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Ajijola OA, Hoover DB, Simerly TM, Brown TC, Yanagawa J, Biniwale RM, Lee JM, Sadeghi A, Khanlou N, Ardell JL, Shivkumar K. Inflammation, oxidative stress, and glial cell activation characterize stellate ganglia from humans with electrical storm. JCI Insight 2017; 2:94715. [PMID: 28931760 DOI: 10.1172/jci.insight.94715] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/08/2017] [Indexed: 01/08/2023] Open
Abstract
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.
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Affiliation(s)
- Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center and.,UCLA Neurocardiology Research Center of Excellence, University of California, Los Angeles, California, USA
| | - Donald B Hoover
- Department of Biomedical Sciences.,Center for Inflammation, Infectious Disease, and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA. Departments of
| | - Thomas M Simerly
- Department of Biomedical Sciences.,Center for Inflammation, Infectious Disease, and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA. Departments of
| | - T Christopher Brown
- Department of Biomedical Sciences.,Center for Inflammation, Infectious Disease, and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA. Departments of
| | | | | | | | | | - Negar Khanlou
- Pathology, University of California, Los Angeles, California, USA
| | - Jeffrey L Ardell
- UCLA Cardiac Arrhythmia Center and.,UCLA Neurocardiology Research Center of Excellence, University of California, Los Angeles, California, USA
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center and.,UCLA Neurocardiology Research Center of Excellence, University of California, Los Angeles, California, USA
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102
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Carlson GM, Libbus I, Amurthur B, KenKnight BH, Verrier RL. Novel method to assess intrinsic heart rate recovery in ambulatory ECG recordings tracks cardioprotective effects of chronic autonomic regulation therapy in patients enrolled in the ANTHEM-HF study. Ann Noninvasive Electrocardiol 2017; 22:e12436. [PMID: 28213914 PMCID: PMC6931843 DOI: 10.1111/anec.12436] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/13/2017] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Postexercise heart rate recovery (HRR) is a powerful and independent predictor of mortality. Autonomic regulation therapy (ART) with chronic vagus nerve stimulation (VNS) has been shown to improve ventricular function in patients with chronic heart failure. However, the effect of ART on HRR in patients with heart failure remains unknown. METHODS A new measure involving quantification of intrinsic HRR was developed for 24-hr ambulatory ECG (AECG) recordings based on spontaneous heart rate changes observed during daily activity in patients with symptomatic heart failure and reduced ejection fraction. Intrinsic HRR values were compared in 21 patients enrolled in the ANTHEM-HF study (NCT01823887) before and after 12 months of chronic ART (10 Hz, 250 μs pulse width, 18% duty cycle, maximum tolerable current amplitude after 10 weeks of titration) and to values from normal subjects (PhysioNet database, n = 54). RESULTS With chronic ART, average intrinsic HRR was improved as indicated by a shortening of the rate-recovery time constant by 8.9% (from 12.3 ± 0.1 at baseline to 11.2 ± 0.1 s, p < .0001) among patients receiving high-intensity stimuli (≥2 mA). In addition, mean heart rate decreased by 8.5 bpm (from 75.9 ± 2.6 to 67.4 ± 2.9 bpm, p = .005) and left ventricular ejection fraction (LVEF) increased by 4.7% (from 32.6 ± 2.0% to 37.3 ± 1.9%, p < .005). CONCLUSION Using a new technique adapted for 24-hr AECG recordings, intrinsic HRR was found to be impaired in patients with symptomatic HF compared to normal subjects. Chronic ART significantly improved intrinsic HRR, indicating an improvement in autonomic function.
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103
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Salavatian S, Beaumont E, Gibbons D, Hammer M, Hoover DB, Armour JA, Ardell JL. Thoracic spinal cord and cervical vagosympathetic neuromodulation obtund nodose sensory transduction of myocardial ischemia. Auton Neurosci 2017; 208:57-65. [PMID: 28919363 DOI: 10.1016/j.autneu.2017.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/07/2017] [Accepted: 08/16/2017] [Indexed: 12/01/2022]
Abstract
BACKGROUND Autonomic regulation therapy involving either vagus nerve stimulation (VNS) or spinal cord stimulation (SCS) represents emerging bioelectronic therapies for heart disease. The objective of this study was to determine if VNS and/or SCS modulate primary cardiac afferent sensory transduction of the ischemic myocardium. METHODS Using extracellular recordings in 19 anesthetized canines, of 88 neurons evaluated, 36 ventricular-related nodose ganglia sensory neurons were identified by their functional activity responses to epicardial touch, chemical activation of their sensory neurites (epicardial veratridine) and great vessel (descending aorta or inferior vena cava) occlusion. Neural responses to 1min left anterior descending (LAD) coronary artery occlusion (CAO) were then evaluated. These interventions were then studied following either: i) SCS [T1-T3 spinal level; 50Hz, 90% motor threshold] or ii) cervical VNS [15-20Hz; 1.2× threshold]. RESULTS LAD occlusion activated 66% of identified nodose ventricular sensory neurons (0.33±0.08-0.79±0.20Hz; baseline to CAO; p<0.002). Basal activity of cardiac-related nodose neurons was differentially reduced by VNS (0.31±0.11 to 0.05±0.02Hz; p<0.05) as compared to SCS (0.36±0.12 to 0.28±0.14, p=0.59), with their activity response to transient LAD CAO being suppressed by either SCS (0.85±0.39-0.11±0.04Hz; p<0.03) or VNS (0.75±0.27-0.12±0.05Hz; p<0.04). VNS did not alter evoked neural responses of cardiac-related nodose neurons to great vessel occlusion. CONCLUSIONS Both VNS and SCS obtund ventricular ischemia induced enhancement of nodose afferent neuronal inputs to the medulla.
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Affiliation(s)
- Siamak Salavatian
- UCLA Neurocardiology Research Program of Excellence, Los Angeles, CA, United States; UCLA Cardiac Arrhythmia Center, Los Angeles, CA, United States
| | - Eric Beaumont
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, TN, United States; Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, United States
| | - David Gibbons
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, TN, United States
| | - Matthew Hammer
- UCLA Neurocardiology Research Program of Excellence, Los Angeles, CA, United States
| | - Donald B Hoover
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, TN, United States; Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, United States
| | - J Andrew Armour
- UCLA Neurocardiology Research Program of Excellence, Los Angeles, CA, United States; UCLA Cardiac Arrhythmia Center, Los Angeles, CA, United States
| | - Jeffrey L Ardell
- UCLA Neurocardiology Research Program of Excellence, Los Angeles, CA, United States; UCLA Cardiac Arrhythmia Center, Los Angeles, CA, United States.
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104
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Kember G, Ardell JL, Shivkumar K, Armour JA. Recurrent myocardial infarction: Mechanisms of free-floating adaptation and autonomic derangement in networked cardiac neural control. PLoS One 2017; 12:e0180194. [PMID: 28692680 PMCID: PMC5503241 DOI: 10.1371/journal.pone.0180194] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 06/12/2017] [Indexed: 12/20/2022] Open
Abstract
The cardiac nervous system continuously controls cardiac function whether or not pathology is present. While myocardial infarction typically has a major and catastrophic impact, population studies have shown that longer-term risk for recurrent myocardial infarction and the related potential for sudden cardiac death depends mainly upon standard atherosclerotic variables and autonomic nervous system maladaptations. Investigative neurocardiology has demonstrated that autonomic control of cardiac function includes local circuit neurons for networked control within the peripheral nervous system. The structural and adaptive characteristics of such networked interactions define the dynamics and a new normal for cardiac control that results in the aftermath of recurrent myocardial infarction and/or unstable angina that may or may not precipitate autonomic derangement. These features are explored here via a mathematical model of cardiac regulation. A main observation is that the control environment during pathology is an extrapolation to a setting outside prior experience. Although global bounds guarantee stability, the resulting closed-loop dynamics exhibited while the network adapts during pathology are aptly described as 'free-floating' in order to emphasize their dependence upon details of the network structure. The totality of the results provide a mechanistic reasoning that validates the clinical practice of reducing sympathetic efferent neuronal tone while aggressively targeting autonomic derangement in the treatment of ischemic heart disease.
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Affiliation(s)
- Guy Kember
- Dept. of Engineering Mathematics and Internetworking/Faculty of Engineering/Dalhousie University, Halifax, NS, Canada
- * E-mail:
| | - Jeffrey L. Ardell
- David Geffen School of Medicine/Cardiac Arrhythmia Center, University of California – Los Angeles (UCLA), Los Angeles, CA, United States of America
| | - Kalyanam Shivkumar
- David Geffen School of Medicine/Cardiac Arrhythmia Center, University of California – Los Angeles (UCLA), Los Angeles, CA, United States of America
| | - J. Andrew Armour
- David Geffen School of Medicine/Cardiac Arrhythmia Center, University of California – Los Angeles (UCLA), Los Angeles, CA, United States of America
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105
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Neurocardiology: Cardiovascular Changes and Specific Brain Region Infarcts. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5646348. [PMID: 28758117 PMCID: PMC5512017 DOI: 10.1155/2017/5646348] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 05/15/2017] [Indexed: 11/18/2022]
Abstract
There are complex and dynamic reflex control networks between the heart and the brain, including cardiac and intrathoracic ganglia, spinal cord, brainstem, and central nucleus. Recent literature based on animal model and clinical trials indicates a close link between cardiac function and nervous systems. It is noteworthy that the autonomic nervous-based therapeutics has shown great potential in the management of atrial fibrillation, ventricular arrhythmia, and myocardial remodeling. However, the potential mechanisms of postoperative brain injury and cardiovascular changes, particularly heart rate variability and the presence of arrhythmias, are not understood. In this chapter, we will describe mechanisms of brain damage undergoing cardiac surgery and focus on the interaction between cardiovascular changes and damage to specific brain regions.
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106
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Kingma JG, Simard D, Rouleau JR. Influence of cardiac nerve status on cardiovascular regulation and cardioprotection. World J Cardiol 2017; 9:508-520. [PMID: 28706586 PMCID: PMC5491468 DOI: 10.4330/wjc.v9.i6.508] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 03/22/2017] [Accepted: 04/24/2017] [Indexed: 02/07/2023] Open
Abstract
Neural elements of the intrinsic cardiac nervous system transduce sensory inputs from the heart, blood vessels and other organs to ensure adequate cardiac function on a beat-to-beat basis. This inter-organ crosstalk is critical for normal function of the heart and other organs; derangements within the nervous system hierarchy contribute to pathogenesis of organ dysfunction. The role of intact cardiac nerves in development of, as well as protection against, ischemic injury is of current interest since it may involve recruitment of intrinsic cardiac ganglia. For instance, ischemic conditioning, a novel protection strategy against organ injury, and in particular remote conditioning, is likely mediated by activation of neural pathways or by endogenous cytoprotective blood-borne substances that stimulate different signalling pathways. This discovery reinforces the concept that inter-organ communication, and maintenance thereof, is key. As such, greater understanding of mechanisms and elucidation of treatment strategies is imperative to improve clinical outcomes particularly in patients with comorbidities. For instance, autonomic imbalance between sympathetic and parasympathetic nervous system regulation can initiate cardiovascular autonomic neuropathy that compromises cardiac stability and function. Neuromodulation therapies that directly target the intrinsic cardiac nervous system or other elements of the nervous system hierarchy are currently being investigated for treatment of different maladies in animal and human studies.
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107
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Chui RW, Buckley U, Rajendran PS, Vrabec T, Shivkumar K, Ardell JL. Bioelectronic block of paravertebral sympathetic nerves mitigates post-myocardial infarction ventricular arrhythmias. Heart Rhythm 2017. [PMID: 28629852 DOI: 10.1016/j.hrthm.2017.06.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Autonomic dysfunction contributes to induction of ventricular tachyarrhythmia (VT). OBJECTIVE To determine the efficacy of charge-balanced direct current (CBDC), applied to the T1-T2 segment of the paravertebral sympathetic chain, on VT inducibility post-myocardial infarction (MI). METHODS In a porcine model, CBDC was applied in acute animals (n = 7) to optimize stimulation parameters for sympathetic blockade and in chronic MI animals (n = 7) to evaluate the potential for VTs. Chronic MI was induced by microsphere embolization of the left anterior descending coronary artery. At termination, in anesthetized animals and following thoracotomy, an epicardial sock array was placed over both ventricles and a quadripolar carousel electrode positioned underlying the right T1-T2 paravertebral chain. In acute animals, the efficacy of CBDC carousel (CBDCC) block was assessed by evaluating cardiac function during T2 paravertebral ganglion stimulation with and without CBDCC. In chronic MI animals, VT inducibility was assessed by extrasystolic (S1-S2) stimulations at baseline and under >66% CBDCC blockade of T2-evoked sympathoexcitation. RESULTS CBDCC demonstrated a current-dependent and reversible block without impacting basal cardiac function. VT was induced at baseline in all chronic MI animals. One animal died after baseline induction. Of the 6 remaining animals, only 1 was reinducible with simultaneous CBDCC application (P < .002 from baseline). The ventricular effective refractory period (VERP) was prolonged with CBDCC (323 ± 26 ms) compared to baseline (271 ± 32 ms) (P < .05). CONCLUSIONS Axonal block of the T1-T2 paravertebral chain with CBDCC reduced VT in a chronic MI model. CBDCC prolonged VERP, without altering baseline cardiac function, resulting in improved electrical stability.
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Affiliation(s)
- Ray W Chui
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California; Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Una Buckley
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California
| | - Pradeep S Rajendran
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California; Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Tina Vrabec
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Kalyanam Shivkumar
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California; Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Jeffrey L Ardell
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, Los Angeles, California; Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, California.
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108
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Ardell JL, Shivkumar K. Sympathetic neural recording-It is all in the details. Heart Rhythm 2017; 14:972-973. [PMID: 28438720 DOI: 10.1016/j.hrthm.2017.04.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Indexed: 10/19/2022]
Affiliation(s)
- Jeffrey L Ardell
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA.
| | - Kalyanam Shivkumar
- University of California-Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA
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109
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Liu B. Integrative Views of the Heart in Chinese and Western Medicine. INTEGRATIVE MEDICINE INTERNATIONAL 2017; 4:46-51. [DOI: 10.1159/000466695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
There is a general acknowledgement in almost all civilizations that the heart is the most important organ in the human body. Both Chinese medicine and Western traditional medicine have a long history of heart research, but they have developed different points of view based on the basic cognition. Traditional Chinese medicine is good at summarizing the correspondence and relationship between the heart and exterior things. The physiological functions of the heart are governing blood and vessels, controlling the mind, opening into the tongue, manifesting on the face, and so on, while modern Western medicine does well in exploring the anatomical structure, spacial connection, and micromechanical character of the organ. Chinese medicine and Western medicine have established the diagnosis and management system, respectively, from their own angles. Combining the knowledge of Chinese and Western medicine can take the advantages of either of the two, making it deeper and more comprehensive for studying and treating heart diseases.
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110
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The role of the autonomic nervous system in arrhythmias and sudden cardiac death. Auton Neurosci 2017; 205:1-11. [PMID: 28392310 DOI: 10.1016/j.autneu.2017.03.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 03/11/2017] [Accepted: 03/28/2017] [Indexed: 12/16/2022]
Abstract
The autonomic nervous system (ANS) is complex and plays an important role in cardiac arrhythmia pathogenesis. A deeper understanding of the anatomy and development of the ANS has shed light on its involvement in cardiac arrhythmias. Alterations in levels of Sema-3a and NGF, both growth factors involved in innervation patterning during development of the ANS, leads to cardiac arrhythmias. Dysregulation of the ANS, including polymorphisms in genes involved in ANS development, have been implicated in sudden infant death syndrome. Disruptions in the sympathetic and/or parasympathetic systems of the ANS can lead to cardiac arrhythmias and can vary depending on the type of arrhythmia. Simultaneous stimulation of both the sympathetic and parasympathetic systems is thought to lead to atrial fibrillation whereas increased sympathetic stimulation is thought to lead to ventricular fibrillation or ventricular tachycardia. In inherited arrhythmia syndromes, such as Long QT and Catecholaminergic Polymorphic Ventricular Tachycardia, sympathetic system stimulation is thought to lead to ventricular tachycardia, subsequent arrhythmias, and in severe cases, cardiac death. On the other hand, arrhythmic events in Brugada Syndrome have been associated with periods of high parasympathetic tone. Increasing evidence suggests that modulation of the ANS as a therapeutic strategy in the treatment of cardiac arrhythmias is safe and effective. Further studies investigating the involvement of the ANS in arrhythmia pathogenesis and its modulation for the treatment of cardiac arrhythmias is warranted.
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111
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Buckley U, Chui RW, Rajendran PS, Vrabec T, Shivkumar K, Ardell JL. Bioelectronic neuromodulation of the paravertebral cardiac efferent sympathetic outflow and its effect on ventricular electrical indices. Heart Rhythm 2017; 14:1063-1070. [PMID: 28219848 DOI: 10.1016/j.hrthm.2017.02.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Neuromodulation of the paravertebral ganglia by using symmetric voltage controlled kilohertz frequency alternating current (KHFAC) has the potential to be a reversible alternative to surgical intervention in patients with refractory ventricular arrhythmias. KHFAC creates scalable focal inhibition of action potential conduction. OBJECTIVE The purpose of this article was to evaluate the efficacy of KHFAC when applied to the T1-T2 paravertebral chain to mitigate sympathetic outflow to the heart. METHODS In anesthetized, vagotomized, porcine subjects, the heart was exposed via a midline sternotomy along with paravertebral chain ganglia. The T3 paravertebral ganglion was electrically stimulated, and activation recovery intervals (ARIs) were obtained from a 56-electrode sock placed over both ventricles. A bipolar Ag electrode was wrapped around the paravertebral chain between T1 and T2 and connected to a symmetric voltage controlled KHFAC generator. A comparison of cardiac indices during T3 stimulation conditions, with and without KHFAC, provided a measure of block efficacy. RESULTS Right-sided T3 stimulation (at 4 Hz) was titrated to produce reproducible ARI changes from baseline (52 ± 30 ms). KHFAC resulted in a 67% mitigation of T3 electrical stimulation effects on ARI (18.5 ± 22 ms; P < .005). T3 stimulation repeated after KHFAC produced equivalent ARI changes as control. KHFAC evoked a transient functional sympathoexcitation at onset that was inversely related to frequency and directly related to intensity. The optimum block threshold was 15 kHz and 15 V. CONCLUSION KHFAC applied to nexus (convergence) points of the cardiac nervous system produces a graded and reversible block of underlying axons. As such, KHFAC has the therapeutic potential for on-demand and reversible mitigation of sympathoexcitation.
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Affiliation(s)
- Una Buckley
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California
| | - Ray W Chui
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California; Molecular, Cellular, & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Pradeep S Rajendran
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California; Molecular, Cellular, & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Tina Vrabec
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Kalyanam Shivkumar
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California; Molecular, Cellular, & Integrative Physiology Program, UCLA, Los Angeles, California
| | - Jeffrey L Ardell
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California; Molecular, Cellular, & Integrative Physiology Program, UCLA, Los Angeles, California.
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112
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Meyer C, Scherschel K. Ventricular tachycardia in ischemic heart disease: the sympathetic heart and its scars. Am J Physiol Heart Circ Physiol 2017; 312:H549-H551. [PMID: 28188212 DOI: 10.1152/ajpheart.00061.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 01/04/2023]
Affiliation(s)
- Christian Meyer
- Department of Cardiology-Electrophysiology, Cardiac Neurophysiology and Electrophysiology Research Group, University Heart Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany; and German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Katharina Scherschel
- Department of Cardiology-Electrophysiology, Cardiac Neurophysiology and Electrophysiology Research Group, University Heart Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany; and German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
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113
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Ajijola OA, Lux RL, Khahera A, Kwon O, Aliotta E, Ennis DB, Fishbein MC, Ardell JL, Shivkumar K. Sympathetic modulation of electrical activation in normal and infarcted myocardium: implications for arrhythmogenesis. Am J Physiol Heart Circ Physiol 2017; 312:H608-H621. [PMID: 28087519 DOI: 10.1152/ajpheart.00575.2016] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 01/03/2017] [Accepted: 01/04/2017] [Indexed: 11/22/2022]
Abstract
The influence of cardiac sympathetic innervation on electrical activation in normal and chronically infarcted ventricular myocardium is not understood. Yorkshire pigs with normal hearts (NL, n = 12) or anterior myocardial infarction (MI, n = 9) underwent high-resolution mapping of the anteroapical left ventricle at baseline and during left and right stellate ganglion stimulation (LSGS and RSGS, respectively). Conduction velocity (CV), activation times (ATs), and directionality of propagation were measured. Myocardial fiber orientation was determined using diffusion tensor imaging and histology. Longitudinal CV (CVL) was increased by RSGS (0.98 ± 0.11 vs. 1.2 ± 0.14m/s, P < 0.001) but not transverse CV (CVT). This increase was abrogated by β-adrenergic receptor and gap junction (GJ) blockade. Neither CVL nor CVT was increased by LSGS. In the peri-infarct region, both RSGS and LSGS shortened ARIs in sinus rhythm (423 ± 37 vs. 322 ± 30 ms, P < 0.001, and 423 ± 36 vs. 398 ± 36 ms, P = 0.035, respectively) and altered activation patterns in all animals. CV, as estimated by mean ATs, increased in a directionally dependent manner by RSGS (14.6 ± 1.2 vs. 17.3 ± 1.6 ms, P = 0.015), associated with GJ lateralization. RSGS and LSGS inhomogeneously modulated AT and induced relative or absolute functional activation delay in parts of the mapped regions in 75 and 67%, respectively, in MI animals, and in 0 and 15%, respectively, in control animals (P < 0.001 for both). In conclusion, sympathoexcitation increases CV in normal myocardium and modulates activation propagation in peri-infarcted ventricular myocardium. These data demonstrate functional control of arrhythmogenic peri-infarct substrates by sympathetic nerves and in part explain the temporal nature of arrhythmogenesis.NEW & NOTEWORTHY This study demonstrates regional control of conduction velocity in normal hearts by sympathetic nerves. In infarcted hearts, however, not only is modulation of propagation heterogeneous, some regions showed paradoxical conduction slowing. Sympathoexcitation altered propagation in all infarcted hearts studied, and we describe the temporal arrhythmogenic potential of these findings.Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/sympathetic-nerves-and-cardiac-propagation/.
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Affiliation(s)
- Olujimi A Ajijola
- Cardiac Arrhythmia Center, University of California, Los Angeles, California; .,Neurocardiology Research Center of Excellence, University of California, Los Angeles, California
| | - Robert L Lux
- Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Anadjeet Khahera
- Cardiac Arrhythmia Center, University of California, Los Angeles, California
| | - OhJin Kwon
- Cardiac Arrhythmia Center, University of California, Los Angeles, California
| | - Eric Aliotta
- Department of Radiology, University of California, Los Angeles, California
| | - Daniel B Ennis
- Department of Radiology, University of California, Los Angeles, California
| | - Michael C Fishbein
- Department of Pathology, University of California, Los Angeles, California; and
| | - Jeffrey L Ardell
- Cardiac Arrhythmia Center, University of California, Los Angeles, California.,Neurocardiology Research Center of Excellence, University of California, Los Angeles, California
| | - Kalyanam Shivkumar
- Cardiac Arrhythmia Center, University of California, Los Angeles, California.,Neurocardiology Research Center of Excellence, University of California, Los Angeles, California
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114
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Coskun V, Lombardo DM. Studying the pathophysiologic connection between cardiovascular and nervous systems using stem cells. J Neurosci Res 2016; 94:1499-1510. [PMID: 27629698 DOI: 10.1002/jnr.23924] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/25/2016] [Accepted: 08/25/2016] [Indexed: 12/17/2022]
Abstract
The cardiovascular and nervous systems are deeply connected during development, health, and disease. Both systems affect and regulate the development of each other during embryogenesis and the early postnatal period. Specialized neural crest cells contribute to cardiac structures, and a number of growth factors released from the cardiac tissue (e.g., glial cell line-derived neurotrophic factor, neurturin, nerve growth factor, Neurotrophin-3) ensure proper maturation of the incoming parasympathetic and sympathetic neurons. Physiologically, the cardiovascular and nervous systems operate in harmony to adapt to various physical and emotional conditions to maintain homeostasis through sympathetic and parasympathetic nervous systems. Moreover, neurocardiac regulation involves a neuroaxis consisting of cortex, amygdala, and other subcortical structures, which have the ability to modify lower-level neurons in the hierarchy. Given the interconnectivity of cardiac and neural systems, when one undergoes pathological changes, the other is affected to a certain extent. In addition, there are specific neurocardiac diseases that affect both systems simultaneously, such as Huntington disease, Lewy body diseases, Friedreich ataxia, congenital heart diseases, Danon disease, and Timothy syndrome. Over the last decade, in vitro modeling of neurocardiac diseases using induced pluripotent stem cells (iPSCs) has provided an invaluable opportunity to elevate our knowledge about the brain-heart connection, since previously primary cardiomyocytes and neurons had been extremely difficult to maintain long-term in vitro. Ultimately, the ability of iPSC technology to model abnormal functional phenotypes of human neurocardiac disorders, combined with the ease of therapeutic screening using this approach, will transform patient care through personalized medicine in the future. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Volkan Coskun
- Department of Medicine, Division of Cardiology, University of California, Irvine, Irvine, California.
| | - Dawn M Lombardo
- Department of Medicine, Division of Cardiology, University of California, Irvine, Irvine, California
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115
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Salavatian S, Beaumont E, Longpré JP, Armour JA, Vinet A, Jacquemet V, Shivkumar K, Ardell JL. Vagal stimulation targets select populations of intrinsic cardiac neurons to control neurally induced atrial fibrillation. Am J Physiol Heart Circ Physiol 2016; 311:H1311-H1320. [PMID: 27591222 DOI: 10.1152/ajpheart.00443.2016] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/30/2016] [Indexed: 12/30/2022]
Abstract
Mediastinal nerve stimulation (MNS) reproducibly evokes atrial fibrillation (AF) by excessive and heterogeneous activation of intrinsic cardiac (IC) neurons. This study evaluated whether preemptive vagus nerve stimulation (VNS) impacts MNS-induced evoked changes in IC neural network activity to thereby alter susceptibility to AF. IC neuronal activity in the right atrial ganglionated plexus was directly recorded in anesthetized canines (n = 8) using a linear microelectrode array concomitant with right atrial electrical activity in response to: 1) epicardial touch or great vessel occlusion vs. 2) stellate or vagal stimulation. From these stressors, post hoc analysis (based on the Skellam distribution) defined IC neurons so recorded as afferent, efferent, or convergent (afferent and efferent inputs) local circuit neurons (LCN). The capacity of right-sided MNS to modify IC activity in the induction of AF was determined before and after preemptive right (RCV)- vs. left (LCV)-sided VNS (15 Hz, 500 μs; 1.2× bradycardia threshold). Neuronal (n = 89) activity at baseline (0.11 ± 0.29 Hz) increased during MNS-induced AF (0.51 ± 1.30 Hz; P < 0.001). Convergent LCNs were preferentially activated by MNS. Preemptive RCV reduced MNS-induced changes in LCN activity (by 70%) while mitigating MNS-induced AF (by 75%). Preemptive LCV reduced LCN activity by 60% while mitigating AF potential by 40%. IC neuronal synchrony increased during neurally induced AF, a local neural network response mitigated by preemptive VNS. These antiarrhythmic effects persisted post-VNS for, on average, 26 min. In conclusion, VNS preferentially targets convergent LCNs and their interactive coherence to mitigate the potential for neurally induced AF. The antiarrhythmic properties imposed by VNS exhibit memory.
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Affiliation(s)
- Siamak Salavatian
- Faculty of Medicine, Department of Physiology, Université de Montréal, Quebec, Canada.,Centre de Recherche, Hôpital du Sacré-Coeur, Montréal, Quebec, Canada.,Neurocardiology Research Center of Excellence, University of California Los Angeles, Los Angeles, California; and
| | - Eric Beaumont
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Jean-Philippe Longpré
- Faculty of Medicine, Department of Physiology, Université de Montréal, Quebec, Canada.,Centre de Recherche, Hôpital du Sacré-Coeur, Montréal, Quebec, Canada
| | - J Andrew Armour
- Neurocardiology Research Center of Excellence, University of California Los Angeles, Los Angeles, California; and.,Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, California
| | - Alain Vinet
- Faculty of Medicine, Department of Physiology, Université de Montréal, Quebec, Canada.,Centre de Recherche, Hôpital du Sacré-Coeur, Montréal, Quebec, Canada
| | - Vincent Jacquemet
- Faculty of Medicine, Department of Physiology, Université de Montréal, Quebec, Canada.,Centre de Recherche, Hôpital du Sacré-Coeur, Montréal, Quebec, Canada
| | - Kalyanam Shivkumar
- Neurocardiology Research Center of Excellence, University of California Los Angeles, Los Angeles, California; and.,Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, California
| | - Jeffrey L Ardell
- Neurocardiology Research Center of Excellence, University of California Los Angeles, Los Angeles, California; and .,Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, California
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116
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Kalla M, Herring N, Paterson DJ. Cardiac sympatho-vagal balance and ventricular arrhythmia. Auton Neurosci 2016; 199:29-37. [PMID: 27590099 PMCID: PMC5334443 DOI: 10.1016/j.autneu.2016.08.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 12/11/2022]
Abstract
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. We review advances in mechanistic research in the cardiac autonomic nervous system. This is discussed in relation to neuromodulatory therapy for ventricular arrhythmia. Neuromodulation therapies can influence both neurotransmitters and co-transmitters. This may therefore improve on conventional medical treatment.
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Affiliation(s)
| | - Neil Herring
- Corresponding author at: Burdon Sanderson Cardiac Science Centre, Dept. of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, OX13PT, UK.Burdon Sanderson Cardiac Science CentreDept. of Physiology, Anatomy and GeneticsUniversity of OxfordParks RoadOX13PTUK
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