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Hanna P, Ardell JL. Cardiac Neuroanatomy and Fundamentals of Neurocardiology. Card Electrophysiol Clin 2024; 16:229-237. [PMID: 39084716 DOI: 10.1016/j.ccep.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Cardiac control is mediated via nested-feedback reflex control networks involving the intrinsic cardiac ganglia, intra-thoracic extra-cardiac ganglia, spinal cord, brainstem, and higher centers. This control system is optimized to respond to normal physiologic stressors; however, it can be catastrophically disrupted by pathologic events such as myocardial ischemia. In fact, it is now recognized that cardiac disease progression reflects the dynamic interplay between adverse remodeling of the cardiac substrate coupled with autonomic dysregulation. With advances in understanding of this network dynamic in normal and pathologic states, neuroscience-based neuromodulation therapies can be devised for the management of acute and chronic cardiac pathologies.
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Affiliation(s)
- Peter Hanna
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; UCLA Neurocardiology Research Program of Excellence, UCLA, Los Angeles, CA 90095, USA
| | - Jeffrey L Ardell
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; UCLA Neurocardiology Research Program of Excellence, UCLA, Los Angeles, CA 90095, USA.
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2
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Kuwabara Y, Wong B, Mahajan A, Salavatian S. Pharmacologic, Surgical, and Device-Based Cardiac Neuromodulation. Card Electrophysiol Clin 2024; 16:315-324. [PMID: 39084724 DOI: 10.1016/j.ccep.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
The cardiac autonomic nervous system plays a key role in maintaining normal cardiac physiology, and once disrupted, it worsens the cardiac disease states. Neuromodulation therapies have been emerging as new treatment options, and various techniques have been introduced to mitigate autonomic nervous imbalances to help cardiac patients with their disease conditions and symptoms. In this review article, we discuss various neuromodulation techniques used in clinical settings to treat cardiac diseases.
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Affiliation(s)
- Yuki Kuwabara
- Department of Anesthesiology and Perioperative Medicine of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA
| | - Benjamin Wong
- Department of Anesthesiology and Perioperative Medicine of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA
| | - Aman Mahajan
- Department of Anesthesiology and Perioperative Medicine of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA
| | - Siamak Salavatian
- Department of Anesthesiology and Perioperative Medicine of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA; Department of Medicine, Division of Cardiology, University of Pittsburgh, Pittsburgh, PA, USA.
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Thompson N, Ravagli E, Mastitskaya S, Challita R, Hadaya J, Iacoviello F, Idil AS, Shearing PR, Ajijola OA, Ardell JL, Shivkumar K, Holder D, Aristovich K. Towards spatially selective efferent neuromodulation: anatomical and functional organization of cardiac fibres in the porcine cervical vagus nerve. J Physiol 2024. [PMID: 39183636 DOI: 10.1113/jp286494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 08/09/2024] [Indexed: 08/27/2024] Open
Abstract
Spatially selective vagus nerve stimulation (sVNS) offers a promising approach for addressing heart disease with enhanced precision. Despite its therapeutic potential, VNS is limited by off-target effects and the need for time-consuming titration. Our research aimed to determine the spatial organization of cardiac afferent and efferent fibres within the vagus nerve of pigs to achieve targeted neuromodulation. Using trial-and-error sVNS in vivo and ex vivo micro-computed tomography fascicle tracing, we found significant spatial separation between cardiac afferent and cardiac efferent fibres at the mid-cervical level and they were localized on average on opposite sides of the nerve cross-section. This was consistent between both in vivo and ex vivo methods. Specifically, cardiac afferent fibres were located near pulmonary fibres, consistent with findings of cardiopulmonary convergent circuits and, notably, cardiac efferent fascicles were exclusive. These cardiac efferent regions were located in close proximity to the recurrent laryngeal regions. This is consistent with the roughly equitable spread across the nerve of the afferent and efferent fibres. Our study demonstrated that targeted neuromodulation via sVNS could achieve scalable heart rate decreases without eliciting cardiac afferent-related reflexes; this is desirable for reducing sympathetic overactivation associated with heart disease. These findings indicate that understanding the spatial organization of cardiac-related fibres within the vagus nerve can lead to more precise and effective VNS therapy, minimizing off-target effects and potentially mitigating the need for titration. KEY POINTS: Spatially selective vagus nerve stimulation (sVNS) presents a promising approach for addressing chronic heart disease with enhanced precision. Our study reveals significant spatial separation between cardiac afferent and efferent fibres in the vagus nerve, particularly at the mid-cervical level. Utilizing trial-and-error sVNS in vivo and micro-computed tomography fascicle tracing, we demonstrate the potential for targeted neuromodulation, achieving therapeutic effects such as scalable heart rate decrease without stimulating cardiac afferent-related reflexes. This spatial understanding opens avenues for more effective VNS therapy, minimizing off-target effects and potentially eliminating the need for titration, thereby expediting therapeutic outcomes in myocardial infarction and related conditions.
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Affiliation(s)
- Nicole Thompson
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Enrico Ravagli
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Svetlana Mastitskaya
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Ronald Challita
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Joseph Hadaya
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Francesco Iacoviello
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, UK
| | - Ahmad Shah Idil
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Paul R Shearing
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, UK
| | - Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jeffrey L Ardell
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - David Holder
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Kirill Aristovich
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
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4
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Zafeiropoulos S, Ahmed U, Bikou A, Mughrabi IT, Stavrakis S, Zanos S. Vagus nerve stimulation for cardiovascular diseases: Is there light at the end of the tunnel? Trends Cardiovasc Med 2024; 34:327-337. [PMID: 37506989 DOI: 10.1016/j.tcm.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/12/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023]
Abstract
Autonomic dysfunction and chronic inflammation contribute to the pathogenesis and progression of several cardiovascular diseases (CVD), such as heart failure with preserved ejection fraction, atherosclerotic CVD, pulmonary arterial hypertension, and atrial fibrillation. The vagus nerve provides parasympathetic innervation to the heart, vessels, and lungs, and is also implicated in the neural control of inflammation through a neuroimmune pathway involving the spleen. Stimulation of the vagus nerve (VNS) can in principle restore autonomic balance and suppress inflammation, with potential therapeutic benefits in these diseases. Although VNS ameliorated CVD in several animal models, early human studies have demonstrated variable efficacy. The purpose of this review is to discuss the rationale behind the use of VNS in the treatment of CVD, to critically review animal and human studies of VNS in CVD, and to propose possible means to overcome the challenges in the clinical translation of VNS in CVD.
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Affiliation(s)
- Stefanos Zafeiropoulos
- Elmezzi Graduate School of Molecular Medicine at Northwell Health, Manhasset, NY, USA; Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Umair Ahmed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Alexia Bikou
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Ibrahim T Mughrabi
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Stavros Stavrakis
- Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Stavros Zanos
- Elmezzi Graduate School of Molecular Medicine at Northwell Health, Manhasset, NY, USA; Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA.
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5
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Reardon C. Comment on "No consistent evidence for the anti-inflammatory effect of vagus nerve stimulation in humans: A systematic review and meta-analysis". Brain Behav Immun 2024; 119:1018. [PMID: 38447885 DOI: 10.1016/j.bbi.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 01/18/2024] [Accepted: 03/03/2024] [Indexed: 03/08/2024] Open
Affiliation(s)
- Colin Reardon
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, UC Davis, Davis, CA, United States
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Berthon A, Wernisch L, Stoukidi M, Thornton M, Tessier-Lariviere O, Fortier-Poisson P, Mamen J, Pinkney M, Lee S, Sarkans E, Annecchino L, Appleton B, Garsed P, Patterson B, Gonshaw S, Jakopec M, Shunmugam S, Edwards T, Tukiainen A, Jennings J, Lajoie G, Hewage E, Armitage O. Using neural biomarkers to personalize dosing of vagus nerve stimulation. Bioelectron Med 2024; 10:15. [PMID: 38880906 PMCID: PMC11181600 DOI: 10.1186/s42234-024-00147-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/17/2024] [Indexed: 06/18/2024] Open
Abstract
BACKGROUND Vagus nerve stimulation (VNS) is an established therapy for treating a variety of chronic diseases, such as epilepsy, depression, obesity, and for stroke rehabilitation. However, lack of precision and side-effects have hindered its efficacy and extension to new conditions. Achieving a better understanding of the relationship between VNS parameters and neural and physiological responses is therefore necessary to enable the design of personalized dosing procedures and improve precision and efficacy of VNS therapies. METHODS We used biomarkers from recorded evoked fiber activity and short-term physiological responses (throat muscle, cardiac and respiratory activity) to understand the response to a wide range of VNS parameters in anaesthetised pigs. Using signal processing, Gaussian processes (GP) and parametric regression models we analyse the relationship between VNS parameters and neural and physiological responses. RESULTS Firstly, we illustrate how considering multiple stimulation parameters in VNS dosing can improve the efficacy and precision of VNS therapies. Secondly, we describe the relationship between different VNS parameters and the evoked fiber activity and show how spatially selective electrodes can be used to improve fiber recruitment. Thirdly, we provide a detailed exploration of the relationship between the activations of neural fiber types and different physiological effects. Finally, based on these results, we discuss how recordings of evoked fiber activity can help design VNS dosing procedures that optimize short-term physiological effects safely and efficiently. CONCLUSION Understanding of evoked fiber activity during VNS provide powerful biomarkers that could improve the precision, safety and efficacy of VNS therapies.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Guillaume Lajoie
- Université de Montréal and Mila-Quebec AI Institute, Montréal, Canada
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Owens MM, Dalal S, Radovic A, Fernandes L, Syed H, Herndon MK, Cooper C, Singh K, Beaumont E. Vagus nerve stimulation alleviates cardiac dysfunction and inflammatory markers during heart failure in rats. Auton Neurosci 2024; 253:103162. [PMID: 38513382 PMCID: PMC11318104 DOI: 10.1016/j.autneu.2024.103162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/21/2024] [Accepted: 02/28/2024] [Indexed: 03/23/2024]
Abstract
Vagus nerve stimulation (VNS) is under clinical investigation as a therapy for heart failure with reduced ejection fraction (HFrEF). This study aimed to investigate its therapeutic effects on three main components of heart failure: cardiac function, cardiac remodeling and central neuroinflammation using a pressure overload (PO) rat model. Male Sprague-Dawley rats were divided into four groups: PO, PO + VNS, PO + VNS sham, and controls. All rats, except controls, underwent a PO surgery to constrict the thoracic aorta (~50 %) to induce HFrEF. Open loop VNS therapy was continuously administered to PO + VNS rats at 20 Hz, 1.0 mA for 60 days. Evaluation of cardiac function and structure via echocardiograms showed decreases in stroke volume and relative ejection fraction and increases in the internal diameter of the left ventricle during systole and diastole in PO rats (p < 0.05). However, these PO-induced adverse changes were alleviated with VNS therapy. Additionally, PO rats exhibited significant increases in myocyte cross sectional areas indicating hypertrophy, along with significant increases in myocardial fibrosis and apoptosis, all of which were reversed by VNS therapy (p < 0.05). Furthermore, VNS mitigated microglial activation in two central autonomic nuclei: the paraventricular nucleus of the hypothalamus and locus coeruleus. These findings demonstrate that when VNS therapy is initiated at an early stage of HFrEF progression (<10 % reduction in relative ejection fraction), the supplementation of vagal activity is effective in restoring multi organ homeostasis in a PO model.
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Affiliation(s)
- Misty M Owens
- Department of Biomedical Sciences, East Tennessee State University, Stanton-Gerber Hall, 178 Maple Ave., P.O. Box 70582, Mountain Home, TN, 37684, United States of America
| | - Suman Dalal
- Department of Health Sciences, East Tennessee State University, 248 Lamb Hall, PO Box 70673, Johnson City, TN, 37614, United States of America; Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, 1276 Gilbreath Dr., Box 70300, Johnson City, TN 37614, United States of America
| | - Aleksandra Radovic
- Department of Biomedical Sciences, East Tennessee State University, Stanton-Gerber Hall, 178 Maple Ave., P.O. Box 70582, Mountain Home, TN, 37684, United States of America
| | - Luciano Fernandes
- Department of Biomedical Sciences, East Tennessee State University, Stanton-Gerber Hall, 178 Maple Ave., P.O. Box 70582, Mountain Home, TN, 37684, United States of America
| | - Hassan Syed
- Department of Biomedical Sciences, East Tennessee State University, Stanton-Gerber Hall, 178 Maple Ave., P.O. Box 70582, Mountain Home, TN, 37684, United States of America
| | - Mary-Katherine Herndon
- Department of Biomedical Sciences, East Tennessee State University, Stanton-Gerber Hall, 178 Maple Ave., P.O. Box 70582, Mountain Home, TN, 37684, United States of America
| | - Coty Cooper
- Department of Biomedical Sciences, East Tennessee State University, Stanton-Gerber Hall, 178 Maple Ave., P.O. Box 70582, Mountain Home, TN, 37684, United States of America
| | - Krishna Singh
- Department of Biomedical Sciences, East Tennessee State University, Stanton-Gerber Hall, 178 Maple Ave., P.O. Box 70582, Mountain Home, TN, 37684, United States of America; Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, 1276 Gilbreath Dr., Box 70300, Johnson City, TN 37614, United States of America; James H. Quillen Veterans Affairs Medical Center, Lamont St & Veterans Way, Johnson City, TN 37604, United States of America
| | - Eric Beaumont
- Department of Biomedical Sciences, East Tennessee State University, Stanton-Gerber Hall, 178 Maple Ave., P.O. Box 70582, Mountain Home, TN, 37684, United States of America; Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, 1276 Gilbreath Dr., Box 70300, Johnson City, TN 37614, United States of America.
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8
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Saha R, Van Helden D, Hopper MS, Low WC, Netoff TI, Osborn J, Wang JP. Impact of anesthesia on micromagnetic stimulation ( μMS) of the vagus nerve. Biomed Phys Eng Express 2024; 10:035028. [PMID: 38565093 DOI: 10.1088/2057-1976/ad3968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 04/02/2024] [Indexed: 04/04/2024]
Abstract
To treat diseases associated with vagal nerve control of peripheral organs, it is necessary to selectively activate efferent and afferent fibers in the vagus. As a result of the nerve's complex anatomy, fiber-specific activation proves challenging. Spatially selective neuromodulation using micromagnetic stimulation(μMS) is showing incredible promise. This neuromodulation technique uses microcoils(μcoils) to generate magnetic fields by powering them with a time-varying current. Following the principles of Faraday's law of induction, a highly directional electric field is induced in the nerve from the magnetic field. In this study on rodent cervical vagus, a solenoidalμcoil was oriented at an angle to left and right branches of the nerve. The aim of this study was to measure changes in the mean arterial pressure (MAP) and heart rate (HR) followingμMS of the vagus. Theμcoils were powered by a single-cycle sinusoidal current varying in pulse widths(PW = 100, 500, and 1000μsec) at a frequency of 20 Hz. Under the influence of isoflurane,μMS of the left vagus at 1000μsec PW led to an average drop in MAP of 16.75 mmHg(n = 7). In contrast,μMS of the right vagus under isoflurane resulted in an average drop of 11.93 mmHg in the MAP(n = 7). Surprisingly, there were no changes in HR to either right or left vagalμMS suggesting the drop in MAP associated with vagusμMS was the result of stimulation of afferent, but not efferent fibers. In urethane anesthetized rats, no changes in either MAP or HR were observed uponμMS of the right or left vagus(n = 3). These findings suggest the choice of anesthesia plays a key role in determining the efficacy ofμMS on the vagal nerve. Absence of HR modulation uponμMS could offer alternative treatment options using VNS with fewer heart-related side-effects.
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Affiliation(s)
- Renata Saha
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States of America
| | - Dusty Van Helden
- Department of Surgery, University of Minnesota, Minneapolis, MN, United States of America
| | - Matthew S Hopper
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States of America
| | - Walter C Low
- Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States of America
| | - Theoden I Netoff
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States of America
| | - John Osborn
- Department of Surgery, University of Minnesota, Minneapolis, MN, United States of America
| | - Jian-Ping Wang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States of America
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Wernisch L, Edwards T, Berthon A, Tessier-Lariviere O, Sarkans E, Stoukidi M, Fortier-Poisson P, Pinkney M, Thornton M, Hanley C, Lee S, Jennings J, Appleton B, Garsed P, Patterson B, Buttinger W, Gonshaw S, Jakopec M, Shunmugam S, Mamen J, Tukiainen A, Lajoie G, Armitage O, Hewage E. Online Bayesian optimization of vagus nerve stimulation. J Neural Eng 2024; 21:026019. [PMID: 38479016 DOI: 10.1088/1741-2552/ad33ae] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/13/2024] [Indexed: 04/04/2024]
Abstract
Objective.In bioelectronic medicine, neuromodulation therapies induce neural signals to the brain or organs, modifying their function. Stimulation devices capable of triggering exogenous neural signals using electrical waveforms require a complex and multi-dimensional parameter space to control such waveforms. Determining the best combination of parameters (waveform optimization or dosing) for treating a particular patient's illness is therefore challenging. Comprehensive parameter searching for an optimal stimulation effect is often infeasible in a clinical setting due to the size of the parameter space. Restricting this space, however, may lead to suboptimal therapeutic results, reduced responder rates, and adverse effects.Approach. As an alternative to a full parameter search, we present a flexible machine learning, data acquisition, and processing framework for optimizing neural stimulation parameters, requiring as few steps as possible using Bayesian optimization. This optimization builds a model of the neural and physiological responses to stimulations, enabling it to optimize stimulation parameters and provide estimates of the accuracy of the response model. The vagus nerve (VN) innervates, among other thoracic and visceral organs, the heart, thus controlling heart rate (HR), making it an ideal candidate for demonstrating the effectiveness of our approach.Main results.The efficacy of our optimization approach was first evaluated on simulated neural responses, then applied to VN stimulation intraoperatively in porcine subjects. Optimization converged quickly on parameters achieving target HRs and optimizing neural B-fiber activations despite high intersubject variability.Significance.An optimized stimulation waveform was achieved in real time with far fewer stimulations than required by alternative optimization strategies, thus minimizing exposure to side effects. Uncertainty estimates helped avoiding stimulations outside a safe range. Our approach shows that a complex set of neural stimulation parameters can be optimized in real-time for a patient to achieve a personalized precision dosing.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Guillaume Lajoie
- Université de Montréal and Mila-Quebec AI Institute, Montréal, Canada
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10
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Peterson D, Van Poppel M, Boling W, Santos P, Schwalb J, Eisenberg H, Mehta A, Spader H, Botros J, Vrionis FD, Ko A, Adelson PD, Lega B, Konrad P, Calle G, Vale FL, Bucholz R, Richardson RM. Clinical safety and feasibility of a novel implantable neuroimmune modulation device for the treatment of rheumatoid arthritis: initial results from the randomized, double-blind, sham-controlled RESET-RA study. Bioelectron Med 2024; 10:8. [PMID: 38475923 PMCID: PMC10935935 DOI: 10.1186/s42234-023-00138-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 12/12/2023] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that causes persistent synovitis, bone damage, and progressive joint destruction. Neuroimmune modulation through electrical stimulation of the vagus nerve activates the inflammatory reflex and has been shown to inhibit the production and release of inflammatory cytokines and decrease clinical signs and symptoms in RA. The RESET-RA study was designed to determine the safety and efficacy of an active implantable device for treating RA. METHODS The RESET-RA study is a randomized, double-blind, sham-controlled, multi-center, two-stage pivotal trial that enrolled patients with moderate-to-severe RA who were incomplete responders or intolerant to at least one biologic or targeted synthetic disease-modifying anti-rheumatic drug. A neuroimmune modulation device (SetPoint Medical, Valencia, CA) was implanted on the left cervical vagus nerve within the carotid sheath in all patients. Following post-surgical clearance, patients were randomly assigned (1:1) to active stimulation or non-active (control) stimulation for 1 min once per day. A predefined blinded interim analysis was performed in patients enrolled in the study's initial stage (Stage 1) that included demographics, enrollment rates, device implantation rates, and safety of the surgical procedure, device, and stimulation over 12 weeks of treatment. RESULTS Sixty patients were implanted during Stage 1 of the study. All device implant procedures were completed without intraoperative complications, infections, or surgical revisions. No unanticipated adverse events were reported during the perioperative period and at the end of 12 weeks of follow-up. No study discontinuations were due to adverse events, and no serious adverse events were related to the device or stimulation. Two serious adverse events were related to the implantation procedure: vocal cord paresis and prolonged hoarseness. These were reported in two patients and are known complications of surgical implantation procedures with vagus nerve stimulation devices. The adverse event of vocal cord paresis resolved after vocal cord augmentation injections with filler and speech therapy. The prolonged hoarseness had improved with speech therapy, but mild hoarseness persists. CONCLUSIONS The surgical procedures for implantation of the novel neuroimmune modulation device for the treatment of RA were safe, and the device and its use were well tolerated. TRIAL REGISTRATION NCT04539964; August 31, 2020.
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Affiliation(s)
- Daniel Peterson
- Neurosurgery, Austin Neurosurgeons (Arise Medical Center), Austin, TX, USA
| | - Mark Van Poppel
- Neurosurgery, Carolina Neurosurgery & Spine Associates, Charlotte, NC, USA
| | - Warren Boling
- Neurosurgery, Loma Linda University Health, Loma Linda, CA, USA
| | - Perry Santos
- Integris Health Baptist Medical Center, Head and Neck Surgery, Oklahoma City, OK, USA
| | - Jason Schwalb
- Neurosurgery, Henry Ford Medical Group, Detroit, MI, USA
| | - Howard Eisenberg
- Neurosurgery, University of Maryland Medical Center, Baltimore, MD, USA
| | - Ashesh Mehta
- The Feinstein Institutes for Medical Research, Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, USA
| | - Heather Spader
- Neurosurgery, University of Virginia, Charlottesville, VA, USA
| | - James Botros
- Neurosurgery, University of New Mexico, Albuquerque, NM, USA
| | - Frank D Vrionis
- Neurosurgery, Marcus Neuroscience Institute, Boca Raton, FL, USA
| | - Andrew Ko
- Neurosurgery, University of Washington, Seattle, WA, USA
| | - P David Adelson
- Neurosurgery, Phoenix Children's Hospital, Phoenix, AZ, USA
- Rockefeller Neuroscience Institute, Neurosurgery, West Virginia University Medicine, Morgantown, WV, USA
| | - Bradley Lega
- Neurological Surgery, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Peter Konrad
- Rockefeller Neuroscience Institute, Neurosurgery, West Virginia University Medicine, Morgantown, WV, USA
| | | | - Fernando L Vale
- Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Richard Bucholz
- Division of Neurological Surgery, St. Louis University, St. Louis, MO, USA
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11
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Thompson N, Ravagli E, Mastitskaya S, Challita R, Hadaya J, Iacoviello F, Shah Idil A, Shearing PR, Ajijola OA, Ardell JL, Shivkumar K, Holder D, Aristovich K. Anatomical and functional organization of cardiac fibers in the porcine cervical vagus nerve allows spatially selective efferent neuromodulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574861. [PMID: 38260584 PMCID: PMC10802425 DOI: 10.1101/2024.01.09.574861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Cardiac disease progression reflects the dynamic interaction between adversely remodeled neurohumoral control systems and an abnormal cardiac substrate. Vagal nerve stimulation (VNS) is an attractive neuromodulatory option to dampen this dynamic interaction; however, it is limited by off-target effects. Spatially-selective VNS (sVNS) offers a promising solution to induce cardioprotection while mitigating off-target effects by specifically targeting pre-ganglionic parasympathetic efferent cardiac fibers. This approach also has the potential to enhance therapeutic outcomes by eliminating time-consuming titration required for optimal VNS. Recent studies have demonstrated the independent modulation of breathing rate, heart rate, and laryngeal contraction through sVNS. However, the spatial organization of afferent and efferent cardiac-related fibers within the vagus nerve remains unexplored. By using trial-and-error sVNS in vivo in combination with ex vivo micro-computed tomography fascicle tracing, we show the significant spatial separation of cardiac afferent and efferent fibers (179±55° SD microCT, p<0.05 and 200±137° SD, p<0.05 sVNS - degrees of separation across a cross-section of nerve) at the mid-cervical level. We also show that cardiac afferent fibers are located in proximity to pulmonary fibers consistent with recent findings of cardiopulmonary convergent neurons and circuits. We demonstrate the ability of sVNS to selectively elicit desired scalable heart rate decrease without stimulating afferent-related reflexes. By elucidating the spatial organization of cardiac-related fibers within the vagus nerve, our findings pave the way for more targeted neuromodulation, thereby reducing off-target effects and eliminating the need for titration. This, in turn, will enhance the precision and efficacy of VNS therapy in treating cardiac pathology, allowing for improved therapeutic efficacy.
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Affiliation(s)
- Nicole Thompson
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Enrico Ravagli
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Svetlana Mastitskaya
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Ronald Challita
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Joseph Hadaya
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Francesco Iacoviello
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, United Kingdom
| | - Ahmad Shah Idil
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Paul R. Shearing
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, United Kingdom
| | - Olujimi A. Ajijola
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jeffrey L. Ardell
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - David Holder
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Kirill Aristovich
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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12
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Paterson DJ, Shivkumar K. Bioelectronics for neurocardiology: diagnosis and therapeutics. Eur Heart J 2023; 44:4822-4825. [PMID: 37949823 DOI: 10.1093/eurheartj/ehad624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2023] Open
Affiliation(s)
- David J Paterson
- Burdon Sanderson Cardiac Science Centre, Sherrington Building, Department of Physiology, Anatomy & Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Kalyanam Shivkumar
- Department of Medicine, UCLA Cardiac Arrhythmia Center University of California, Los Angeles, 100 UCLA Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
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13
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Wang L, Gao F, Wang Z, Liang F, Dai Y, Wang M, Wu J, Chen Y, Yan Q, Wang L. Transcutaneous auricular vagus nerve stimulation in the treatment of disorders of consciousness: mechanisms and applications. Front Neurosci 2023; 17:1286267. [PMID: 37920298 PMCID: PMC10618368 DOI: 10.3389/fnins.2023.1286267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/05/2023] [Indexed: 11/04/2023] Open
Abstract
This review provides an in-depth exploration of the mechanisms and applications of transcutaneous auricular vagus nerve stimulation (taVNS) in treating disorders of consciousness (DOC). Beginning with an exploration of the vagus nerve's role in modulating brain function and consciousness, we then delve into the neuroprotective potential of taVNS demonstrated in animal models. The subsequent sections assess the therapeutic impact of taVNS on human DOC, discussing the safety, tolerability, and various factors influencing the treatment response. Finally, the review identifies the current challenges in taVNS research and outlines future directions, emphasizing the need for large-scale trials, optimization of treatment parameters, and comprehensive investigation of taVNS's long-term effects and underlying mechanisms. This comprehensive overview positions taVNS as a promising and safe modality for DOC treatment, with a focus on understanding its intricate neurophysiological influence and optimizing its application in clinical settings.
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Affiliation(s)
- Likai Wang
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
| | - Fei Gao
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
| | - Zhan Wang
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
| | - Feng Liang
- First Clinical Medical College, Shanxi Medical University, Taiyuan, China
| | - Yongli Dai
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
| | - Mengchun Wang
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
| | - Jingyi Wu
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
| | - Yaning Chen
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
| | - Qinjie Yan
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
| | - Litong Wang
- Department of Rehabilitation Medicine, The Second Hospital of Dalian Medical University, Dalian, China
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14
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Wang J, Zhang Q, Yao L, He T, Chen X, Su Y, Sun S, Fan M, Yan J, Wang T, Zhang M, Guo F, Mo S, Lu M, Zou M, Li L, Yuan Q, Pan H, Chen Y. Modulating activity of PVN neurons prevents atrial fibrillation induced circulation dysfunction by electroacupuncture at BL15. Chin Med 2023; 18:135. [PMID: 37848944 PMCID: PMC10580609 DOI: 10.1186/s13020-023-00841-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 09/20/2023] [Indexed: 10/19/2023] Open
Abstract
BACKGROUND Circulation dysfunction is a major contributing factor to thrombosis in patients with atrial fibrillation (AF) for which effective interventions are lacking. Growing evidence indicates that regulating the paraventricular nucleus (PVN), an autonomic control center, could offer a novel strategy for treating cardiovascular and circulatory diseases. Concurrently, electroacupuncture (EA) at Xinshu (BL15), a form of peripheral nerve stimulation, has shown efficacy in treating several cardiovascular conditions, although its specific mechanism remains unclear. This study aimed to assess the impact of EA at BL15 on circulatory dysfunction in a rat AF model and investigate the pivotal role of PVN neuronal activity. METHODS To mimic the onset of AF, male SD rats received tail intravenous injection of ACh-CaCl2 and were then subjected to EA at BL15, sham EA, or EA at Shenshu (BL23). Macro- and micro-circulation function were evaluated using in vivo ultrasound imaging and laser doppler testing, respectively. Vasomotricity was assessed by measuring dimension changes during vascular relaxation and contraction. Vascular endothelial function was measured using myograph, and the activation of the autonomic nerve system was evaluated through nerve activity signals. Additionally, chemogenetic manipulation was used to block PVN neuronal activation to further elucidate the role of PVN activation in the prevention of AF-induced blood circulation dysfunction through EA treatment. RESULTS Our data demonstrate that EA at BL15, but not BL23 or sham EA, effectively prevented AF-induced macro- and micro-circulation dysfunction. Furthermore, EA at BL15 restored AF-induced vasomotricity impairment. Additionally, EA treatment prevented abnormal activation of the autonomic nerve system induced by AF, although it did not address vascular endothelial dysfunction. Importantly, excessive activation of PVN neurons negated the protective effects of EA treatment on AF-induced circulation dysfunction in rats. CONCLUSION These results indicate that EA treatment at BL15 modulates PVN neuronal activity and provides protection against AF-induced circulatory dysfunction.
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Affiliation(s)
- Jingya Wang
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Qiumei Zhang
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Institute of Physical and Health, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Guangdong Chaozhou Health Vocational College, Chaozhou, 521000, People's Republic of China
| | - Lin Yao
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Teng He
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China
| | - Xinyi Chen
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Yang Su
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Shengxuan Sun
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Mengyue Fan
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China
| | - Jinglan Yan
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China
| | - Taiyi Wang
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China
| | - Meng Zhang
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China
| | - Feng Guo
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China
| | - Shiqing Mo
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Manqi Lu
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Meixia Zou
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Liangjie Li
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Qing Yuan
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Huashan Pan
- Institute of Physical and Health, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China.
- Guangdong Chaozhou Health Vocational College, Chaozhou, 521000, People's Republic of China.
| | - Yongjun Chen
- Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, People's Republic of China.
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China.
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15
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Hadaya J, Dajani AH, Cha S, Hanna P, Challita R, Hoover DB, Ajijola OA, Shivkumar K, Ardell JL. Vagal Nerve Stimulation Reduces Ventricular Arrhythmias and Mitigates Adverse Neural Cardiac Remodeling Post-Myocardial Infarction. JACC Basic Transl Sci 2023; 8:1100-1118. [PMID: 37791302 PMCID: PMC10543930 DOI: 10.1016/j.jacbts.2023.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/29/2023] [Accepted: 03/29/2023] [Indexed: 10/05/2023]
Abstract
This study sought to evaluate the impact of chronic vagal nerve stimulation (cVNS) on cardiac and extracardiac neural structure/function after myocardial infarction (MI). Groups were control, MI, and MI + cVNS; cVNS was started 2 days post-MI. Terminal experiments were performed 6 weeks post-MI. MI impaired left ventricular mechanical function, evoked anisotropic electrical conduction, increased susceptibility to ventricular tachycardia and fibrillation, and altered neuronal and glial phenotypes in the stellate and dorsal root ganglia, including glial activation. cVNS improved cardiac mechanical function and reduced ventricular tachycardia/ventricular fibrillation post-MI, partly by stabilizing activation/repolarization in the border zone. MI-associated extracardiac neural remodeling, particularly glial activation, was mitigated with cVNS.
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Affiliation(s)
- Joseph Hadaya
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
| | - Al-Hassan Dajani
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Steven Cha
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Peter Hanna
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
| | - Ronald Challita
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Donald B. Hoover
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
- Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee, USA
| | - Olujimi A. Ajijola
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
| | - Jeffrey L. Ardell
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, California, USA
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16
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van Weperen VYH, Ripplinger CM, Vaseghi M. Autonomic control of ventricular function in health and disease: current state of the art. Clin Auton Res 2023; 33:491-517. [PMID: 37166736 PMCID: PMC10173946 DOI: 10.1007/s10286-023-00948-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/20/2023] [Indexed: 05/12/2023]
Abstract
PURPOSE Cardiac autonomic dysfunction is one of the main pillars of cardiovascular pathophysiology. The purpose of this review is to provide an overview of the current state of the art on the pathological remodeling that occurs within the autonomic nervous system with cardiac injury and available neuromodulatory therapies for autonomic dysfunction in heart failure. METHODS Data from peer-reviewed publications on autonomic function in health and after cardiac injury are reviewed. The role of and evidence behind various neuromodulatory therapies both in preclinical investigation and in-use in clinical practice are summarized. RESULTS A harmonic interplay between the heart and the autonomic nervous system exists at multiple levels of the neuraxis. This interplay becomes disrupted in the setting of cardiovascular disease, resulting in pathological changes at multiple levels, from subcellular cardiac signaling of neurotransmitters to extra-cardiac, extra-thoracic remodeling. The subsequent detrimental cycle of sympathovagal imbalance, characterized by sympathoexcitation and parasympathetic withdrawal, predisposes to ventricular arrhythmias, progression of heart failure, and cardiac mortality. Knowledge on the etiology and pathophysiology of this condition has increased exponentially over the past few decades, resulting in a number of different neuromodulatory approaches. However, significant knowledge gaps in both sympathetic and parasympathetic interactions and causal factors that mediate progressive sympathoexcitation and parasympathetic dysfunction remain. CONCLUSIONS Although our understanding of autonomic imbalance in cardiovascular diseases has significantly increased, specific, pivotal mediators of this imbalance and the recognition and implementation of available autonomic parameters and neuromodulatory therapies are still lagging.
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Affiliation(s)
- Valerie Y H van Weperen
- Division of Cardiology, Department of Medicine, UCLA Cardiac Arrythmia Center, University of California, 100 Medical Plaza, Suite 660, Los Angeles, CA, 90095, USA
| | | | - Marmar Vaseghi
- Division of Cardiology, Department of Medicine, UCLA Cardiac Arrythmia Center, University of California, 100 Medical Plaza, Suite 660, Los Angeles, CA, 90095, USA.
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17
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Wu Z, Liao J, Liu Q, Zhou S, Chen M. Chronic vagus nerve stimulation in patients with heart failure: challenge or failed translation? Front Cardiovasc Med 2023; 10:1052471. [PMID: 37534273 PMCID: PMC10390725 DOI: 10.3389/fcvm.2023.1052471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 05/31/2023] [Indexed: 08/04/2023] Open
Abstract
Autonomic imbalance between the sympathetic and parasympathetic nervous systems contributes to the progression of chronic heart failure (HF). Preclinical studies have demonstrated that various neuromodulation strategies may exert beneficial cardioprotective effects in preclinical models of HF. Based on these encouraging experimental data, vagus nerve stimulation (VNS) has been assessed in patients with HF with a reduced ejection fraction. Nevertheless, the main trials conducted thus far have yielded conflicting findings, questioning the clinical efficacy of VNS in this context. This review will therefore focus on the role of the autonomic nervous system in HF pathophysiology and VNS therapy, highlighting the potential reasons behind the discrepancy between preclinical and clinical studies.
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Affiliation(s)
- Zhihong Wu
- Department of Cardiovascular, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Jiaying Liao
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Qiming Liu
- Department of Cardiovascular, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Shenghua Zhou
- Department of Cardiovascular, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Mingxian Chen
- Department of Cardiovascular, The Second Xiangya Hospital of Central South University, Changsha, China
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18
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Arya AV, Bisht H, Tripathi A, Agrawal M, Konat A, Patel J, Mozumder K, Shah D, Chaturvedi D, Sharma K. A Comparative Review of Vagal Nerve Stimulation Versus Baroreceptor Activation Therapy in Cardiac Diseases. Cureus 2023; 15:e40889. [PMID: 37492836 PMCID: PMC10364457 DOI: 10.7759/cureus.40889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2023] [Indexed: 07/27/2023] Open
Abstract
Sympathetic imbalance coupled with impairment of baroreceptor control is a key factor responsible for hemodynamic abnormalities in congestive heart failure. Vagal nerve stimulation (VNS) and baroreceptor activation therapy (BAT) are two novel interventions for the same. In this paper, we review the role of sympathovagal alterations in cardiac diseases like heart failure, arrhythmia, hypertension (HTN), etc. Studies like neural cardiac therapy for heart failure (NECTAR-HF), autonomic regulation therapy to enhance myocardial function and reduce progression of heart failure (ANTHEM-HF), and baroreflex activation therapy for heart failure (BEAT-HF), which comprise the history, efficacy, limitations, and current protocols, were extensively analyzed in contrast to one another. Vagal nerve stimulation reverses the reflex inhibition of cardiac vagal efferent activity, which is caused as a result of sympathetic overdrive during the course for heart failure. It has shown encouraging results in certain pre-clinical studies; however, there is also a possibility of serious cardiovascular adverse events if given in higher than the recommended dosage. Attenuated baroreflex sensitivity is attributed to cardiac arrhythmogenesis during heart failure. Baroreceptor activation therapy reverses this phenomenon. However, the surgical procedure for baroreceptor stimulation can have unwarranted complications, including worsening heart failure and hypertension. Considering the effectiveness of the given modalities and taking into account the inconclusive evidence of their adverse events, more clinical trials are needed for establishing the future prospects of these interventional approaches.
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Affiliation(s)
- Akshat V Arya
- Internal Medicine, Byramjee Jeejeebhoy Medical College, Ahmedabad, IND
| | - Himanshi Bisht
- Medicine, Byramjee Jeejeebhoy Medical College, Ahmedabad, IND
| | | | - Manali Agrawal
- Internal Medicine, Byramjee Jeejeebhoy Medical College, Ahmedabad, IND
| | - Ashwati Konat
- Zoology, Biomedical Technology and Human Genetics, Gujarat University, Ahmedabad, IND
| | - Jay Patel
- Internal Medicine, Byramjee Jeejeebhoy Medical College, Ahmedabad, IND
| | - Kamalika Mozumder
- Internal Medicine, Byramjee Jeejeebhoy Medical College, Ahmedabad, IND
| | - Dhrumil Shah
- Internal Medicine, Gujarat Medical Education and Research Society Medical College, Gandhinagar, IND
| | | | - Kamal Sharma
- Cardiology, Kamal Sharma Cardiology Clinic, Ahmedabad, IND
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19
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Habibagahi I, Jang J, Babakhani A. Miniaturized Wirelessly Powered and Controlled Implants for Multisite Stimulation. IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2023; 71:1911-1922. [PMID: 38645708 PMCID: PMC11031205 DOI: 10.1109/tmtt.2022.3233368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
This paper presents a miniaturized implant with a diameter of only 14 mm, which houses a novel System on Chip (SoC) enabling two voltage level stimulation of up to 16 implants using a single Tx coil. Each implant can operate at a distance of 80 mm in the air through the inductive resonant link. The SoC consumes only 27 μW static power and enables two channels with stimulation amplitudes of 1.8 V and 3.3 V and timing resolution of 100 μs. The SoC is implemented in the standard 180 nm complementary metal oxide semiconductor (CMOS) technology and has an area of 0.75 mm × 1.6 mm. The SoC comprises an RF rectifier, low drop-out regulator (LDO), error detection block, clock data recovery, finite state machine (FSM), and output stage. Each implant has a PCB-defined passcode, which enables the individual addressability of the implants for synchronized therapies. The implantable device weighs only 80 mg and sizes 20.1 mm3. Tolerance of up to 70° to angular misalignment was measured at a distance of 50 mm. The efficacy of bilateral stimulation was further verified by implanting two devices on two sides of a pig's neck and performing bilateral vagus nerve stimulation (VNS), while monitoring the heart rate.
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Affiliation(s)
- Iman Habibagahi
- Department of Electrical Engineering, University of California, Los Angeles, CA 90095 USA
| | - Jaeeun Jang
- Department of Electrical Engineering, University of California, Los Angeles, CA 90095 USA
| | - Aydin Babakhani
- Department of Electrical Engineering, University of California, Los Angeles, CA 90095 USA
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20
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Gee MM, Hornung E, Gupta S, Newton AJH, Cheng ZJ, Lytton WW, Lenhoff AM, Schwaber JS, Vadigepalli R. Unpacking the multimodal, multi-scale data of the fast and slow lanes of the cardiac vagus through computational modelling. Exp Physiol 2023:10.1113/EP090865. [PMID: 37120805 PMCID: PMC10613580 DOI: 10.1113/ep090865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 04/12/2023] [Indexed: 05/01/2023]
Abstract
NEW FINDINGS What is the topic of this review? The vagus nerve is a crucial regulator of cardiovascular homeostasis, and its activity is linked to heart health. Vagal activity originates from two brainstem nuclei: the nucleus ambiguus (fast lane) and the dorsal motor nucleus of the vagus (slow lane), nicknamed for the time scales that they require to transmit signals. What advances does it highlight? Computational models are powerful tools for organizing multi-scale, multimodal data on the fast and slow lanes in a physiologically meaningful way. A strategy is laid out for how these models can guide experiments aimed at harnessing the cardiovascular health benefits of differential activation of the fast and slow lanes. ABSTRACT The vagus nerve is a key mediator of brain-heart signaling, and its activity is necessary for cardiovascular health. Vagal outflow stems from the nucleus ambiguus, responsible primarily for fast, beat-to-beat regulation of heart rate and rhythm, and the dorsal motor nucleus of the vagus, responsible primarily for slow regulation of ventricular contractility. Due to the high-dimensional and multimodal nature of the anatomical, molecular and physiological data on neural regulation of cardiac function, data-derived mechanistic insights have proven elusive. Elucidating insights has been complicated further by the broad distribution of the data across heart, brain and peripheral nervous system circuits. Here we lay out an integrative framework based on computational modelling for combining these disparate and multi-scale data on the two vagal control lanes of the cardiovascular system. Newly available molecular-scale data, particularly single-cell transcriptomic analyses, have augmented our understanding of the heterogeneous neuronal states underlying vagally mediated fast and slow regulation of cardiac physiology. Cellular-scale computational models built from these data sets represent building blocks that can be combined using anatomical and neural circuit connectivity, neuronal electrophysiology, and organ/organismal-scale physiology data to create multi-system, multi-scale models that enable in silico exploration of the fast versus slow lane vagal stimulation. The insights from the computational modelling and analyses will guide new experimental questions on the mechanisms regulating the fast and slow lanes of the cardiac vagus toward exploiting targeted vagal neuromodulatory activity to promote cardiovascular health.
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Affiliation(s)
- Michelle M Gee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA
- Department of Pathology and Genomic Medicine, Daniel Baugh Institute of Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Eden Hornung
- Department of Pathology and Genomic Medicine, Daniel Baugh Institute of Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Suranjana Gupta
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Adam J H Newton
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Zixi Jack Cheng
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - William W Lytton
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Abraham M Lenhoff
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA
| | - James S Schwaber
- Department of Pathology and Genomic Medicine, Daniel Baugh Institute of Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Rajanikanth Vadigepalli
- Department of Pathology and Genomic Medicine, Daniel Baugh Institute of Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, PA, USA
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21
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Verma N, Knudsen B, Gholston A, Skubal A, Blanz S, Settell M, Frank J, Trevathan J, Ludwig K. Microneurography as a minimally invasive method to assess target engagement during neuromodulation. J Neural Eng 2023; 20:10.1088/1741-2552/acc35c. [PMID: 36898148 PMCID: PMC10587909 DOI: 10.1088/1741-2552/acc35c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 03/10/2023] [Indexed: 03/12/2023]
Abstract
Objective.Peripheral neural signals recorded during neuromodulation therapies provide insights into local neural target engagement and serve as a sensitive biomarker of physiological effect. Although these applications make peripheral recordings important for furthering neuromodulation therapies, the invasive nature of conventional nerve cuffs and longitudinal intrafascicular electrodes (LIFEs) limit their clinical utility. Furthermore, cuff electrodes typically record clear asynchronous neural activity in small animal models but not in large animal models. Microneurography, a minimally invasive technique, is already used routinely in humans to record asynchronous neural activity in the periphery. However, the relative performance of microneurography microelectrodes compared to cuff and LIFE electrodes in measuring neural signals relevant to neuromodulation therapies is not well understood.Approach.To address this gap, we recorded cervical vagus nerve electrically evoked compound action potentials (ECAPs) and spontaneous activity in a human-scaled large animal model-the pig. Additionally, we recorded sensory evoked activity and both invasively and non-invasively evoked CAPs from the great auricular nerve. In aggregate, this study assesses the potential of microneurography electrodes to measure neural activity during neuromodulation therapies with statistically powered and pre-registered outcomes (https://osf.io/y9k6j).Main results.The cuff recorded the largest ECAP signal (p< 0.01) and had the lowest noise floor amongst the evaluated electrodes. Despite the lower signal to noise ratio, microneurography electrodes were able to detect the threshold for neural activation with similar sensitivity to cuff and LIFE electrodes once a dose-response curve was constructed. Furthermore, the microneurography electrodes recorded distinct sensory evoked neural activity.Significance.The results show that microneurography electrodes can measure neural signals relevant to neuromodulation therapies. Microneurography could further neuromodulation therapies by providing a real-time biomarker to guide electrode placement and stimulation parameter selection to optimize local neural fiber engagement and study mechanisms of action.
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Affiliation(s)
- Nishant Verma
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Bruce Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Aaron Gholston
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Aaron Skubal
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Stephan Blanz
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Megan Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Jennifer Frank
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
| | - James Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Kip Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
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22
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Gee MM, Lenhoff AM, Schwaber JS, Ogunnaike BA, Vadigepalli R. Closed-loop modeling of central and intrinsic cardiac nervous system circuits underlying cardiovascular control. AIChE J 2023; 69:e18033. [PMID: 37250861 PMCID: PMC10211393 DOI: 10.1002/aic.18033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/02/2023] [Indexed: 01/16/2023]
Abstract
The baroreflex is a multi-input, multi-output control physiological system that regulates blood pressure by modulating nerve activity between the brainstem and the heart. Existing computational models of the baroreflex do not explictly incorporate the intrinsic cardiac nervous system (ICN), which mediates central control of the heart function. We developed a computational model of closed-loop cardiovascular control by integrating a network representation of the ICN within central control reflex circuits. We examined central and local contributions to the control of heart rate, ventricular functions, and respiratory sinus arrhythmia (RSA). Our simulations match the experimentally observed relationship between RSA and lung tidal volume. Our simulations predicted the relative contributions of the sensory and the motor neuron pathways to the experimentally observed changes in the heart rate. Our closed-loop cardiovascular control model is primed for evaluating bioelectronic interventions to treat heart failure and renormalize cardiovascular physiology.
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Affiliation(s)
- Michelle M Gee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716
- Daniel Baugh Institute of Functional Genomics/Computational Biology, Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, PA 19107
| | - Abraham M Lenhoff
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716
| | - James S Schwaber
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716
- Daniel Baugh Institute of Functional Genomics/Computational Biology, Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, PA 19107
| | - Babatunde A Ogunnaike
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716
| | - Rajanikanth Vadigepalli
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716
- Daniel Baugh Institute of Functional Genomics/Computational Biology, Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, PA 19107
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23
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Soltani D, Stavrakis S. Neuromodulation for the Management of Atrial Fibrillation—How to Optimize Patient Selection and the Procedural Approach. CURRENT CARDIOVASCULAR RISK REPORTS 2023. [DOI: 10.1007/s12170-023-00718-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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24
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Kumar HU, Nearing BD, Mittal S, Premchand RK, Libbus I, DiCarlo LA, Amurthur B, KenKnight BH, Anand IS, Verrier RL. Autonomic regulation therapy in chronic heart failure with preserved/mildly reduced ejection fraction: ANTHEM-HFpEF study results. Int J Cardiol 2023; 381:37-44. [PMID: 36934987 DOI: 10.1016/j.ijcard.2023.03.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/08/2023] [Accepted: 03/13/2023] [Indexed: 03/21/2023]
Abstract
BACKGROUND Autonomic regulation therapy (ART) utilizing cervical vagus nerve stimulation (VNS) appeared to be safe and to improve autonomic tone, symptoms, and cardiac mechanical function in patients with symptomatic heart failure and reduced ejection fraction in the ANTHEM-HF Study. The ANTHEM-HFpEF Study is the first investigation to evaluate the safety and feasibility of ART in patients with symptomatic heart failure and preserved or mildly reduced ejection fraction (HFpEF, HFmrEF). METHODS This open-label interventional study enrolled 52 patients with HFpEF or HFmrEF, NYHA Class II-III, and LVEF ≥40%, who received stable guideline-directed medical therapy. All patients were successfully implanted with LivaNova VNS Therapy® system with an electrical lead surrounding the right cervical vagus nerve. RESULTS Adverse event incidence was low. At 12 months, NYHA class (p < 0.0001), 6-min walk distance (p < 0.05), and quality of life (p < 0.0001) were improved. Cardiac mechanical function measures were normal at baseline, except for left ventricular mass index in women and E/e' ratio in all patients, which were elevated at baseline, and were unchanged by ART. Autonomic tone and reflexes improved, indicated by 29% decrease in low-frequency/high-frequency heart rate variability to normal levels (p = 0.028) and by increased heart rate turbulence slope (p = 0.047). T-wave alternans (p = 0.001) and T-wave heterogeneity (p = 0.001) were reduced from abnormal to normal ranges. Nonsustained ventricular tachycardia incidence decreased (p = 0.027). CONCLUSIONS ART appeared well-tolerated and safe in patients with HFpEF or HFmrEF. Chronic ART did not alter mechanical function measures but was associated with improved heart failure symptoms, exercise tolerance, autonomic tone, and cardiac electrical stability. CLINICAL TRIAL REGISTRY Autonomic Neural Regulation Therapy to Enhance Myocardial Function in Heart Failure with Preserved Ejection Fraction [ClinicalTrials.gov #NCT03163030, registered 05/22/2017].
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Affiliation(s)
| | - Bruce D Nearing
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | | | | | | | | | | | | | - Richard L Verrier
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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25
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Blanz SL, Musselman ED, Settell ML, Knudsen BE, Nicolai EN, Trevathan JK, Verner RS, Begnaud J, Skubal AC, Suminski AJ, Williams JC, Shoffstall AJ, Grill WM, Pelot NA, Ludwig KA. Spatially selective stimulation of the pig vagus nerve to modulate target effect versus side effect. J Neural Eng 2023; 20:10.1088/1741-2552/acb3fd. [PMID: 36649655 PMCID: PMC10339030 DOI: 10.1088/1741-2552/acb3fd] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/17/2023] [Indexed: 01/18/2023]
Abstract
Electrical stimulation of the cervical vagus nerve using implanted electrodes (VNS) is FDA-approved for the treatment of drug-resistant epilepsy, treatment-resistant depression, and most recently, chronic ischemic stroke rehabilitation. However, VNS is critically limited by the unwanted stimulation of nearby neck muscles-a result of non-specific stimulation activating motor nerve fibers within the vagus. Prior studies suggested that precise placement of small epineural electrodes can modify VNS therapeutic effects, such as cardiac responses. However, it remains unclear if placement can alter the balance between intended effect and limiting side effect. We used an FDA investigational device exemption approved six-contact epineural cuff to deliver VNS in pigs and quantified how epineural electrode location impacts on- and off-target VNS activation. Detailed post-mortem histology was conducted to understand how the underlying neuroanatomy impacts observed functional responses. Here we report the discovery and characterization of clear neuroanatomy-dependent differences in threshold and saturation for responses related to both effect (change in heart rate) and side effect (neck muscle contractions). The histological and electrophysiological data were used to develop and validate subject-specific computation models of VNS, creating a well-grounded quantitative framework to optimize electrode location-specific activation of nerve fibers governing intended effect versus unwanted side effect.
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Affiliation(s)
- Stephan L Blanz
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
| | - Eric D Musselman
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Megan L Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Bruce E Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Evan N Nicolai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
- Mayo Clinic, Rochester, MN, United States of America
| | - James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Ryan S Verner
- LivaNova USA Inc., Houston, TX, United States of America
| | - Jason Begnaud
- LivaNova USA Inc., Houston, TX, United States of America
| | - Aaron C Skubal
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Aaron J Suminski
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Warren M Grill
- University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States of America
- Department of Neurobiology, Duke University, Durham, NC, United States of America
- Department of Neurosurgery, Duke University, Durham, NC, United States of America
| | - Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
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26
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Huffman WJ, Musselman ED, Pelot NA, Grill WM. Measuring and modeling the effects of vagus nerve stimulation on heart rate and laryngeal muscles. Bioelectron Med 2023; 9:3. [PMID: 36797733 PMCID: PMC9936668 DOI: 10.1186/s42234-023-00107-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 02/08/2023] [Indexed: 02/18/2023] Open
Abstract
BACKGROUND Reduced heart rate (HR) during vagus nerve stimulation (VNS) is associated with therapy for heart failure, but stimulation frequency and amplitude are limited by patient tolerance. An understanding of physiological responses to parameter adjustments would allow differential control of therapeutic and side effects. To investigate selective modulation of the physiological responses to VNS, we quantified the effects and interactions of parameter selection on two physiological outcomes: one related to therapy (reduced HR) and one related to side effects (laryngeal muscle EMG). METHODS We applied a broad range of stimulation parameters (mean pulse rates (MPR), intra-burst frequencies, and amplitudes) to the vagus nerve of anesthetized mice. We leveraged the in vivo recordings to parameterize and validate computational models of HR and laryngeal muscle activity across amplitudes and temporal patterns of VNS. We constructed a finite element model of excitation of fibers within the mouse cervical vagus nerve. RESULTS HR decreased with increased amplitude, increased MPR, and decreased intra-burst frequency. EMG increased with increased MPR. Preferential HR effects over laryngeal EMG effects required combined adjustments of amplitude and MPR. The model of HR responses highlighted contributions of ganglionic filtering to VNS-evoked changes in HR at high stimulation frequencies. Overlap in activation thresholds between small and large modeled fibers was consistent with the overlap in dynamic ranges of related physiological measures (HR and EMG). CONCLUSION The present study provides insights into physiological responses to VNS required for informed parameter adjustment to modulate selectively therapeutic effects and side effects.
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Affiliation(s)
- William J. Huffman
- grid.26009.3d0000 0004 1936 7961Department of Biomedical Engineering, Duke University, Fitzpatrick CIEMAS, Box 90281, Room 1427, 101 Science Drive, Durham, NC 27708-0281 USA
| | - Eric D. Musselman
- grid.26009.3d0000 0004 1936 7961Department of Biomedical Engineering, Duke University, Fitzpatrick CIEMAS, Box 90281, Room 1427, 101 Science Drive, Durham, NC 27708-0281 USA
| | - Nicole A. Pelot
- grid.26009.3d0000 0004 1936 7961Department of Biomedical Engineering, Duke University, Fitzpatrick CIEMAS, Box 90281, Room 1427, 101 Science Drive, Durham, NC 27708-0281 USA
| | - Warren M. Grill
- grid.26009.3d0000 0004 1936 7961Department of Biomedical Engineering, Duke University, Fitzpatrick CIEMAS, Box 90281, Room 1427, 101 Science Drive, Durham, NC 27708-0281 USA ,grid.26009.3d0000 0004 1936 7961Department of Electrical and Computer Engineering, Duke University, Durham, USA ,grid.26009.3d0000 0004 1936 7961Department of Neurobiology Engineering, Duke University, Durham, USA ,grid.26009.3d0000 0004 1936 7961Department of Neurosurgery Engineering, Duke University, Durham, USA
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27
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Jayaprakash N, Song W, Toth V, Vardhan A, Levy T, Tomaio J, Qanud K, Mughrabi I, Chang YC, Rob M, Daytz A, Abbas A, Nassrallah Z, Volpe BT, Tracey KJ, Al-Abed Y, Datta-Chaudhuri T, Miller L, Barbe MF, Lee SC, Zanos TP, Zanos S. Organ- and function-specific anatomical organization of vagal fibers supports fascicular vagus nerve stimulation. Brain Stimul 2023; 16:484-506. [PMID: 36773779 DOI: 10.1016/j.brs.2023.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 02/03/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023] Open
Abstract
Vagal fibers travel inside fascicles and form branches to innervate organs and regulate organ functions. Existing vagus nerve stimulation (VNS) therapies activate vagal fibers non-selectively, often resulting in reduced efficacy and side effects from non-targeted organs. The transverse and longitudinal arrangement of fibers inside the vagal trunk with respect to the functions they mediate and organs they innervate is unknown, however it is crucial for selective VNS. Using micro-computed tomography imaging, we tracked fascicular trajectories and found that, in swine, sensory and motor fascicles are spatially separated cephalad, close to the nodose ganglion, and merge caudad, towards the lower cervical and upper thoracic region; larynx-, heart- and lung-specific fascicles are separated caudad and progressively merge cephalad. Using quantified immunohistochemistry at single fiber level, we identified and characterized all vagal fibers and found that fibers of different morphological types are differentially distributed in fascicles: myelinated afferents and efferents occupy separate fascicles, myelinated and unmyelinated efferents also occupy separate fascicles, and small unmyelinated afferents are widely distributed within most fascicles. We developed a multi-contact cuff electrode to accommodate the fascicular structure of the vagal trunk and used it to deliver fascicle-selective cervical VNS in anesthetized and awake swine. Compound action potentials from distinct fiber types, and physiological responses from different organs, including laryngeal muscle, cough, breathing, and heart rate responses are elicited in a radially asymmetric manner, with consistent angular separations that agree with the documented fascicular organization. These results indicate that fibers in the trunk of the vagus nerve are anatomically organized according to functions they mediate and organs they innervate and can be asymmetrically activated by fascicular cervical VNS.
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Affiliation(s)
| | - Weiguo Song
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Viktor Toth
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | - Todd Levy
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | - Khaled Qanud
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | - Yao-Chuan Chang
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Moontahinaz Rob
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Anna Daytz
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
| | - Adam Abbas
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Zeinab Nassrallah
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
| | - Bruce T Volpe
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Kevin J Tracey
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Yousef Al-Abed
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | - Larry Miller
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | - Sunhee C Lee
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | - Stavros Zanos
- Feinstein Institutes for Medical Research, Manhasset, NY, USA; Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA; Elmezzi Graduate School of Molecular Medicine, Manhasset, NY, USA.
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28
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Hemodynamic responses to low-level transcutaneous auricular nerve stimulation in young volunteers. IBRO Neurosci Rep 2023; 14:154-159. [PMID: 36824666 PMCID: PMC9941060 DOI: 10.1016/j.ibneur.2023.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 01/29/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Objectives The aim of this study was to characterize cardiovascular autonomic responses during two constant current intensities below sensory threshold of transcutaneous auricular nerve stimulation (taNS). On this basis, a protocol for taNS with autonomic modulatory potential could be proposed. Subjects and methods We included 26 men and 24 women, mean age 26. Data were collected during three randomly allocated 20-minute right tragus stimulation sessions - a) no-stimulation (sham), b) 90 µA (arbitrary), and c) 130 µA (near the lowest sensory threshold in majority). Stimulation was 20 Hz, rectangular pulse width of 2 ms, duty cycle 2-second on/off. To assess autonomic responses, we continuously recorded ECG, non-invasive arterial blood pressure (BP) and thoracic impedance cardiography data. Ten-minute data were compared. Fast Fourier transform of RR intervals was performed on 10-minute recordings as well. Low frequency and high frequency power spectra were calculated. Friedman test or one-way ANOVA for repeated measurements and Mann-Whitney or Wilcoxon's signed-rank test, or t-test were carried out. P < 0.05 was considered significant. Results At 130 µA stimulation, cardiac output significantly decreased (p < 0.05), driven by significant heart rate drop in women, and stroke volume and contractility drop in men, pointing to a gender-related autonomic responses. We observed no significant changes in BP, or variability parameters. Significantly higher body size and BP were found in men, as expected. Conclusions It seems that tested taNS protocol has a potential for cardiac autonomic modulation in majority of young healthy men as well as women. Further studies are however needed to prove the therapeutic potential of this stimulation protocol in different patient groups.
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29
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Karatela MF, Fudim M, Mathew JP, Piccini JP. Neuromodulation therapy for atrial fibrillation. Heart Rhythm 2023; 20:100-111. [PMID: 35988908 DOI: 10.1016/j.hrthm.2022.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/07/2022] [Accepted: 08/12/2022] [Indexed: 02/08/2023]
Abstract
Atrial fibrillation has a multifactorial pathophysiology influenced by cardiac autonomic innervation. Both sympathetic and parasympathetic influences are profibrillatory. Innovative therapies targeting the neurocardiac axis include catheter ablation or pharmacologic suppression of ganglionated plexi, renal sympathetic denervation, low-level vagal stimulation, and stellate ganglion blockade. To date, these therapies have variable efficacy. As our understanding of atrial fibrillation and the cardiac nervous system expands, our approach to therapeutic neuromodulation will continue evolving for the benefit of those with AF.
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Affiliation(s)
- Maham F Karatela
- Cardiac Electrophysiology Section, Duke Heart Center and Department of Medicine, Duke University Medical Center, Durham, North Carolina; Duke Clinical Research Institute, Durham, North Carolina
| | - Marat Fudim
- Cardiac Electrophysiology Section, Duke Heart Center and Department of Medicine, Duke University Medical Center, Durham, North Carolina; Duke Clinical Research Institute, Durham, North Carolina
| | - Joseph P Mathew
- Department of Anesthesiology, Duke University, Durham, North Carolina
| | - Jonathan P Piccini
- Cardiac Electrophysiology Section, Duke Heart Center and Department of Medicine, Duke University Medical Center, Durham, North Carolina; Duke Clinical Research Institute, Durham, North Carolina.
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30
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Thompson N, Ravagli E, Mastitskaya S, Iacoviello F, Stathopoulou TR, Perkins J, Shearing PR, Aristovich K, Holder D. Organotopic organization of the porcine mid-cervical vagus nerve. Front Neurosci 2023; 17:963503. [PMID: 37205051 PMCID: PMC10185768 DOI: 10.3389/fnins.2023.963503] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 04/04/2023] [Indexed: 05/21/2023] Open
Abstract
Introduction Despite detailed characterization of fascicular organization of somatic nerves, the functional anatomy of fascicles evident in human and large mammal cervical vagus nerve is unknown. The vagus nerve is a prime target for intervention in the field of electroceuticals due to its extensive distribution to the heart, larynx, lungs, and abdominal viscera. However, current practice of the approved vagus nerve stimulation (VNS) technique is to stimulate the entire nerve. This produces indiscriminate stimulation of non-targeted effectors and undesired side effects. Selective neuromodulation is now a possibility with a spatially-selective vagal nerve cuff. However, this requires the knowledge of the fascicular organization at the level of cuff placement to inform selectivity of only the desired target organ or function. Methods and results We imaged function over milliseconds with fast neural electrical impedance tomography and selective stimulation, and found consistent spatially separated regions within the nerve correlating with the three fascicular groups of interest, suggesting organotopy. This was independently verified with structural imaging by tracing anatomical connections from the end organ with microCT and the development of an anatomical map of the vagus nerve. This confirmed organotopic organization. Discussion Here we show, for the first time, localized fascicles in the porcine cervical vagus nerve which map to cardiac, pulmonary and recurrent laryngeal function (N = 4). These findings pave the way for improved outcomes in VNS as unwanted side effects could be reduced by targeted selective stimulation of identified organ-specific fiber-containing fascicles and the extension of this technique clinically beyond the currently approved disorders to treat heart failure, chronic inflammatory disorders, and more.
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Affiliation(s)
- Nicole Thompson
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
- *Correspondence: Nicole Thompson,
| | - Enrico Ravagli
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Svetlana Mastitskaya
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Francesco Iacoviello
- Electrochemical Innovations Lab, Department of Chemical Engineering, University College London, London, United Kingdom
| | | | - Justin Perkins
- Department of Clinical Science and Services, The Royal Veterinary College, Hatfield, United Kingdom
| | - Paul R. Shearing
- Electrochemical Innovations Lab, Department of Chemical Engineering, University College London, London, United Kingdom
| | - Kirill Aristovich
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - David Holder
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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31
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Abstract
Autonomic imbalance with a sympathetic dominance is acknowledged to be a critical determinant of the pathophysiology of chronic heart failure with reduced ejection fraction (HFrEF), regardless of the etiology. Consequently, therapeutic interventions directly targeting the cardiac autonomic nervous system, generally referred to as neuromodulation strategies, have gained increasing interest and have been intensively studied at both the pre-clinical level and the clinical level. This review will focus on device-based neuromodulation in the setting of HFrEF. It will first provide some general principles about electrical neuromodulation and discuss specifically the complex issue of dose-response with this therapeutic approach. The paper will thereafter summarize the rationale, the pre-clinical and the clinical data, as well as the future prospectives of the three most studied form of device-based neuromodulation in HFrEF. These include cervical vagal nerve stimulation (cVNS), baroreflex activation therapy (BAT), and spinal cord stimulation (SCS). BAT has been approved by the Food and Drug Administration for use in patients with HfrEF, while the other two approaches are still considered investigational; VNS is currently being investigated in a large phase III Study.
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Affiliation(s)
- Veronica Dusi
- Division of Cardiology, Cardiovascular and Thoracic Department, Città della Salute e della Scienza, University of Turin , Corso Bramante 88, 10126 Turin , Italy
| | - Filippo Angelini
- Division of Cardiology, Cardiovascular and Thoracic Department, Città della Salute e della Scienza, University of Turin , Corso Bramante 88, 10126 Turin , Italy
| | - Michael R Zile
- Division of Cardiology, Department of Medicine, Medical University of South Carolina and RHJ Department of Veteran's Affairs Medical Center , Charleston, SC , USA
| | - Gaetano Maria De Ferrari
- Division of Cardiology, Cardiovascular and Thoracic Department, Città della Salute e della Scienza, University of Turin , Corso Bramante 88, 10126 Turin , Italy
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32
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Allen E, Pongpaopattanakul P, Chauhan RA, Brack KE, Ng GA. The Effects of Vagus Nerve Stimulation on Ventricular Electrophysiology and Nitric Oxide Release in the Rabbit Heart. Front Physiol 2022; 13:867705. [PMID: 35755432 PMCID: PMC9213784 DOI: 10.3389/fphys.2022.867705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/18/2022] [Indexed: 12/03/2022] Open
Abstract
Background: Abnormal autonomic activity including impaired parasympathetic control is a known hallmark of heart failure (HF). Vagus nerve stimulation (VNS) has been shown to reduce the susceptibility of the heart to ventricular fibrillation, however the precise underlying mechanisms are not well understood and the detailed stimulation parameters needed to improve patient outcomes clinically are currently inconclusive. Objective: To investigate NO release and cardiac electrophysiological effects of electrical stimulation of the vagus nerve at varying parameters using the isolated innervated rabbit heart preparation. Methods: The right cervical vagus nerve was electrically stimulated in the innervated isolated rabbit heart preparation (n = 30). Heart rate (HR), effective refractory period (ERP), ventricular fibrillation threshold (VFT) and electrical restitution were measured as well as NO release from the left ventricle. Results: High voltage with low frequency VNS resulted in the most significant reduction in HR (by −20.6 ± 3.3%, −25.7 ± 3.0% and −30.5 ± 3.0% at 0.1, 1 and 2 ms pulse widths, with minimal increase in NO release. Low voltage and high frequency VNS significantly altered NO release in the left ventricle, whilst significantly flattening the slope of restitution and significantly increasing VFT. HR changes however using low voltage, high frequency VNS were minimal at 20Hz (to 138.5 ± 7.7 bpm (−7.3 ± 2.0%) at 1 ms pulse width and 141.1 ± 6.6 bpm (−4.4 ± 1.1%) at 2 ms pulse width). Conclusion: The protective effects of the VNS are independent of HR reductions demonstrating the likelihood of such effects being as a result of the modulation of more than one molecular pathway. Altering the parameters of VNS impacts neural fibre recruitment in the ventricle; influencing changes in ventricular electrophysiology, the protective effect of VNS against VF and the release of NO from the left ventricle.
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Affiliation(s)
- Emily Allen
- Department of Cardiovascular Sciences, Glenfield Hospital, University of Leicester, Leicester, United Kingdom.,NIHR Leicester BRC, Glenfield Hospital, Leicester, United Kingdom
| | - Pott Pongpaopattanakul
- Department of Cardiovascular Sciences, Glenfield Hospital, University of Leicester, Leicester, United Kingdom.,NIHR Leicester BRC, Glenfield Hospital, Leicester, United Kingdom
| | - Reshma A Chauhan
- Department of Cardiovascular Sciences, Glenfield Hospital, University of Leicester, Leicester, United Kingdom.,NIHR Leicester BRC, Glenfield Hospital, Leicester, United Kingdom
| | - Kieran E Brack
- Department of Cardiovascular Sciences, Glenfield Hospital, University of Leicester, Leicester, United Kingdom.,NIHR Leicester BRC, Glenfield Hospital, Leicester, United Kingdom
| | - G André Ng
- Department of Cardiovascular Sciences, Glenfield Hospital, University of Leicester, Leicester, United Kingdom.,NIHR Leicester BRC, Glenfield Hospital, Leicester, United Kingdom
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33
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Branen A, Yao Y, Kothare MV, Mahmoudi B, Kumar G. Data Driven Control of Vagus Nerve Stimulation for the Cardiovascular System: An in Silico Computational Study. Front Physiol 2022; 13:798157. [PMID: 35721533 PMCID: PMC9204199 DOI: 10.3389/fphys.2022.798157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/02/2022] [Indexed: 11/17/2022] Open
Abstract
Vagus nerve stimulation is an emerging therapy that seeks to offset pathological conditions by electrically stimulating the vagus nerve through cuff electrodes, where an electrical pulse is defined by several parameters such as pulse amplitude, pulse width, and pulse frequency. Currently, vagus nerve stimulation is under investigation for the treatment of heart failure, cardiac arrhythmia and hypertension. Through several clinical trials that sought to assess vagus nerve stimulation for the treatment of heart failure, stimulation parameters were determined heuristically and the results were inconclusive, which has led to the suggestion of using a closed-loop approach to optimize the stimulation parameters. A recent investigation has demonstrated highly specific control of cardiovascular physiology by selectively activating different fibers in the vagus nerve. When multiple locations and multiple stimulation parameters are considered for optimization, the design of closed-loop control becomes considerably more challenging. To address this challenge, we investigated a data-driven control scheme for both modeling and controlling the rat cardiovascular system. Using an existing in silico physiological model of a rat heart to generate synthetic input-output data, we trained a long short-term memory network (LSTM) to map the effect of stimulation on the heart rate and blood pressure. The trained LSTM was utilized in a model predictive control framework to optimize the vagus nerve stimulation parameters for set point tracking of the heart rate and the blood pressure in closed-loop simulations. Additionally, we altered the underlying in silico physiological model to consider intra-patient variability, and diseased dynamics from increased sympathetic tone in designing closed-loop VNS strategies. Throughout the different simulation scenarios, we leveraged the design of the controller to demonstrate alternative clinical objectives. Our results show that the controller can optimize stimulation parameters to achieve set-point tracking with nominal offset while remaining computationally efficient. Furthermore, we show a controller formulation that compensates for mismatch due to intra-patient variabilty, and diseased dynamics. This study demonstrates the first application and a proof-of-concept for using a purely data-driven approach for the optimization of vagus nerve stimulation parameters in closed-loop control of the cardiovascular system.
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Affiliation(s)
- Andrew Branen
- Department of Chemical and Materials Engineering, San José State University, San José, CA, United States
| | - Yuyu Yao
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, United States
| | - Mayuresh V. Kothare
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, United States
| | - Babak Mahmoudi
- Department of Biomedical Informatics and Biomedical Engineering, School of Medicine, Emory University, Atlanta, GA, United States
| | - Gautam Kumar
- Department of Chemical and Materials Engineering, San José State University, San José, CA, United States
- *Correspondence: Gautam Kumar,
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Ahmed U, Chang YC, Zafeiropoulos S, Nassrallah Z, Miller L, Zanos S. Strategies for precision vagus neuromodulation. Bioelectron Med 2022; 8:9. [PMID: 35637543 PMCID: PMC9150383 DOI: 10.1186/s42234-022-00091-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/05/2022] [Indexed: 12/21/2022] Open
Abstract
The vagus nerve is involved in the autonomic regulation of physiological homeostasis, through vast innervation of cervical, thoracic and abdominal visceral organs. Stimulation of the vagus with bioelectronic devices represents a therapeutic opportunity for several disorders implicating the autonomic nervous system and affecting different organs. During clinical translation, vagus stimulation therapies may benefit from a precision medicine approach, in which stimulation accommodates individual variability due to nerve anatomy, nerve-electrode interface or disease state and aims at eliciting therapeutic effects in targeted organs, while minimally affecting non-targeted organs. In this review, we discuss the anatomical and physiological basis for precision neuromodulation of the vagus at the level of nerve fibers, fascicles, branches and innervated organs. We then discuss different strategies for precision vagus neuromodulation, including fascicle- or fiber-selective cervical vagus nerve stimulation, stimulation of vagal branches near the end-organs, and ultrasound stimulation of vagus terminals at the end-organs themselves. Finally, we summarize targets for vagus neuromodulation in neurological, cardiovascular and gastrointestinal disorders and suggest potential precision neuromodulation strategies that could form the basis for effective and safe therapies.
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Affiliation(s)
- Umair Ahmed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York, USA
| | - Yao-Chuan Chang
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York, USA
| | - Stefanos Zafeiropoulos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York, USA
| | - Zeinab Nassrallah
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Larry Miller
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York, USA
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York, USA.
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA.
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35
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Habibagahi I, Omidbeigi M, Hadaya J, Lyu H, Jang J, Ardell JL, Bari AA, Babakhani A. Vagus nerve stimulation using a miniaturized wirelessly powered stimulator in pigs. Sci Rep 2022; 12:8184. [PMID: 35581302 PMCID: PMC9114380 DOI: 10.1038/s41598-022-11850-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/26/2022] [Indexed: 11/09/2022] Open
Abstract
Neuromodulation of peripheral nerves has been clinically used for a wide range of indications. Wireless and batteryless stimulators offer important capabilities such as no need for reoperation, and extended life compared to their wired counterparts. However, there are challenging trade-offs between the device size and its operating range, which can limit their use. This study aimed to examine the functionality of newly designed wirelessly powered and controlled implants in vagus nerve stimulation for pigs. The implant used near field inductive coupling at 13.56 MHz industrial, scientific, and medical band to harvest power from an external coil. The circular implant had a diameter of 13 mm and weighed 483 mg with cuff electrodes. The efficiency of the inductive link and robustness to distance and misalignment were optimized. As a result, the specific absorption rate was orders of magnitude lower than the safety limit, and the stimulation can be performed using only 0.1 W of external power. For the first time, wireless and batteryless VNS with more than 5 cm operation range was demonstrated in pigs. A total of 84 vagus nerve stimulations (10 s each) have been performed in three adult pigs. In a quantitative comparison of the effectiveness of VNS devices, the efficiency of systems on reducing heart rate was similar in both conventional (75%) and wireless (78.5%) systems. The pulse width and frequency of the stimulation were swept on both systems, and the response for physiological markers was drawn. The results were easily reproducible, and methods used in this study can serve as a basis for future wirelessly powered implants.
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Affiliation(s)
- Iman Habibagahi
- Electrical and Computer Engineering Department, University of California Los Angeles, Los Angeles, CA, USA.
| | - Mahmoud Omidbeigi
- Department of Neurosurgery, University of California at Los Angeles, Los Angeles, CA, USA.
| | - Joseph Hadaya
- UCLA Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, CA, USA.,UCLA Neurocardiology Research Program of Excellence, University of California Los Angeles, Los Angeles, CA, USA.,Molecular, Cellular and Integrative Physiology Program, University of California Los Angeles, Los Angeles, CA, USA
| | - Hongming Lyu
- Electrical and Computer Engineering Department, University of California Los Angeles, Los Angeles, CA, USA
| | - Jaeeun Jang
- Electrical and Computer Engineering Department, University of California Los Angeles, Los Angeles, CA, USA
| | - Jeffrey L Ardell
- UCLA Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, CA, USA.,UCLA Neurocardiology Research Program of Excellence, University of California Los Angeles, Los Angeles, CA, USA
| | - Ausaf A Bari
- Department of Neurosurgery, University of California at Los Angeles, Los Angeles, CA, USA
| | - Aydin Babakhani
- Electrical and Computer Engineering Department, University of California Los Angeles, Los Angeles, CA, USA.
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36
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Konstam MA, Mann DL, Udelson JJE, Ardell JL, De Ferrari GM, Cowie MR, Klein HU, Gregory DD, Massaro JM, Libbus I, DiCarlo LA, Butler J, Parker JD, Teerlink JR. Advances in Our Clinical Understanding of Autonomic Regulation Therapy Using Vagal Nerve Stimulation in Patients Living With Heart Failure. Front Physiol 2022; 13:857538. [PMID: 35530511 PMCID: PMC9068946 DOI: 10.3389/fphys.2022.857538] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/21/2022] [Indexed: 11/17/2022] Open
Abstract
The ANTHEM-HF, INOVATE-HF, and NECTAR-HF clinical studies of autonomic regulation therapy (ART) using vagus nerve stimulation (VNS) systems have collectively provided dose-ranging information enabling the development of several working hypotheses on how stimulation frequency can be utilized during VNS for tolerability and improving cardiovascular outcomes in patients living with heart failure (HF) and reduced ejection fraction (HFrEF). Changes in heart rate dynamics, comprising reduced heart rate (HR) and increased HR variability, are a biomarker of autonomic nerve system engagement and cardiac control, and appear to be sensitive to VNS that is delivered using a stimulation frequency that is similar to the natural operating frequency of the vagus nerve. Among prior studies, the ANTHEM-HF Pilot Study has provided the clearest evidence of autonomic engagement with VNS that was delivered using a stimulation frequency that was within the operating range of the vagus nerve. Achieving autonomic engagement was accompanied by improvement from baseline in six-minute walk duration (6MWD), health-related quality of life, and left ventricular EF (LVEF), over and above those achieved by concomitant guideline-directed medical therapy (GDMT) administered to counteract harmful neurohormonal activation, with relative freedom from deleterious effects. Autonomic engagement and positive directional changes have persisted over time, and an exploratory analysis suggests that improvement in autonomic tone, symptoms, and physical capacity may be independent of baseline NT-proBNP values. Based upon these encouraging observations, prospective, randomized controlled trials examining the effects on symptoms and cardiac function as well as natural history have been warranted. A multi-national, large-scale, randomized, controlled trial is well underway to determine the outcomes associated with ART using autonomic nervous system engagement as a guide for VNS delivery.
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Affiliation(s)
- Marvin A Konstam
- The CardioVascular Center at Tufts Medical Center, Boston, MA, United States
| | - Douglas L Mann
- Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, United States
| | | | - Jeffrey L Ardell
- UCLA Neurocardiology Program of Excellence, University of California, Los Angeles, Los Angeles, CA, United States
| | | | - Martin R Cowie
- School of Cardiovascular Medicine and Sciences, King's College London, London, United Kingdom
| | - Helmut U Klein
- Division of Cardiology, University of Rochester Medical Center, Rochester, NY, United States
| | - Douglas D Gregory
- Clinical Cardiovascular Science Foundation, Boston, MA, United States
| | - Joseph M Massaro
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA, United States
| | - Imad Libbus
- LivaNova USA Incorporated, Houston, TX, United States
| | | | - Javed Butler
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS, United States
| | - John D Parker
- University of Toronto, University Health Network, Toronto, ON, Canada
| | - John R Teerlink
- Section of Cardiology, San Francisco Veterans Affairs Medical Center and School of Medicine, University of California, San Francisco, San Francisco, CA, United States
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37
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Ottaviani MM, Vallone F, Micera S, Recchia FA. Closed-Loop Vagus Nerve Stimulation for the Treatment of Cardiovascular Diseases: State of the Art and Future Directions. Front Cardiovasc Med 2022; 9:866957. [PMID: 35463766 PMCID: PMC9021417 DOI: 10.3389/fcvm.2022.866957] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/14/2022] [Indexed: 01/07/2023] Open
Abstract
The autonomic nervous system exerts a fine beat-to-beat regulation of cardiovascular functions and is consequently involved in the onset and progression of many cardiovascular diseases (CVDs). Selective neuromodulation of the brain-heart axis with advanced neurotechnologies is an emerging approach to corroborate CVDs treatment when classical pharmacological agents show limited effectiveness. The vagus nerve is a major component of the cardiac neuroaxis, and vagus nerve stimulation (VNS) is a promising application to restore autonomic function under various pathological conditions. VNS has led to encouraging results in animal models of CVDs, but its translation to clinical practice has not been equally successful, calling for more investigation to optimize this technique. Herein we reviewed the state of the art of VNS for CVDs and discuss avenues for therapeutic optimization. Firstly, we provided a succinct description of cardiac vagal innervation anatomy and physiology and principles of VNS. Then, we examined the main clinical applications of VNS in CVDs and the related open challenges. Finally, we presented preclinical studies that aim at overcoming VNS limitations through optimization of anatomical targets, development of novel neural interface technologies, and design of efficient VNS closed-loop protocols.
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Affiliation(s)
- Matteo Maria Ottaviani
- Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa, Italy
- Department of Excellence in Robotics and Artificial Intelligence, The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy
| | - Fabio Vallone
- Department of Excellence in Robotics and Artificial Intelligence, The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy
| | - Silvestro Micera
- Department of Excellence in Robotics and Artificial Intelligence, The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy
- Bertarelli Foundation Chair in Translational Neural Engineering, Center for Neuroprosthetics, Institute of Bioengineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Fabio A. Recchia
- Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana Gabriele Monasterio, Pisa, Italy
- Department of Physiology, Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
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38
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Hoang JD, Yamakawa K, Rajendran PS, Chan CA, Yagishita D, Nakamura K, Lux RL, Vaseghi M. Proarrhythmic Effects of Sympathetic Activation Are Mitigated by Vagal Nerve Stimulation in Infarcted Hearts. JACC Clin Electrophysiol 2022; 8:513-525. [PMID: 35450607 PMCID: PMC9034056 DOI: 10.1016/j.jacep.2022.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/11/2022] [Accepted: 01/11/2022] [Indexed: 10/18/2022]
Abstract
OBJECTIVES The goal of this study was to evaluate whether intermittent VNS reduces electrical heterogeneities and arrhythmia inducibility during sympathoexcitation. BACKGROUND Sympathoexcitation increases the risk of ventricular tachyarrhythmias (VT). Vagal nerve stimulation (VNS) has been antiarrhythmic in the setting of ischemia-driven arrhythmias, but it is unclear if it can overcome the electrophysiological effects of sympathoexcitation in the setting of chronic myocardial infarction (MI). METHODS In Yorkshire pigs after chronic MI, a sternotomy was performed, a 56-electrode sock was placed over the ventricles (n = 17), and a basket catheter was positioned in the left ventricle (n = 6). Continuous unipolar electrograms from sock and basket arrays were obtained to analyze activation recovery interval (ARI), a surrogate of action potential duration. Bipolar voltage mapping was performed to define scar, border zone, or viable myocardium. Hemodynamic and electrical parameters and VT inducibility were evaluated during sympathoexcitation with bilateral stellate ganglia stimulation (BSS) and during combined BSS with intermittent VNS. RESULTS During BSS, global epicardial ARIs shortened from 384 ± 59 milliseconds to 297 ± 63 milliseconds and endocardial ARIs from 359 ± 36 milliseconds to 318 ± 40 milliseconds. Dispersion in ARIs increased in all regions, with the greatest increase observed in scar and border zone regions. VNS mitigated the effects of BSS on border zone ARIs (from -18.3% ± 6.3% to -2.1% ± 14.7%) and ARI dispersion (from 104 ms2 [1 to 1,108 ms2] to -108 ms2 [IQR: -588 to 30 ms2]). VNS reduced VT inducibility during sympathoexcitation (from 75%-40%; P < 0.05). CONCLUSIONS After chronic MI, VNS overcomes the detrimental effects of sympathoexcitation by reducing electrophysiological heterogeneities exacerbated by sympathetic stimulation, decreasing VT inducibility.
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Affiliation(s)
- Jonathan D Hoang
- UCLA Cardiac Arrhythmia Center, University of California, Los Angeles, California, USA; UCLA Neurocardiology Program of Excellence, University of California, Los Angeles, California, USA; Molecular, Cellular and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, California, USA
| | - Kentaro Yamakawa
- UCLA Cardiac Arrhythmia Center, University of California, Los Angeles, California, USA
| | - Pradeep S Rajendran
- UCLA Cardiac Arrhythmia Center, University of California, Los Angeles, California, USA; UCLA Neurocardiology Program of Excellence, University of California, Los Angeles, California, USA
| | - Christopher A Chan
- UCLA Cardiac Arrhythmia Center, University of California, Los Angeles, California, USA; UCLA Neurocardiology Program of Excellence, University of California, Los Angeles, California, USA
| | - Daigo Yagishita
- UCLA Cardiac Arrhythmia Center, University of California, Los Angeles, California, USA
| | - Keijiro Nakamura
- UCLA Cardiac Arrhythmia Center, University of California, Los Angeles, California, USA
| | - Robert L Lux
- UCLA Cardiac Arrhythmia Center, University of California, Los Angeles, California, USA
| | - Marmar Vaseghi
- UCLA Cardiac Arrhythmia Center, University of California, Los Angeles, California, USA; UCLA Neurocardiology Program of Excellence, University of California, Los Angeles, California, USA; Molecular, Cellular and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, California, USA.
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Verrier RL, Libbus I, Nearing BD, KenKnight BH. Multifactorial Benefits of Chronic Vagus Nerve Stimulation on Autonomic Function and Cardiac Electrical Stability in Heart Failure Patients With Reduced Ejection Fraction. Front Physiol 2022; 13:855756. [PMID: 35431984 PMCID: PMC9005779 DOI: 10.3389/fphys.2022.855756] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 02/21/2022] [Indexed: 12/20/2022] Open
Abstract
Heart failure with reduced left ventricular ejection fraction is a progressive disease that claims > 352,000 lives annually in the United States alone. Despite the development of an extensive array of pharmacologic and device therapies, prognosis remains poor. Disruption in autonomic balance in the form of heightened sympathetic nerve activity and reduced vagal tone have been established as major causes of heart failure progression. Interest in chronic neuromodulation mediated by vagus nerve stimulation (VNS) has intensified in recent years. This review focuses on four main goals: (1) To review the preclinical evidence that supports the concept of a cardioprotective effect of VNS on autonomic function and cardiac electrical stability along with the underlying putative mechanisms. (2) To present the initial clinical experience with chronic VNS in patients with heart failure and highlight the controversial aspects of the findings. (3) To discuss the latest findings of the multifactorial effects of VNS on autonomic tone, baroreceptor sensitivity, and cardiac electrical stability and the state-of-the-art methods employed to monitor these relationships. (4) To discuss the implications of the current findings and the gaps in knowledge that require attention in future investigations.
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Affiliation(s)
- Richard L. Verrier
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Harvard Medical School, Boston, MA, United States
- *Correspondence: Richard L. Verrier, , orcid.org/0000-0001-5602-6793
| | - Imad Libbus
- LivaNova USA, Inc., Houston, TX, United States
| | - Bruce D. Nearing
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Harvard Medical School, Boston, MA, United States
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Libbus I, Premchand RK, Sharma K, Mittal S, Monteiro R, Amurthur B, KenKnight BH, DiCarlo LA, Anand IS. Persistent Autonomic Engagement and Cardiac Control After Four or More Years of Autonomic Regulation Therapy Using Vagus Nerve Stimulation. Front Physiol 2022; 13:853617. [PMID: 35360224 PMCID: PMC8963780 DOI: 10.3389/fphys.2022.853617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 02/16/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Although heart failure (HF) outcomes have improved dramatically with the use of guideline directed medical therapy and implantable devices, the overall prognosis of patients with HF and reduced ejection fraction (HFrEF) remains poor. Autonomic Regulation Therapy (ART) using chronic vagus nerve stimulation (VNS) has been evaluated in the ANTHEM-HF study, using changes in heart rate (HR) dynamics as a biomarker of autonomic nervous system engagement and cardiac control to guide VNS titration. ART was associated with sustained improvement in cardiac function and HF symptoms in patients with HFrEF and persistent HF symptoms despite guideline-directed medical therapy (GDMT). We sought to determine whether the responsiveness of the autonomic nervous system to ART, as reflected in HR response to vagus stimulation during the VNS duty cycle, is maintained after long-term chronic VNS administration. Methods Fifteen patients with HFrEF and implanted with a VNS systems in the ANTHEM-HF study were evaluated after 4.7 ± 0.3 years (range: 4.0-5.0 years) of chronic ART. ECG electrodes were placed on each patient's wrists, and ECG rhythm strips were recorded. Instantaneous HR time series was computed at each patient's chronically programmed VNS intensity and during progressively increasing VNS intensity. HR during active stimulation (on-time) was compared to HR just prior to initiation of each stimulation cycle (off-time). Results Persistent autonomic engagement was observed in a majority of patients (11 of 15, 73%) after chronic ART for four or more years. The average magnitude of HR reduction during ART on-time in all patients was 2.4 ± 3.2 bpm at the chronically programmed VNS pulse parameter settings. Conclusion Autonomic responsiveness to VNS persists in patients with HFrEF who received chronic ART for up to 5 years as a supplement to GDMT. This suggests that the effects of ART on autonomic engagement and cardiac control remain durable over time. Clinical Trial Registration [ClinicalTrials.gov], identifier [#NCT01823887, CTRI registration #CTRI/2012/05/002681].
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Affiliation(s)
- Imad Libbus
- LivaNova USA, Inc., Houston, TX, United States
| | | | - Kamal Sharma
- Sanjivani Super Specialty Hospitals, Ahmedabad, India
| | | | | | | | | | | | - Inder S. Anand
- Emeritus, University of Minnesota, Minneapolis, MN, United States
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Structural and function organization of intrathoracic extracardiac autonomic projections to the porcine heart: implications for targeted neuromodulation therapy. Heart Rhythm 2022; 19:975-983. [DOI: 10.1016/j.hrthm.2022.01.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/20/2022] [Accepted: 01/28/2022] [Indexed: 12/30/2022]
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42
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Stress-related dysautonomias and neurocardiology-based treatment approaches. Auton Neurosci 2022; 239:102944. [DOI: 10.1016/j.autneu.2022.102944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 10/13/2021] [Accepted: 01/16/2022] [Indexed: 11/21/2022]
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43
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Abstract
Vagal nerve stimulation (VNS) has a strong pathophysiological rationale as a potentially beneficial treatment for heart failure with reduced ejection fraction. Despite several promising preclinical studies and pilot clinical studies, the two large, controlled trials—NECTAR-HF and INOVATE-HF—failed to demonstrate the expected benefit. It is likely that clinical application of VNS in phase III studies was performed before a sufficient degree of understanding of the complex pathophysiology of autonomic electrical modulation had been achieved, therefore leading to an underestimation of its potential benefit. More knowledge on the complex dose–response issue of VNS (i.e., pulse amplitude, frequency, duration and duty cycle) has been gathered since these trials and a new randomized study is currently underway with an adaptive design and a refined approach in an attempt to deliver the proper dose to a more selected group of patients.
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Affiliation(s)
- Veronica Dusi
- Division of Cardiology, Department of Medical Sciences, Citta della Salute e della Scienza Hospital, University of Turin, Corso Bramante 88, 10126, Turin, Italy.
| | - Gaetano Maria De Ferrari
- Division of Cardiology, Department of Medical Sciences, Citta della Salute e della Scienza Hospital, University of Turin, Corso Bramante 88, 10126, Turin, Italy
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Carandina A, Rodrigues GD, Di Francesco P, Filtz A, Bellocchi C, Furlan L, Carugo S, Montano N, Tobaldini E. Effects of transcutaneous auricular vagus nerve stimulation on cardiovascular autonomic control in health and disease. Auton Neurosci 2021; 236:102893. [PMID: 34649119 DOI: 10.1016/j.autneu.2021.102893] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/24/2021] [Accepted: 10/04/2021] [Indexed: 01/01/2023]
Abstract
Autonomic nervous system (ANS) dysfunction is a well-known feature of cardiovascular diseases (CVDs). Studies on heart rate variability (HRV), a non-invasive method useful in investigating the status of cardiovascular autonomic control, have shown that a predominance of sympathetic modulation not only contributes to the progression of CVDs but has a pivotal role in their onset. Current therapies focus more on inhibition of sympathetic activity, but the presence of drug-resistant conditions and the invasiveness of some surgical procedures are an obstacle to complete therapeutic success. On the other hand, targeting the parasympathetic branch of the autonomic nervous system through invasive vagus nerve stimulation (VNS) has shown interesting results as alternative therapeutic approach for CVDs. However, the invasiveness and cost of the surgical procedure limit the clinical applicability of VNS and hinder the research on the physiological pathway involved. Transcutaneous stimulation of the auricular branch of the vagus nerve (tVNS) seems to represent an important non-invasive alternative with effects comparable to those of VNS with surgical implant. Thus, in the present narrative review, we illustrate the main studies on tVNS performed in healthy subjects and in three key examples of CVDs, namely heart failure, hypertension and atrial fibrillation, highlighting the neuromodulatory effects of this technique.
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Affiliation(s)
- Angelica Carandina
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Gabriel Dias Rodrigues
- Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Brazil; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Pietro Di Francesco
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Annalisa Filtz
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Chiara Bellocchi
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Ludovico Furlan
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Stefano Carugo
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Nicola Montano
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.
| | - Eleonora Tobaldini
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
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Hsieh CM, Lin WC, Peng HY, Chen HC, Ho YC, Li CJ, Wu XG, Chung JY, Lee SD, Lin TB. Shoulder transcutaneous electric nerve stimulation decreases heart rate via potentiating vagal tone. Sci Rep 2021; 11:19168. [PMID: 34580404 PMCID: PMC8476641 DOI: 10.1038/s41598-021-98690-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 09/07/2021] [Indexed: 11/23/2022] Open
Abstract
By enhancing vagal activity, auricle transcutaneous electric nerve stimulation (TENS) is developed as a non-invasive therapy for heart failure. Nevertheless, though shoulder TENS used for treating adhesive capsulitis could affect vagal tone, its potential impact on heart functions remains unclear. In this study, electrocardiogram (ECG) and heart rate (HR) of subjects in response to sham, right-sided, or left-sided shoulder TENS (TENS-S, TENS-R, and TENS-L, respectively; 5 min) were recorded and analyzed. During the stimulation period, TENS-R constantly and TENS-L transiently decreased the HR of subjects; both TENS-R and TENS-L increased powers of the low- and high-frequency spectra. While TENS-R exhibiting no effect, TENS-L increased the ratio of low/high-frequency power spectrum indicating TENS-R decreased the HR through potentiating cardiac vagal tone. Collectively, these results suggest TENS could be an early and non-invasive therapy for heart failure patients before considering implant devices or devices are not feasible; moreover, therapists/physicians need to carefully monitor the potential adverse events during treatment for patient safety. Trial registration: The study protocol was registered in ClinicalTrials.gov (NCT03982472; 11/06/2019).
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Affiliation(s)
- Chun-Ming Hsieh
- Division of Physical Therapy, St. Paul's Hospital, Taoyuan, Taiwan
| | - Wan-Chen Lin
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, No. 250, Wu-Hsing Street, Taipei, 11031, Taiwan.,National Taiwan University Hospital, Taipei, Taiwan
| | - Hsien-Yu Peng
- Department of Medicine, Mackay Medical College, New Taipei, Taiwan
| | - Huang-Chung Chen
- Department of Rehabilitation, St. Paul's Hospital, Taoyuan, Taiwan
| | - Yu-Cheng Ho
- Department of Medicine, Mackay Medical College, New Taipei, Taiwan
| | - Chi-Jui Li
- Division of Physical Therapy, St. Paul's Hospital, Taoyuan, Taiwan
| | - Xi-Guan Wu
- Division of Physical Therapy, St. Paul's Hospital, Taoyuan, Taiwan
| | - Jen-Yi Chung
- Division of Physical Therapy, St. Paul's Hospital, Taoyuan, Taiwan
| | - Shin-Da Lee
- Department of Occupational Therapy, Asia University, Taichung, Taiwan.,Department of Physical Therapy, Graduate Institute of Rehabilitation Science, China Medical University, Taichung, Taiwan.,School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Tzer-Bin Lin
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, No. 250, Wu-Hsing Street, Taipei, 11031, Taiwan. .,Department of Bioinformatics and Medical Engineering, Asia University, Taichung, Taiwan. .,Department of Biotechnology, Asia University, Taichung, Taiwan. .,Cell Physiology and Molecular Image Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
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Stavrakis S, Kulkarni K, Singh JP, Katritsis DG, Armoundas AA. Autonomic Modulation of Cardiac Arrhythmias: Methods to Assess Treatment and Outcomes. JACC Clin Electrophysiol 2021; 6:467-483. [PMID: 32439031 DOI: 10.1016/j.jacep.2020.02.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/06/2020] [Accepted: 02/14/2020] [Indexed: 02/08/2023]
Abstract
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.
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Affiliation(s)
- Stavros Stavrakis
- Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
| | - Kanchan Kulkarni
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, Massachusetts, USA
| | | | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
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Kulkarni K, Stavrakis S, Elkholey K, Singh JP, Parks KA, Armoundas AA. Microvolt T-Wave Alternans Is Modulated by Acute Low-Level Tragus Stimulation in Patients With Ischemic Cardiomyopathy and Heart Failure. Front Physiol 2021; 12:707724. [PMID: 34366894 PMCID: PMC8343129 DOI: 10.3389/fphys.2021.707724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/30/2021] [Indexed: 12/15/2022] Open
Abstract
Aims: Microvolt T-wave alternans (TWA), an oscillation in T-wave morphology of the electrocardiogram (ECG), has been associated with increased susceptibility to ventricular tachy-arrhythmias, while vagus nerve stimulation has shown promising anti-arrhythmic effects in in vivo and ex vivo animal studies. We aimed to examine the effect of non-invasive, acute low-level tragus stimulation (LLTS) on TWA in patients with ischemic cardiomyopathy and heart failure. Methods: 26 patients with ischemic cardiomyopathy (left ventricular ejection fraction <35%) and chronic stable heart failure, previously implanted with an automatic implantable cardioverter defibrillator (ICD) device with an atrial lead (dual chamber ICD or cardiac resynchronization therapy defibrillator), were enrolled in the study. Each patient sequentially received, (1) Sham LLTS (electrode on tragus, but no stimulation delivered) for 5 min; (2) Active LLTS at two different frequencies (5 and 20 Hz, 15 min each); and (3) Active LLTS, during concomitant atrial pacing at 100 bpm at two different frequencies (5 and 20 Hz, 15 min each). LLTS was delivered through a transcutaneous electrical nerve stimulation device (pulse width 200 μs, frequency 5/20 Hz, amplitude 1 mA lower than the discomfort threshold). TWA burden was assessed using continuous ECG monitoring during sham and active LLTS in sinus rhythm, as well as during atrial pacing. Results: Right atrial pacing at 100 bpm led to significantly heightened TWA burden compared to sinus rhythm, with or without LLTS. Acute LLTS at both 5 and 20 Hz, during sinus rhythm led to a significant rise in TWA burden in the precordial leads (p < 0.05). Conclusion: Acute LLTS results in a heart-rate dependent increase in TWA burden.
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Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, United States
| | - Stavros Stavrakis
- Heart Rhythm Institute, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Khaled Elkholey
- Heart Rhythm Institute, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA, United States
| | - Kimberly A Parks
- Cardiology Division, Brigham and Women's Hospital, Boston, MA, United States
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
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Sinkovec M, Trobec R, Meglic B. Cardiovascular responses to low-level transcutaneous vagus nerve stimulation. Auton Neurosci 2021; 236:102851. [PMID: 34274638 DOI: 10.1016/j.autneu.2021.102851] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/25/2021] [Accepted: 07/06/2021] [Indexed: 11/17/2022]
Abstract
AIMS The aim was to determine cardiovascular responses to an arbitrary protocol of transcutaneous low-level vagus nerve electrical stimulation (tVNS). METHODS Study was performed in 15 male volunteers, mean age 23 years. Data were collected during two sessions - sham stimulation (no stimulation) and stimulation. Each session included one-hour resting phase followed by 15-min autonomic nervous system testing phase (Valsalva, deep breathing, wet-cold face tests), all in supine position. The right tragus stimulation parameters were: 20 Hz, constant current at sensation threshold, 1 ms rectangular pulse width. The ECG, noninvasive arterial blood pressure and thoracic impedance cardiography measurements were recorded and analyzed continuously with the Task Force® Monitor (CNSystems Medizintechnik GmbH, Graz, Ver. 2.2.10.0). t-Test for paired samples, paired Wilcoxon signed-rank, and one-way ANOVA for repeated measurements were carried out. P < 0.05 was considered significant. RESULTS We demonstrated significant reductions of left ventricular contractility and output parameters, a trend for heart rate reduction, and resulting beneficial reduction of left ventricular work load. However, significant increases of blood pressure and total peripheral resistance were recognized, possibly as a reflex response. CONCLUSION It seems that our tVNS protocol has a potential for cardiac autonomic modulation. This gives us opportunity to advance our stimulation parameters with participant-specific adjustments. Further studies are however needed to prove the therapeutic potential of such approach in different patient groups.
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Affiliation(s)
- Matjaz Sinkovec
- Department of Cardiology, University Medical Center Ljubljana, Zaloška c. 7, 1000 Ljubljana, Slovenia.
| | - Roman Trobec
- Department of Communication Systems, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
| | - Bernard Meglic
- Department of Neurology, University Medical Center Ljubljana, Zaloška c. 7, 1000 Ljubljana, Slovenia.
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Hanna P, Buch E, Stavrakis S, Meyer C, Tompkins JD, Ardell JL, Shivkumar K. Neuroscientific therapies for atrial fibrillation. Cardiovasc Res 2021; 117:1732-1745. [PMID: 33989382 PMCID: PMC8208752 DOI: 10.1093/cvr/cvab172] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/13/2021] [Indexed: 02/06/2023] Open
Abstract
The cardiac autonomic nervous system (ANS) plays an integral role in normal cardiac physiology as well as in disease states that cause cardiac arrhythmias. The cardiac ANS, comprised of a complex neural hierarchy in a nested series of interacting feedback loops, regulates atrial electrophysiology and is itself susceptible to remodelling by atrial rhythm. In light of the challenges of treating atrial fibrillation (AF) with conventional pharmacologic and myoablative techniques, increasingly interest has begun to focus on targeting the cardiac neuraxis for AF. Strong evidence from animal models and clinical patients demonstrates that parasympathetic and sympathetic activity within this neuraxis may trigger AF, and the ANS may either induce atrial remodelling or undergo remodelling itself to serve as a substrate for AF. Multiple nexus points within the cardiac neuraxis are therapeutic targets, and neuroablative and neuromodulatory therapies for AF include ganglionated plexus ablation, epicardial botulinum toxin injection, vagal nerve (tragus) stimulation, renal denervation, stellate ganglion block/resection, baroreceptor activation therapy, and spinal cord stimulation. Pre-clinical and clinical studies on these modalities have had promising results and are reviewed here.
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Affiliation(s)
- Peter Hanna
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
- Neurocardiology Research Program of Excellence, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
- Molecular, Cellular & Integrative Physiology Program, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
| | - Eric Buch
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
| | - Stavros Stavrakis
- Heart Rhythm Institute, University of Oklahoma Health Sciences Center, 1100 N Lindsay Ave, Oklahoma City, OK 73104, USA
| | - Christian Meyer
- Division of Cardiology, cardiac Neuro- and Electrophysiology Research Consortium (cNEP), EVK Düsseldorf, Teaching Hospital University of Düsseldorf, Kirchfeldstraße 40, 40217 Düsseldorf, Germany
- Institute of Neural and Sensory Physiology, cardiac Neuro- and Electrophysiology Research Consortium (cNEP), University of Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - John D Tompkins
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
- Neurocardiology Research Program of Excellence, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
| | - Jeffrey L Ardell
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
- Neurocardiology Research Program of Excellence, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
- Molecular, Cellular & Integrative Physiology Program, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
| | - Kalyanam Shivkumar
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
- Neurocardiology Research Program of Excellence, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
- Molecular, Cellular & Integrative Physiology Program, David Geffen School of Medicine, UCLA, 100 Medical Plaza, Suite 660, Los Angeles, CA 90095, USA
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Ahmed U, Chang YC, Lopez MF, Wong J, Datta-Chaudhuri T, Rieth L, Al-Abed Y, Zanos S. Implant- and anesthesia-related factors affecting cardiopulmonary threshold intensities for vagus nerve stimulation. J Neural Eng 2021; 18. [PMID: 34036940 DOI: 10.1088/1741-2552/ac048a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 05/24/2021] [Indexed: 11/11/2022]
Abstract
Objective.Vagus nerve stimulation (VNS) is typically delivered at increasing stimulus intensity until a neurological or physiological response is observed ('threshold') for dose calibration, preclinically and therapeutically. Factors affecting VNS thresholds have not been studied systematically. In a rodent model of VNS we measured neural and physiological responses to increasing VNS intensity, determined neurological and physiological thresholds and examined the effect of implant- and anesthesia-related factors on thresholds.Approach.In acute and chronic vagus implants (45 and 20 rats, respectively) VNS was delivered under isoflurane, ketamine-xylazine, or awake conditions. Evoked compound action potentials (CAPs) were recorded and activation of different fiber types was extracted. Elicited physiological responses were registered, including changes in heart rate (HR), breathing rate (BR), and blood pressure (BP). CAP and physiological thresholds were determined.Main results. The threshold for evoking discernable CAPs (>10µV) (CAP threshold) is significantly lower than what elicits 5%-10% drop in heart rate (heart rate threshold, HRT) (25µA ± 1.8 vs. 80µA ± 5.1, respectively; mean ± SEM). Changes in BP and small changes in BR (bradypnea) occur at lowest intensities (70µA ± 8.3), followed by HR changes (80µA ± 5.1) and finally significant changes in BR (apnea) (310μA ± 32.5). HRT and electrode impedance are correlated in chronic (Pearson correlationr= 0.47;p< 0.001) but not in acute implants (r= -0.34;pNS); HRT and impedance both increase with implant age (r= 0.44;p< 0.001 andr= 0.64;p< 0.001, respectively). HRT is lowest when animals are awake (200µA ± 35.5), followed by ketamine-xylazine (640µA ± 151.5), and isoflurane (1000µA ± 139.5). The sequence of physiological responses with increasing VNS intensity is the same in anesthetized and awake animals. Pulsing frequency affects physiological responses but not CAPs.Significance. Implant age, electrode impedance, and type of anesthesia affect VNS thresholds and should be accounted for when calibrating stimulation dose.
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Affiliation(s)
- Umair Ahmed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Yao-Chuan Chang
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Maria F Lopez
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Jason Wong
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Timir Datta-Chaudhuri
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Loren Rieth
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Yousef Al-Abed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
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