HF. We assessed the incidence of VT/VF and SCD (primary outcome), ECG heart rate and QT variability, echocardiographic left ventricular (LV) structure and function, immunohistochemical LV fibrosis, and sarcoplasmic RyR2 oxidation. DS treatment prevented VT/VF and SCD by decreasing dispersion of repolarization and ventricular arrhythmias. Compared to placebo, DS lowered resting heart rate, preserved chronotropic competency during transient β-adrenergic challenge, and improved heart rate variability and cardiac function. Inhibition of RyR2 hyperactivity with dantrolene mitigates the vicious cycle of sarcoplasmic Ca2+ leak-induced increases in diastolic Ca2+ and ROS-mediated RyR2 oxidation, thereby reducing repolarization lability and protecting against VT/VF/SCD. Moreover, the consequent increase in sarcoplasmic Ca2+ load improves contractile function. These potentially life-saving effects of RyR2 inhibition warrant further investigation, such as clinical studies of repurposing dantrolene as a potential new therapy for heart failure and/or SCD.

Cardiac sympathetic denervation prevents sudden cardiac arrest and improves cardiac function by enhancing mitochondrial-antioxidant capacity

RATIONALE

Sudden cardiac arrest (SCA) and heart failure (HF) are leading causes of death. The underlying mechanisms are incompletely understood, limiting the design of new therapies. Whereas most autonomic modulation therapies have not shown clear benefit in HF patients, growing evidence indicates cardiac sympathetic denervation (CSD) exerts cardioprotective effects. The underlying molecular and cellular mechanisms remain unexplored.

OBJECTIVE

Based on the hypothesis that mitochondrial reactive oxygen species (mROS) drive the pathogenesis of HF and SCA, we investigated whether CSD prevents SCA and HF by improving mitochondrial antioxidant capacity and redox balance, to correct impaired Ca2+ handling and repolarization reserve.

METHODS AND RESULTS

We interrogated CSD-specific responses in pressure-overload HF models with spontaneous SCA using in vivo echocardiographic and electrocardiographic studies and in vitro biochemical and functional studies including ratiometric measures of mROS, Ca2+ and sarcomere dynamics in left ventricular myocytes. Pressure-overloaded HF reduced mitochondrial antioxidant capacity and increased mROS, which impaired β-adrenergic signaling and caused SR Ca2+ leak, reducing SR Ca2+ and increasing diastolic Ca2+, impaired myofilament contraction and further increased the sympathetic stress response. CSD improved contractile function and mitigated mROS-mediated diastolic Ca2+ overload, dispersion of repolarization, triggered activity and SCA by upregulating mitochondrial antioxidant and NADPH-producing enzymes.

CONCLUSIONS

Our findings support a fundamental role of sympathetic stress-induced downregulation of mROS scavenging enzymes and RyR-leak mediated diastolic Ca2+ overload in HF and SCA pathogenesis that are mitigated by CSD. This first report on the molecular and cellular mechanisms of CSD supports its evaluation in additional high-risk patient groups.

Ryanodine receptor 2 inhibition reduces dispersion of cardiac repolarization, improves contractile function and prevents sudden arrhythmic death in failing hearts

Introduction

Sudden cardiac death (SCD) from ventricular tachycardia/fibrillation (VT/VF) are a leading cause of death, but current therapies are limited. Despite extensive research on drugs targeting sarcolemmal ion channels, none have proven sufficiently effective for preventing SCD. Sarcoplasmic ryanodine receptor 2 (RyR2) Ca 2+ release channels, the downstream effectors of sarcolemmal ion channels, are underexplored in this context. Recent evidence implicates reactive oxygen species (ROS)- mediated oxidation and hyperactivity of RyR2s in the pathophysiology of SCD.

Objective

To test the hypothesis that RyR2 inhibition of failing arrhythmogenic hearts reduces sarcoplasmic Ca 2+ leak and repolarization lability, mitigates VT/VF/SCD and improves contractile function.

Methods

We used a guinea pig model that replicates key clinical aspects of human nonischemic HF, such as a prolonged QT interval, a high prevalence of spontaneous arrhythmic SCD, and profound Ca 2+ leak via a hyperactive RyR2. HF animals were randomized to receive dantrolene (DS) or placebo in early or chronic HF. We assessed the incidence of VT/VF and SCD (primary outcome), ECG heart rate and QT variability, echocardiographic left ventricular (LV) structure and function, immunohistochemical LV fibrosis, and sarcoplasmic RyR2 oxidation.

Results

DS treatment prevented VT/VF and SCD by decreasing dispersion of repolarization and ventricular arrhythmias. Compared to placebo, DS lowered resting heart rate, preserved chronotropic competency during transient β-adrenergic challenge, and improved heart rate variability and cardiac function.

Conclusion

Inhibition of RyR2 hyperactivity with dantrolene mitigates the vicious cycle of sarcoplasmic Ca 2+ leak-induced increases in diastolic Ca 2+ and ROS-mediated RyR2 oxidation, thereby increasing repolarization lability and protecting against VT/VF/SCD. Moreover, the consequent increase in sarcoplasmic Ca 2+ load improves contractile function. These potentially life-saving effects of RyR2 inhibition warrant further investigation, such as clinical studies of repurposing dantrolene as a potential new therapy for heart failure and/or SCD.

Neuromodulation for the Treatment of Refractory Ventricular Arrhythmias

BACKGROUND

Neuromodulation is increasingly recognized as a therapeutic strategy for patients with refractory ventricular arrhythmias (VAs). Percutaneous stellate ganglion blockade (SGB), transcutaneous magnetic stimulation (TcMS), and surgical cardiac sympathetic denervation (CSD) have all been utilized in this setting.

OBJECTIVES

This study sought to characterize contemporary use and outcomes of these neuromodulation techniques for patients with refractory VA.

METHODS

This retrospective cohort study included all patients at the Hospital of the University of Pennsylvania with antiarrhythmic drug (AAD)-refractory VA from 2019 to 2021 who were treated with SGB, TcMS, or CSD.

RESULTS

A total of 34 patients (age 61 ± 14 years, 15 polymorphic VAs [44%], refractory to 1.8 ± 0.8 AADs) met inclusion criteria. SGB was performed on 11 patients (32%), TcMS on 19 (56%), and CSD on 7 (21%). Neuromodulation was associated with a reduction in the number of episodes of sustained VAs from 7 [IQR: 4-12] episodes in the 24 hours before the initial neuromodulation strategy to 0 [IQR: 0-1] episodes in the subsequent 24 hours (P < 0.001). During 1.2 ± 1.1 years of follow-up, 21 (62%) experienced recurrent VAs, and among those patients, the median time to recurrence was 3 [IQR: 1-25] days. Outcomes were similar among patients with monomorphic and polymorphic VAs. Among patients who had an acute myocardial infarction within 30 days before neuromodulation, the burden of VAs decreased from 11 [IQR: 7-12] episodes to 0 episodes in the 24 hours after treatment.

CONCLUSIONS

Autonomic neuromodulation with SGB, TcMS, or CSD in patients with AAD-refractory VAs is safe and results in substantial acute reduction of VA although recurrent arrhythmias are common, and not all patients experience a reduction in arrhythmia burden.

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.

Cardiac sympathetic denervation for untreatable ventricular tachycardia in structural heart disease. Strengths and pitfalls of evolving surgical techniques

Cardiac sympathetic denervation (CSD) is a valuable option in the setting of refractory ventricular arrhythmias in patient with structural heart disease. Since the procedure was introduced for non structural heart disease patients the techniques evolved and were modified to be adopted in several settings. In this state-of-the-art article we revised different techniques, their rationale, strengths, and pitfalls.

Bilateral Thoracoscopic Sympathectomy after Sternotomy for Left Ventricular Assist Device Insertion

Our case is a 73-year-old male with persistent ventricular tachycardia (VT) leading to recent syncopal episodes despite VT ablation and multiple stellate ganglion blocks, frequent hospital admissions, and acute on chronic congestive heart failure requiring intra-aortic balloon pump. The decision was made to proceed with left ventricular assist device placement and bilateral sympathectomies simultaneously. After performing the sternotomy and widely opening bilateral pleural spaces, the lower third of the stellate ganglia to the level of T4 was removed using a combination of the thoracoscope with the sternotomy incision. The use of thoracoscopy greatly assisted with visualization during the sympathectomy.

Ventricular arrhythmia management in patients with genetic cardiomyopathies

Genetic cardiomyopathies are associated with increased risk for cardiac arrhythmias and sudden cardiac death. The management of ventricular arrhythmias (VAs) in patients with these conditions can be nuanced due to particular disease-based considerations, yet data specifically addressing management in these patients are limited. Here we describe the current evidence-based approach to the management of ventricular rhythm disorders in patients with genetic forms of cardiomyopathy, namely, hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, left ventricular noncompaction, and Brugada syndrome, including recommendations from consensus guideline statements when available.

Perioperative management of patients with arrhythmogenic syndromes refractory to medical treatment: A clinical case report

Family heart diseases related to sudden death are a group of cardiovascular diseases (cardiomyopathies, channelopathies, aortic diseases …) that require familiarity of the anesthesiologist with the perioperative treatment of complex hemodynamic disorders, as well as their surgical treatment.¹ We present the case of a 12-year-old man diagnosed with non-obstructive hypertrophic cardiomyopathy (MHNO), after cardiorespiratory arrest (PCR), who underwent video-guided thoracoscopy-guided left sympathectomy (VATS) for frequent syncope, despite pharmacological treatment and implantation of an implantable automatic defibrillator (ICD). Whenever arrhythmic syncope occurs in the setting of familial heart disease, left heart denervation should be considered as the next step in the treatment plan.².

Perioperative management of patients with arrhythmogenic syndromes refractory to medical treatment: A clinical case report

Family heart diseases related to sudden death are a group of cardiovascular diseases (cardiomyopathies, channelopathies, aortic diseases...) that require familiarity of the anesthesiologist with the perioperative treatment of complex hemodynamic disorders, as well as their surgical treatment¹. We present the case of a 12-year-old man diagnosed with non-obstructive hypertrophic cardiomyopathy, after cardiorespiratory arrest, who underwent video-guided thoracoscopy-guided left sympathectomy for frequent syncope, despite pharmacological treatment and implantation of an implantable automatic defibrillator. Whenever arrhythmic syncope occurs in the setting of familial heart disease, left heart denervation should be considered as the next step in the treatment plan².

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.

Surgical Cardiac Sympathetic Denervation for Ventricular Arrhythmias: A Systematic Review

Ventricular arrhythmias are potentially life-threatening disorders that are commonly treated with medications, catheter ablation and implantable cardioverter defibrillator (ICD). Adult patients who continue to be symptomatic, with frequent ventricular arrhythmia cardiac events or defibrillation from ICD despite medical treatment, are a challenging subgroup to manage. Surgical cardiac sympathetic denervation has emerged as a possible treatment option for people refractory to less invasive medical options. Recent treatment guidelines have recommendedcardiac sympathectomy for ventricular tachycardia (VT) or VT/fibrillation storm refractory to antiarrhythmic medications, long QT syndrome, and catecholaminergic polymorphic VT, with much of the data pertaining to pediatric literature. However, for the adult population, the disease indications, complications, and risks of cardiac sympathectomy are less understood, as are the most effective surgical cardiac denervation techniques for this patient demographic. This systematic review navigates available literature evaluating surgical denervation disease state indications, techniques, and sympathectomy risks for medically refractory ventricular arrhythmia in the adult patient population.

Long-Term Outcomes of Bilateral Cardiac Sympathetic Denervation for Refractory Ventricular Tachycardia

OBJECTIVES

This study sought to explore the long-term arrhythmic outcomes of bilateral cardiac sympathetic denervation (BCSD).

BACKGROUND

BCSD has been associated with improved arrhythmic outcomes in patients with refractory ventricular arrhythmias. However, whether BCSD antiarrhythmic effects are sustained long after the procedure is still uncertain.

METHODS

We included consecutive patients who underwent BCSD because of refractory ventricular tachycardia (VT) and had at least 18 months of follow-up. VT recurrence after BCSD was evaluated to assess arrhythmic outcomes. The occurrence of VT episodes within the first 12 weeks after the procedure was assessed to explore the impact of early VT recurrence on late arrhythmia-free survival.

RESULTS

Twenty patients (42 ± 16 years; 55% male) were included in the analysis. Nineteen (95%) patients had structural heart disease (left ventricular ejection fraction: 0.46 ± 0.14). Class I or class III drugs failed for all patients, and the mean number of VT ablation procedures was 2.5 ± 1.6. Over a mean follow-up of 1,300 ± 321 days (median: 1,276 days [Interquartile range (IQR): 1,181 to 1,480 days), 11 (55%) patients remained VT free after sympathectomy. Freedom from sustained VT or implantable cardioverter-defibrillator shock was 60% (95% confidence interval: 0.35 to 0.77) and 54.5% (95% confidence interval: 0.31 to 0.73) after BCSD at 1 and 4 years. Early VT recurrence was not associated with worse late arrhythmia-free survival rates.

CONCLUSIONS

BCSD was associated with longstanding antiarrhythmic effects in patients with refractory ventricular arrhythmias. The occurrence of VT episodes early after the procedure was not associated with worse late arrhythmic outcomes.

Limited Left Thoracoscopic Sympathectomy Effectively Silences Refractory Electrical Storm

BACKGROUND

Electrical Storm is a life-threatening condition that affects up to 20% of patients with ICDs. In this small retrospective study, we report our results with left video-assisted thoracoscopic sympathectomy/ganglionectomy (VATSG) to treat refractory electrical storm in low ejection fraction patients who were not candidates for catheter ablations (CA).

METHODS

We identified 12 patients who presented with electrical storm and underwent a total of 14 video assisted thoracoscopic sympathectomy/ganglionectomy, including three patients on venoarterial extracorporeal membrane oxygenation (VA ECMO). We reviewed demographic data, survival to discharge, number of cardioversions (before and after VATSG), need for readmissions, and need for right-sided procedures.

RESULTS

In the 30 days prior to a left VATSG the mean number of shocks was 22.67 for all patients. For the patients who survived to discharge the mean was 3.55 since surgery with a median of zero shocks after a median follow up of 358 days. Six patients have not experienced any further cardioversions since their last VATSG and five have never been readmitted for VT. Two patients had staged bilateral procedures due to recurrences and of those, one never required any further cardioversions.

CONCLUSIONS

Limited left VATSG is an appropriate and effective initial treatment for ES patients who are not candidates for CA, including patients on VA ECMO for hemodynamic support.

Arrhythmic Risk Profile and Outcomes of Patients Undergoing Cardiac Sympathetic Denervation for Recurrent Monomorphic Ventricular Tachycardia After Ablation

Background

Cardiac sympathetic denervation (CSD) has been used as a bailout strategy for refractory ventricular tachycardia (VT). Risk of VT recurrence in patients with scar‐related monomorphic VT referred for CSD and the extent to which CSD can modify this risk is unknown. We aimed to quantify arrhythmia recurrence risk and impact of CSD in this population.

Methods and Results

Adjusted competing risk time to event models were developed to adjust for risk of VT recurrence and sustained VT/implantable cardioverter–defibrillator shocks after VT ablation based on patient comorbidities at the time of VT ablation. Adjusted VT and implantable cardioverter–defibrillator shock recurrence rates were estimated for the subgroup who subsequently required CSD after ablation. The expected adjusted recurrence rates were then compared with the observed rates after CSD. Data from 381 patients with scar‐mediated monomorphic VT who underwent VT ablation were analyzed, excluding patients with polymorphic VT. Sixty eight patients underwent CSD for recurrent VT. CSD reduced the expected adjusted VT recurrence rate by 36% (expected rate of 5.61 versus observed rate of 3.58 per 100 person‐months, P=0.01) and the sustained VT/implantable cardioverter–defibrillator shock rates by 34% (expected rate of 4.34 versus observed 2.85 per 100 person‐months, P=0.03). The median number of sustained VT/implantable cardioverter–defibrillator shocks in the year before versus the year after CSD was reduced by 90% (10 versus 1, P<0.0001).

Conclusions

Patients referred for CSD for refractory scar‐mediated monomorphic VT are at a higher risk of VT recurrence after ablation as compared with those not requiring CSD, mostly because of their cardiac comorbidities. CSD significantly reduced both the expected risk of recurrences and VT burden.

Stellate Ganglion Blockade With Continuous Infusion Versus Single Injection for Treatment of Ventricular Arrhythmia Storm

OBJECTIVES

This study sought to compare the efficacy and safety of single-injection stellate ganglion block (SGB) with a novel continuous-infusion SGB procedure.

BACKGROUND

SGB for ventricular arrhythmia (VA) storm is typically performed with a single injection of local anesthetic agents.

METHODS

Eighteen patients underwent left-sided SGB (9 single injection and 9 continuous infusion). The number of implantable cardioverter-defibrillator therapies and sustained VAs/24 h were compared between the pre-SGB and post-SGB periods. Adverse effects of SGB and in-hospital outcomes were also compared.

RESULTS

The mean age was 61.1 ± 13.7 years. The presenting arrhythmia was ventricular tachycardia in 13 (72%) patients, ventricular fibrillation in 4 (22%), and both in 1 (6%). Single-injection SGB reduced VA/24 h by a median of 0.3 (interquartile range: 0.2 to 0.9), which was a 45% reduction (p = 0.008), resulting in 5 of 9 patients with no recurrent VA. Continuous-infusion SGB reduced VA/24 h by a median of 2.0 (interquartile range: 1.3 to 3.0), which was a 94% reduction (p = 0.004), resulting in 7 of 9 patients with no recurrent VA (p = 0.006 for comparison with single injection). Transient left arm weakness and voice hoarseness were each noted in 1 patient in both groups. Repeat SGB was required in 4 (44%) patients in the single-injection group. In-hospital outcomes were similar between the groups.

CONCLUSIONS

In patients with VA storm, SGB performed via both continuous-infusion and single-injection approaches provided significant reductions in VA burden. Compared to single-injection SGB, continuous-infusion was associated with a greater reduction in VA burden and similar adverse events, without the need for repeat procedures.

Outcome of a Modified Sympathicotomy for Cardiac Neuromodulation of Untreatable Ventricular Tachycardia

OBJECTIVES

This study aimed to describe the preliminary results of a modified sympathicotomy for cardiac sympathetic denervation (CSD), which may reduce the predictive risk and intraoperative surgical time of the procedure.

BACKGROUND

CSD, in patients with refractory ventricular tachycardia (VT), is comprehensively recognized as an important treatment option for patients with structural heart disease as well as congenital inherited arrhythmia syndrome.

METHODS

We consecutively enrolled 5 patients with refractory VT. Baseline demographic, medical, and surgical data as well as arrhythmia outcomes and procedural complications were evaluated.

RESULTS

A total of 5 patients (mean age: 67.4 years) were enrolled for the treatment of refractory VT with a modified CSD technique. In 3 of 5 patients, an overall reduction in VT burden (ranging from 75% to 100%) and VT number was observed after the CSD despite an in-hospital early recurrence.

CONCLUSIONS

A modified CSD (sympathicotomy T2-T5) with stellate ganglion sparing and the use of unipolar radiofrequency is feasible, effective, and safe in the setting of untreatable VT.

Renal Denervation for the Management of Refractory Ventricular Arrhythmias: A Systematic Review

OBJECTIVES

The authors performed a systematic review and meta-analysis to determine the efficacy of renal denervation (RDN) in patients with refractory ventricular arrhythmias (VA) or electrical storm (ES).

BACKGROUND

Although catheter ablation is efficacious for the treatment of structural heart disease ventricular tachycardia (VT), there are proportion of patients who have refractory VT despite multiple procedures. In this setting, novel adjunctive therapies such as renal denervation have been performed.

METHODS

A systematic review of published data was performed. Studies that evaluated patients undergoing RDN for VA or ES were included. Outcome measures of VA, sudden cardiac death, ES, or device therapy were required. Case reports, editorials, and conference presentations were excluded. Random effects meta-analysis was conducted to explore change or final mean values in the study outcomes.

RESULTS

A total of 328 articles were identified by the literature search. Seven studies met the eligibility criteria and were included in the systematic review, with a total of 121 pooled patients. The weighted mean age was 63.8 ± 13.1 years, ejection fraction 30.5 ± 10.3%, 76% were men, 99% were on a beta blocker, 79% were on amiodarone, 46% had previously undergone catheter ablation, and 8.3% had previously undergone cardiac sympathetic denervation. Meta-analysis demonstrated a significant effect of RDN in reducing implantable cardiac defibrillator therapies, with a standardized mean difference (SMD) of -3.11 (p < 0.001). RDN also reduced the number of VA episodes (SMD -2.13; p < 0.001), antitachycardia pacing episodes (SMD -2.82; p = 0.002), and shocks (SMD -2.82; p = 0.002).

CONCLUSIONS

RDN is an effective treatment for refractory VAs and ES, although randomized data are lacking.

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.

Autonomic Modulation of Cardiac Arrhythmias: Methods to Assess Treatment and Outcomes

The autonomic nervous system plays a central role in the pathogenesis of multiple cardiac arrhythmias, including atrial fibrillation and ventricular tachycardia. As such, autonomic modulation represents an attractive therapeutic approach in these conditions. Notably, autonomic modulation exploits the plasticity of the neural tissue to induce neural remodeling and thus obtain therapeutic benefit. Different forms of autonomic modulation include vagus nerve stimulation, tragus stimulation, renal denervation, baroreceptor activation therapy, and cardiac sympathetic denervation. This review seeks to highlight these autonomic modulation therapeutic modalities, which have shown promise in early preclinical and clinical trials and represent exciting alternatives to standard arrhythmia treatment. We also present an overview of the various methods used to assess autonomic tone, including heart rate variability, skin sympathetic nerve activity, and alternans, which can be used as surrogate markers and predictors of the treatment effect. Although the use of autonomic modulation to treat cardiac arrhythmias is supported by strong preclinical data and preliminary studies in humans, in light of the disappointing results of a number of recent randomized clinical trials of autonomic modulation therapies in heart failure, the need for optimization of the stimulation parameters and rigorous patient selection based on appropriate biomarkers cannot be overemphasized.

Cardiac sympathetic denervation in patients with nonischemic cardiomyopathy and refractory ventricular arrhythmias: a single-center experience

INTRODUCTION

Cardiac sympathetic denervation (CSD) is an effective therapy for selected patients with drug refractory ventricular arrhythmias (VA). Data about the role of CSD in patients with structural heart disease and VAs are sparse. We herein present our experience of CSD in patients with nonischemic cardiomyopathy and VAs despite prior ablation procedure and/or antiarrhythmic drug (AAD) therapy.

METHODS

A total of ten patients (mean age 61.6 ± 19.6, mean LVEF 29.5 ± 12.1%) with nonischemic dilated cardiomyopathy (NICM) (n = 9) and hypertrophic cardiomyopathy (HCM) (n = 1) underwent CSD (left sided in six and bilateral in four patients) due to refractory VA despite multiple AADs (mean number of AADs was 1.6 ± 0.7) and prior VT ablation (mean number of procedures per patient was 1.5 ± 1.3).

RESULTS

Mean follow-up was 10.1 ± 6.9 months. The median number of VA and ICD shocks decreased significantly from 9.0 and 2.5 episodes 6 months prior to CSD to 0 and 0 episodes within 6 months after CSD (p = 0.012 and p = 0.011). Five patients remained free from sustained VA recurrences. Two patients experienced single ICD shock due to a polymorphic VT (triggered by severe hypokalemia in one patient) and one patient a single shock due to monomorphic VT. One patient had five episodes of slow VT under amiodarone therapy (three of them terminated by antitachycardia pacing) and underwent endo- epicardial re-ablation. Two patients died 1 month after CSD. One of them due to electrical storm and cardiogenic shock and the second one due to refractory cardiogenic shock, without recurrence of VAs though. No major complications of CSD occurred. No patient suffered from Horner syndrome.

CONCLUSION

In this study, CSD was effective for treatment of VAs in patients with structural heart disease refractory to antiarrhythmic drugs and catheter ablation. Further larger studies are required to confirm these findings.

Electrophysiologic effects and outcomes of sympatholysis in patients with recurrent ventricular arrhythmia and structural heart disease

INTRODUCTION

Autonomic modulation has been used as a therapy to control recurrent ventricular arrhythmia (VA). This study was to explore stellate ganglion block (SGB) effect on cardiac electrophysiologic properties and evaluate the long-term outcome of cardiac sympathetic denervation (CSD) for patients with recurrent VA and structural heart disease (SHD).

MATERIALS AND METHODS

Patients who had recurrent VA due to SHD were enrolled prospectively. Electrophysiologic study and ventricular tachycardia (VT) induction were performed before and after left and right SGB. VA burden and long-term outcomes were assessed for a separate patient group who underwent left or bilateral CSD for drug-refractory VA due to SHD.

RESULTS

Electrophysiologic study of nine patients showed that baseline mean (SD) corrected sinus node recovery time (cSNRT) increased from 320.4 (73.3) ms to 402.9 (114.2) ms after left and 482.4 (95.7) ms after bilateral SGB (P = .03). SGB did not significantly change P-R, QRS, and Q-T intervals and ventricular effective refractory period, nor did the inducibility of VA. Nineteen patients underwent left (n = 14) or bilateral (n = 5) CSD. CSD reduced VA burden and appropriate ICD therapies from a median (interquartile range) of 2.5 (0.4-11.6) episodes weekly to 0.1 (0.0-2.4) episodes weekly at 6-month follow-up (P = .002). Three-year freedom from orthotopic heart transplant (OHT) and death was 52.6%. New York Heart Association functional class III/IV and VT rate less than 160 beats per minute were predictors of recurrent VA, OHT, and death.

CONCLUSION

SGB increased cSNRT without changing heart rate. CSD was more beneficial for patients with mild-to-moderate heart failure and faster VA.

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.