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Herring N, Ajijola OA, Foreman RD, Gourine AV, Green AL, Osborn J, Paterson DJ, Paton JFR, Ripplinger CM, Smith C, Vrabec TL, Wang HJ, Zucker IH, Ardell JL. Neurocardiology: translational advancements and potential. J Physiol 2024. [PMID: 39340173 DOI: 10.1113/jp284740] [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: 03/06/2024] [Accepted: 09/03/2024] [Indexed: 09/30/2024] Open
Abstract
In our original white paper published in the The Journal of Physiology in 2016, we set out our knowledge of the structural and functional organization of cardiac autonomic control, how it remodels during disease, and approaches to exploit such knowledge for autonomic regulation therapy. The aim of this update is to build on this original blueprint, highlighting the significant progress which has been made in the field since and major challenges and opportunities that exist with regard to translation. Imbalances in autonomic responses, while beneficial in the short term, ultimately contribute to the evolution of cardiac pathology. As our understanding emerges of where and how to target in terms of actuators (including the heart and intracardiac nervous system (ICNS), stellate ganglia, dorsal root ganglia (DRG), vagus nerve, brainstem, and even higher centres), there is also a need to develop sensor technology to respond to appropriate biomarkers (electrophysiological, mechanical, and molecular) such that closed-loop autonomic regulation therapies can evolve. The goal is to work with endogenous control systems, rather than in opposition to them, to improve outcomes.
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Affiliation(s)
- N Herring
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - O A Ajijola
- UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - R D Foreman
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - A V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, University College London, London, UK
| | - A L Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - J Osborn
- Department of Surgery, University of Minnesota, Minneapolis, MN, USA
| | - D J Paterson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - J F R Paton
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - C M Ripplinger
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - C Smith
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - T L Vrabec
- Department of Physical Medicine and Rehabilitation, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - H J Wang
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - I H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - J L Ardell
- UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
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2
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Donahue JK, Chrispin J, Ajijola OA. Mechanism of Ventricular Tachycardia Occurring in Chronic Myocardial Infarction Scar. Circ Res 2024; 134:328-342. [PMID: 38300981 PMCID: PMC10836816 DOI: 10.1161/circresaha.123.321553] [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] [Indexed: 02/03/2024]
Abstract
Cardiac arrest is the leading cause of death in the more economically developed countries. Ventricular tachycardia associated with myocardial infarct is a prominent cause of cardiac arrest. Ventricular arrhythmias occur in 3 phases of infarction: during the ischemic event, during the healing phase, and after the scar matures. Mechanisms of arrhythmias in these phases are distinct. This review focuses on arrhythmia mechanisms for ventricular tachycardia in mature myocardial scar. Available data have shown that postinfarct ventricular tachycardia is a reentrant arrhythmia occurring in circuits found in the surviving myocardial strands that traverse the scar. Electrical conduction follows a zigzag course through that area. Conduction velocity is impaired by decreased gap junction density and impaired myocyte excitability. Enhanced sympathetic tone decreases action potential duration and increases sarcoplasmic reticular calcium leak and triggered activity. These elements of the ventricular tachycardia mechanism are found diffusely throughout scar. A distinct myocyte repolarization pattern is unique to the ventricular tachycardia circuit, setting up conditions for classical reentry. Our understanding of ventricular tachycardia mechanisms continues to evolve as new data become available. The ultimate use of this information would be the development of novel diagnostics and therapeutics to reliably identify at-risk patients and prevent their ventricular arrhythmias.
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Affiliation(s)
| | - Jonathan Chrispin
- The Johns Hopkins University School of Medicine, Baltimore, MD (J.C.)
| | - Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center, David Geffen School of Medicine at UCLA, Los Angeles, CA (O.A.A.)
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3
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Chin SH, Allen E, Brack KE, Ng GA. Autonomic neuro-cardiac profile of electrical, structural and neuronal remodeling in myocardial infarction-induced heart failure. JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY PLUS 2023; 5:100044. [PMID: 37745157 PMCID: PMC10512199 DOI: 10.1016/j.jmccpl.2023.100044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 07/25/2023] [Accepted: 08/16/2023] [Indexed: 09/26/2023]
Abstract
Aims Heart failure is a clinical syndrome typified by abnormal autonomic tone, impaired ventricular function, and increased arrhythmic vulnerability. This study aims to examine electrophysiological, structural and neuronal remodeling following myocardial infarction in a rabbit heart failure model to establish its neuro-cardiac profile. Methods and results Weight-matched adult male New Zealand White rabbits (3.2 ± 0.1 kg, n = 25) were randomized to have coronary ligation surgeries (HF group, n = 13) or sham procedures (SHM group, n = 12). Transthoracic echocardiography was performed six weeks post-operatively. On week 8, dual-innervated Langendorff-perfused heart preparations were set up for terminal experiments. Seventeen hearts (HF group, n = 10) underwent ex-vivo cardiac MRI. Twenty-two hearts (HF group, n = 7) were examined histologically. Electrical remodeling and abnormal autonomic profile were evident in HF rabbits with exaggerated sympathetic and attenuated vagal effect on ventricular fibrillation threshold, ventricular refractoriness and restitution curves, in addition to increased spatial restitution dispersion. Histologically, there was significant neuronal enlargement at the heart hila and conus arteriosus in HF. Structural remodeling was characterized by quantifiable myocardial scarring, enlarged left ventricles, altered ventricular geometry and impaired contractility. Conclusion In an infarct-induced rabbit heart failure model, extensive structural, neuronal and electrophysiological remodeling in conjunction with abnormal autonomic profile provide substrates for ventricular arrhythmias.
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Affiliation(s)
- Shui Hao Chin
- Cardiology group, Department of Cardiovascular Sciences, University of Leicester, UK
- University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Emily Allen
- Cardiology group, Department of Cardiovascular Sciences, University of Leicester, UK
| | - Kieran E. Brack
- Cardiology group, Department of Cardiovascular Sciences, University of Leicester, UK
| | - G. André Ng
- Cardiology group, Department of Cardiovascular Sciences, University of Leicester, UK
- University Hospitals of Leicester NHS Trust, Leicester, UK
- NIHR Leicester Cardiovascular Biomedical Research Unit, Leicester, UK
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4
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Caldwell JL, Lee IJ, Ngo L, Wang L, Bahriz S, Xu B, Bers DM, Navedo MF, Bossuyt J, Xiang YK, Ripplinger CM. Whole-heart multiparametric optical imaging reveals sex-dependent heterogeneity in cAMP signaling and repolarization kinetics. SCIENCE ADVANCES 2023; 9:eadd5799. [PMID: 36662864 PMCID: PMC9858506 DOI: 10.1126/sciadv.add5799] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
Cyclic adenosine 3',5'-monophosphate (cAMP) is a key second messenger in cardiomyocytes responsible for transducing autonomic signals into downstream electrophysiological responses. Previous studies have shown intracellular heterogeneity and compartmentalization of cAMP signaling. However, whether cAMP signaling occurs heterogeneously throughout the intact heart and how this drives sex-dependent functional responses are unknown. Here, we developed and validated a novel cardiac-specific fluorescence resonance energy transfer-based cAMP reporter mouse and a combined voltage-cAMP whole-heart imaging system. We showed that in male hearts, cAMP was uniformly activated in response to pharmacological β-adrenergic stimulation. In contrast, female hearts showed that cAMP levels decayed faster in apical versus basal regions, which was associated with nonuniform action potential changes and notable changes in the direction of repolarization. Apical phosphodiesterase (PDE) activity was higher in female versus male hearts, and PDE inhibition prevented repolarization changes in female hearts. Thus, our imaging approach revealed sex-dependent regional breakdown of cAMP and associated electrophysiological differences.
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Affiliation(s)
| | - I-Ju Lee
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Lena Ngo
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Lianguo Wang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Sherif Bahriz
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Clinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Bing Xu
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- VA Northern California, Mather, CA, USA
| | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Manuel F. Navedo
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Julie Bossuyt
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Yang K. Xiang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- VA Northern California, Mather, CA, USA
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5
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The role of β-adrenergic stimulation in QT interval adaptation to heart rate during stress test. PLoS One 2023; 18:e0280901. [PMID: 36701349 PMCID: PMC9879473 DOI: 10.1371/journal.pone.0280901] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 01/10/2023] [Indexed: 01/27/2023] Open
Abstract
The adaptation lag of the QT interval after heart rate (HR) has been proposed as an arrhythmic risk marker. Most studies have quantified the QT adaptation lag in response to abrupt, step-like changes in HR induced by atrial pacing, in response to tilt test or during ambulatory recordings. Recent studies have introduced novel methods to quantify the QT adaptation lag to gradual, ramp-like HR changes in stress tests by evaluating the differences between the measured QT series and an estimated, memoryless QT series obtained from the instantaneous HR. These studies have observed the QT adaptation lag to progressively reduce when approaching the stress peak, with the underlying mechanisms being still unclear. This study analyzes the contribution of β-adrenergic stimulation to QT interval rate adaptation in response to gradual, ramp-like HR changes. We first quantify the QT adaptation lag in Coronary Artery Disease (CAD) patients undergoing stress test. To uncover the involved mechanisms, we use biophysically detailed computational models coupling descriptions of human ventricular electrophysiology and β-adrenergic signaling, from which we simulate ventricular action potentials and ECG signals. We characterize the adaptation of the simulated QT interval in response to the HR time series measured from each of the analyzed CAD patients. We show that, when the simulated ventricular tissue is subjected to a time-varying β-adrenergic stimulation pattern, with higher stimulation levels close to the stress peak, the simulated QT interval presents adaptation lags during exercise that are more similar to those measured from the patients than when subjected to constant β-adrenergic stimulation. During stress test recovery, constant and time-varying β-adrenergic stimulation patterns render similar adaptation lags, which are generally shorter than during exercise, in agreement with results from the patients. In conclusion, our findings support the role of time-varying β-adrenergic stimulation in contributing to QT interval adaptation to gradually increasing HR changes as those seen during the exercise phase of a stress test.
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6
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Ripplinger CM, Glukhov AV, Kay MW, Boukens BJ, Chiamvimonvat N, Delisle BP, Fabritz L, Hund TJ, Knollmann BC, Li N, Murray KT, Poelzing S, Quinn TA, Remme CA, Rentschler SL, Rose RA, Posnack NG. Guidelines for assessment of cardiac electrophysiology and arrhythmias in small animals. Am J Physiol Heart Circ Physiol 2022; 323:H1137-H1166. [PMID: 36269644 PMCID: PMC9678409 DOI: 10.1152/ajpheart.00439.2022] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/11/2022] [Accepted: 10/17/2022] [Indexed: 01/09/2023]
Abstract
Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. Although recent advances in cell-based models, including human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM), are contributing to our understanding of electrophysiology and arrhythmia mechanisms, preclinical animal studies of cardiovascular disease remain a mainstay. Over the past several decades, animal models of cardiovascular disease have advanced our understanding of pathological remodeling, arrhythmia mechanisms, and drug effects and have led to major improvements in pacing and defibrillation therapies. There exist a variety of methodological approaches for the assessment of cardiac electrophysiology and a plethora of parameters may be assessed with each approach. This guidelines article will provide an overview of the strengths and limitations of several common techniques used to assess electrophysiology and arrhythmia mechanisms at the whole animal, whole heart, and tissue level with a focus on small animal models. We also define key electrophysiological parameters that should be assessed, along with their physiological underpinnings, and the best methods with which to assess these parameters.
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Affiliation(s)
- Crystal M Ripplinger
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
| | - Alexey V Glukhov
- Department of Medicine, Cardiovascular Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia
| | - Bastiaan J Boukens
- Department Physiology, University Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Nipavan Chiamvimonvat
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
- Department of Internal Medicine, University of California Davis School of Medicine, Davis, California
- Veterans Affairs Northern California Healthcare System, Mather, California
| | - Brian P Delisle
- Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Larissa Fabritz
- University Center of Cardiovascular Science, University Heart and Vascular Center, University Hospital Hamburg-Eppendorf with DZHK Hamburg/Kiel/Luebeck, Germany
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Thomas J Hund
- Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
- Department of Biomedical Engineering, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Na Li
- Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Katherine T Murray
- Departments of Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Steven Poelzing
- Virginia Tech Carilon School of Medicine, Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech, Roanoke, Virginia
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carol Ann Remme
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Stacey L Rentschler
- Cardiovascular Division, Department of Medicine, Washington University in Saint Louis, School of Medicine, Saint Louis, Missouri
| | - Robert A Rose
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nikki G Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
- Department of Pediatrics, George Washington University School of Medicine, Washington, District of Columbia
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7
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Verkerk AO, Doszpod IJ, Mengarelli I, Magyar T, Polyák A, Pászti B, Efimov IR, Wilders R, Koncz I. Acetylcholine Reduces L-Type Calcium Current without Major Changes in Repolarization of Canine and Human Purkinje and Ventricular Tissue. Biomedicines 2022; 10:biomedicines10112987. [PMID: 36428555 PMCID: PMC9687254 DOI: 10.3390/biomedicines10112987] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/11/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022] Open
Abstract
Vagal nerve stimulation (VNS) holds a strong basis as a potentially effective treatment modality for chronic heart failure, which explains why a multicenter VNS study in heart failure with reduced ejection fraction is ongoing. However, more detailed information is required on the effect of acetylcholine (ACh) on repolarization in Purkinje and ventricular cardiac preparations to identify the advantages, risks, and underlying cellular mechanisms of VNS. Here, we studied the effect of ACh on the action potential (AP) of canine Purkinje fibers (PFs) and several human ventricular preparations. In addition, we characterized the effects of ACh on the L-type Ca2+ current (ICaL) and AP of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and performed computer simulations to explain the observed effects. Using microelectrode recordings, we found a small but significant AP prolongation in canine PFs. In the human myocardium, ACh slightly prolonged the AP in the midmyocardium but resulted in minor AP shortening in subepicardial tissue. Perforated patch-clamp experiments on hiPSC-CMs demonstrated that 5 µM ACh caused an ≈15% decrease in ICaL density without changes in gating properties. Using dynamic clamp, we found that under blocked K+ currents, 5 µM ACh resulted in an ≈23% decrease in AP duration at 90% of repolarization in hiPSC-CMs. Computer simulations using the O'Hara-Rudy human ventricular cell model revealed that the overall effect of ACh on AP duration is a tight interplay between the ACh-induced reduction in ICaL and ACh-induced changes in K+ currents. In conclusion, ACh results in minor changes in AP repolarization and duration of canine PFs and human ventricular myocardium due to the concomitant inhibition of inward ICaL and outward K+ currents, which limits changes in net repolarizing current and thus prevents major changes in AP repolarization.
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Affiliation(s)
- Arie O. Verkerk
- Department of Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Illés J. Doszpod
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
| | - Isabella Mengarelli
- Department of Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Tibor Magyar
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
| | - Alexandra Polyák
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
| | - Bence Pászti
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
| | - Igor R. Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC 20052, USA
- Department of Biomedical Engineering, Northwestern University, Chicago, IL 60611, USA
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Correspondence: (R.W.); (I.K.)
| | - István Koncz
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
- Department of Biomedical Engineering, The George Washington University, Washington, DC 20052, USA
- Correspondence: (R.W.); (I.K.)
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8
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Couch LS, Channon K, Thum T. Molecular Mechanisms of Takotsubo Syndrome. Int J Mol Sci 2022; 23:12262. [PMID: 36293121 PMCID: PMC9603071 DOI: 10.3390/ijms232012262] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 12/04/2022] Open
Abstract
Takotsubo syndrome (TTS) is a severe but reversible acute heart failure syndrome that occurs following high catecholaminergic stress. TTS patients are similar to those with acute coronary syndrome, with chest pain, dyspnoea and ST segment changes on electrocardiogram, but are characterised by apical akinesia of the left ventricle, with basal hyperkinesia in the absence of culprit coronary artery stenosis. The pathophysiology of TTS is not completely understood and there is a paucity of evidence to guide treatment. The mechanisms of TTS are thought to involve catecholaminergic myocardial stunning, microvascular dysfunction, increased inflammation and changes in cardiomyocyte metabolism. Here, we summarise the available literature to focus on the molecular basis for the pathophysiology of TTS to advance the understanding of the condition.
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Affiliation(s)
- Liam S. Couch
- Department of Cardiovascular Medicine, University of Oxford, Oxford OX1 2JD, UK
| | - Keith Channon
- Department of Cardiovascular Medicine, University of Oxford, Oxford OX1 2JD, UK
| | - Thomas Thum
- Institute of Molecular and Translational Therapeutic Strategies, Hannover Medical School, 30625 Hannover, Germany
- Fraunhofer Institute of Toxicology and Experimental Medicine, 30625 Hannover, Germany
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9
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Moss R, Wülfers EM, Lewetag R, Hornyik T, Perez-Feliz S, Strohbach T, Menza M, Krafft A, Odening KE, Seemann G. A computational model of rabbit geometry and ECG: Optimizing ventricular activation sequence and APD distribution. PLoS One 2022; 17:e0270559. [PMID: 35771854 PMCID: PMC9246225 DOI: 10.1371/journal.pone.0270559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 06/13/2022] [Indexed: 11/19/2022] Open
Abstract
Computational modeling of electrophysiological properties of the rabbit heart is a commonly used way to enhance and/or complement findings from classic lab work on single cell or tissue levels. Yet, thus far, there was no possibility to extend the scope to include the resulting body surface potentials as a way of validation or to investigate the effect of certain pathologies. Based on CT imaging, we developed the first openly available computational geometrical model not only of the whole heart but also the complete torso of the rabbit. Additionally, we fabricated a 32-lead ECG-vest to record body surface potential signals of the aforementioned rabbit. Based on the developed geometrical model and the measured signals, we then optimized the activation sequence of the ventricles, recreating the functionality of the Purkinje network, and we investigated different apico-basal and transmural gradients in action potential duration. Optimization of the activation sequence resulted in an average root mean square error between measured and simulated signal of 0.074 mV/ms for all leads. The best-fit T-Wave, compared to measured data (0.038 mV/ms), resulted from incorporating an action potential duration gradient from base to apex with a respective shortening of 20 ms and a transmural gradient with a shortening of 15 ms from endocardium to epicardium. By making our model and measured data openly available, we hope to give other researchers the opportunity to verify their research, as well as to create the possibility to investigate the impact of electrophysiological alterations on body surface signals for translational research.
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Affiliation(s)
- Robin Moss
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg ⋅ Bad Krozingen, Medical Center—University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- * E-mail:
| | - Eike M. Wülfers
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg ⋅ Bad Krozingen, Medical Center—University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Raphaela Lewetag
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg ⋅ Bad Krozingen, Medical Center—University of Freiburg, Freiburg, Germany
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany
| | - Tibor Hornyik
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg ⋅ Bad Krozingen, Medical Center—University of Freiburg, Freiburg, Germany
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, Bern, Switzerland
| | - Stefanie Perez-Feliz
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg ⋅ Bad Krozingen, Medical Center—University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany
| | - Tim Strohbach
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | - Marius Menza
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | - Axel Krafft
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | - Katja E. Odening
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, Bern, Switzerland
| | - Gunnar Seemann
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg ⋅ Bad Krozingen, Medical Center—University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
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10
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Xia R, Tomsits P, Loy S, Zhang Z, Pauly V, Schüttler D, Clauss S. Cardiac Macrophages and Their Effects on Arrhythmogenesis. Front Physiol 2022; 13:900094. [PMID: 35812333 PMCID: PMC9257039 DOI: 10.3389/fphys.2022.900094] [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: 03/19/2022] [Accepted: 05/30/2022] [Indexed: 12/24/2022] Open
Abstract
Cardiac electrophysiology is a complex system established by a plethora of inward and outward ion currents in cardiomyocytes generating and conducting electrical signals in the heart. However, not only cardiomyocytes but also other cell types can modulate the heart rhythm. Recently, cardiac macrophages were demonstrated as important players in both electrophysiology and arrhythmogenesis. Cardiac macrophages are a heterogeneous group of immune cells including resident macrophages derived from embryonic and fetal precursors and recruited macrophages derived from circulating monocytes from the bone marrow. Recent studies suggest antiarrhythmic as well as proarrhythmic effects of cardiac macrophages. The proposed mechanisms of how cardiac macrophages affect electrophysiology vary and include both direct and indirect interactions with other cardiac cells. In this review, we provide an overview of the different subsets of macrophages in the heart and their possible interactions with cardiomyocytes under both physiologic conditions and heart disease. Furthermore, we elucidate similarities and differences between human, murine and porcine cardiac macrophages, thus providing detailed information for researchers investigating cardiac macrophages in important animal species for electrophysiologic research. Finally, we discuss the pros and cons of mice and pigs to investigate the role of cardiac macrophages in arrhythmogenesis from a translational perspective.
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Affiliation(s)
- Ruibing Xia
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Philipp Tomsits
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Simone Loy
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Zhihao Zhang
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Valerie Pauly
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Dominik Schüttler
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Sebastian Clauss
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
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11
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Zhu C, Rajendran PS, Hanna P, Efimov IR, Salama G, Fowlkes CC, Shivkumar K. High-resolution structure-function mapping of intact hearts reveals altered sympathetic control of infarct border zones. JCI Insight 2022; 7:153913. [PMID: 35132963 PMCID: PMC8855798 DOI: 10.1172/jci.insight.153913] [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] [Indexed: 01/09/2023] Open
Abstract
Remodeling of injured sympathetic nerves on the heart after myocardial infarction (MI) contributes to adverse outcomes such as sudden arrhythmic death, yet the underlying structural mechanisms are poorly understood. We sought to examine microstructural changes on the heart after MI and to directly link these changes with electrical dysfunction. We developed a high-resolution pipeline for anatomically precise alignment of electrical maps with structural myofiber and nerve-fiber maps created by customized computer vision algorithms. Using this integrative approach in a mouse model, we identified distinct structure-function correlates to objectively delineate the infarct border zone, a known source of arrhythmias after MI. During tyramine-induced sympathetic nerve activation, we demonstrated regional patterns of altered electrical conduction aligned directly with altered neuroeffector junction distribution, pointing to potential neural substrates for cardiac arrhythmia. This study establishes a synergistic framework for examining structure-function relationships after MI with microscopic precision that has potential to advance understanding of arrhythmogenic mechanisms.
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Affiliation(s)
- Ching Zhu
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Pradeep S Rajendran
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Peter Hanna
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA
| | - Guy Salama
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Charless C Fowlkes
- Department of Computer Science, University of California, Irvine, Irvine, California, USA
| | - Kalyanam Shivkumar
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
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12
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Walsh-Wilkinson E, Arsenault M, Couet J. Segmental analysis by speckle-tracking echocardiography of the left ventricle response to isoproterenol in male and female mice. PeerJ 2021; 9:e11085. [PMID: 33763310 PMCID: PMC7958899 DOI: 10.7717/peerj.11085] [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: 11/13/2020] [Accepted: 02/18/2021] [Indexed: 01/03/2023] Open
Abstract
We studied by conventional and speckle-tracking echocardiography, the response of the left ventricle (LV) to a three-week continuous infusion of isoproterenol (Iso), a non-specific beta-adrenergic receptor agonist in male and female C57Bl6/J mice. Before and after Iso (30 mg/kg/day), we characterized LV morphology and function as well as global and segmental strain. We observed that Iso reduced LV ejection in both male (−8.7%) and female (−14.7%) mice. Several diastolic function parameters were negatively regulated in males and females such as E/A, E/E′, isovolumetric relaxation time. Global longitudinal (GLS) and circumferential (GCS) strains were reduced by Iso in both sexes, GLS by 31% and GCS by about 20%. For the segmental LV analysis, we measured strain, strain rate, reverse strain rate, peak speckle displacement and peak speckle velocity in the parasternal long axis. We observed that radial strain of the LV posterior segments were more severely modulated by Iso than those of the anterior wall in males. In females, on the other hand, both posterior and anterior wall segments were negatively impacted by Iso. Longitudinal strain showed similar results to the radial strain for both sexes. Strain rate, on the other hand, was only moderately changed by Iso. Reverse strain rate measurements (an index of diastolic function) showed that posterior LV segments were negatively regulated by Iso. We then studied the animals 5 and 17 weeks after Iso treatment. Compared to control mice, LV dilation was still present in males. Ejection fraction was decreased in mice of both sex compared to control animals. Diastolic function parameters, on the other hand, were back to normal. Taken together, our study indicates that segmental strain analysis can identify LV regions that are more negatively affected by a cardiotoxic agent such as Iso. In addition, cessation of Iso was not accompanied with a complete restoration of cardiac function after four months.
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Affiliation(s)
- Elisabeth Walsh-Wilkinson
- Universite Laval, Groupe de recherche sur les valvulopathies, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Quebec, Quebec, Canada
| | - Marie Arsenault
- Universite Laval, Groupe de recherche sur les valvulopathies, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Quebec, Quebec, Canada
| | - Jacques Couet
- Universite Laval, Groupe de recherche sur les valvulopathies, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Quebec, Quebec, Canada
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13
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Fei YD, Chen M, Guo S, Ueoka A, Chen Z, Rubart-von der Lohe M, Everett TH, Qu Z, Weiss JN, Chen PS. Simultaneous activation of the small conductance calcium-activated potassium current by acetylcholine and inhibition of sodium current by ajmaline cause J-wave syndrome in Langendorff-perfused rabbit ventricles. Heart Rhythm 2021; 18:98-108. [PMID: 32763429 PMCID: PMC7796982 DOI: 10.1016/j.hrthm.2020.07.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 07/24/2020] [Accepted: 07/30/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND Concomitant apamin-sensitive small conductance calcium-activated potassium current (IKAS) activation and sodium current inhibition induce J-wave syndrome (JWS) in rabbit hearts. Sudden death in JWS occurs predominantly in men at night when parasympathetic tone is strong. OBJECTIVE The purpose of this study was to test the hypotheses that acetylcholine (ACh), the parasympathetic transmitter, activates IKAS and causes JWS in the presence of ajmaline. METHODS We performed optical mapping in Langendorff-perfused rabbit hearts and whole-cell voltage clamp to determine IKAS in isolated ventricular cardiomyocytes. RESULTS ACh (1 μM) + ajmaline (2 μM) induced J-point elevations in all (6 male and 6 female) hearts from 0.01± 0.01 to 0.31 ± 0.05 mV (P<.001), which were reduced by apamin (specific IKAS inhibitor, 100 nM) to 0.14 ± 0.02 mV (P<.001). More J-point elevation was noted in male than in female hearts (P=.037). Patch clamp studies showed that ACh significantly (P<.001) activated IKAS in isolated male but not in female ventricular myocytes (n=8). Optical mapping studies showed that ACh induced action potential duration (APD) heterogeneity, which was more significant in right than in left ventricles. Apamin in the presence of ACh prolonged both APD at the level of 25% (P<.001) and APD at the level of 80% (P<.001) and attenuated APD heterogeneity. Ajmaline further increased APD heterogeneity induced by ACh. Ventricular arrhythmias were induced in 6 of 6 male and 1 of 6 female hearts (P=.015) in the presence of ACh and ajmaline, which was significantly suppressed by apamin in the former. CONCLUSION ACh activates ventricular IKAS. ACh and ajmaline induce JWS and facilitate the induction of ventricular arrhythmias more in male than in female ventricles.
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Affiliation(s)
- Yu-Dong Fei
- Krannert Institute of Cardiology, Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Cardiology, XinHua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mu Chen
- Krannert Institute of Cardiology, Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Cardiology, XinHua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shuai Guo
- Krannert Institute of Cardiology, Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Akira Ueoka
- Krannert Institute of Cardiology, Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Zhenhui Chen
- Krannert Institute of Cardiology, Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Michael Rubart-von der Lohe
- Department of Pediatrics, Riley Heart Research Center, Indiana University School of Medicine, Indianapolis, Indiana
| | - Thomas H Everett
- Krannert Institute of Cardiology, Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Zhilin Qu
- Department of Medicine (Cardiology) and Physiology, University of California, Los Angeles, California
| | - James N Weiss
- Department of Medicine (Cardiology) and Physiology, University of California, Los Angeles, California
| | - Peng-Sheng Chen
- Krannert Institute of Cardiology, Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Cedars-Sinai Medical Center, Los Angeles, California.
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14
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Chen M, Li X, Wang S, Yu L, Tang J, Zhou S. The Role of Cardiac Macrophage and Cytokines on Ventricular Arrhythmias. Front Physiol 2020; 11:1113. [PMID: 33071805 PMCID: PMC7540080 DOI: 10.3389/fphys.2020.01113] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022] Open
Abstract
In the heart, cardiac macrophages have widespread biological functions, including roles in antigen presentation, phagocytosis, and immunoregulation, through the formation of diverse cytokines and growth factors; thus, these cells play an active role in tissue repair after heart injury. Recent clinical studies have indicated that macrophages or elevated inflammatory cytokines secreted by macrophages are closely related to ventricular arrhythmias (VAs). This review describes the role of macrophages and macrophage-secreted inflammatory cytokines in ventricular arrhythmogenesis.
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Affiliation(s)
- Mingxian Chen
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Xuping Li
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Songyun Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lilei Yu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jianjun Tang
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Shenghua Zhou
- The Second Xiangya Hospital, Central South University, Changsha, China
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15
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Saadeh K, Shivkumar K, Jeevaratnam K. Targeting the β-adrenergic receptor in the clinical management of congenital long QT syndrome. Ann N Y Acad Sci 2020; 1474:27-46. [PMID: 32901453 DOI: 10.1111/nyas.14425] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/10/2020] [Accepted: 06/09/2020] [Indexed: 01/01/2023]
Abstract
The long QT syndrome (LQTS) is largely treated pharmacologically with β-blockers, despite the role of sympathetic activity in LQTS being poorly understood. Using the trigger-substrate model of cardiac arrhythmias in this review, we amalgamate current experimental and clinical data from both animal and human studies to explain the mechanism of adrenergic stimulation and blockade on LQT arrhythmic risk and hence assess the efficacy of β-adrenoceptor blockade in the management of LQTS. In LQTS1 and LQTS2, sympathetic stimulation increases arrhythmic risk by enhancing early afterdepolarizations and transmural dispersion of repolarization. β-Blockers successfully reduce cardiac events by reducing these triggers and substrates; however, these effects are less marked in LQTS2 compared with LQTS1. In LQTS3, clinical and experimental investigations of the effects of sympathetic stimulation and β-blocker use have produced contradictory findings, resulting in significant clinical uncertainty. We offer explanations for these contradicting results relating to study sample size, the dose of the β-blocker administered associated with its off-target Na+ channel effects, as well as the type of β-blocker used. We conclude that the antiarrhythmic efficacy of β-blockers is a genotype-specific phenomenon, and hence the use of β-blockers in clinical practice should be genotype dependent.
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Affiliation(s)
- Khalil Saadeh
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Centre, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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16
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Clayton RH, Aboelkassem Y, Cantwell CD, Corrado C, Delhaas T, Huberts W, Lei CL, Ni H, Panfilov AV, Roney C, dos Santos RW. An audit of uncertainty in multi-scale cardiac electrophysiology models. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190335. [PMID: 32448070 PMCID: PMC7287340 DOI: 10.1098/rsta.2019.0335] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/16/2020] [Indexed: 05/21/2023]
Abstract
Models of electrical activation and recovery in cardiac cells and tissue have become valuable research tools, and are beginning to be used in safety-critical applications including guidance for clinical procedures and for drug safety assessment. As a consequence, there is an urgent need for a more detailed and quantitative understanding of the ways that uncertainty and variability influence model predictions. In this paper, we review the sources of uncertainty in these models at different spatial scales, discuss how uncertainties are communicated across scales, and begin to assess their relative importance. We conclude by highlighting important challenges that continue to face the cardiac modelling community, identifying open questions, and making recommendations for future studies. This article is part of the theme issue 'Uncertainty quantification in cardiac and cardiovascular modelling and simulation'.
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Affiliation(s)
- Richard H. Clayton
- Insigneo institute for in-silico Medicine and Department of Computer Science, University of Sheffield, Sheffield, UK
- e-mail:
| | - Yasser Aboelkassem
- Department of Bioengineering, University of California, San Diego, CA, USA
| | | | - Cesare Corrado
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
| | - Tammo Delhaas
- School of Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Wouter Huberts
- School of Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Chon Lok Lei
- Computational Biology and Health Informatics, Department of Computer Science, University of Oxford, Oxford, UK
| | - Haibo Ni
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Alexander V. Panfilov
- Department of Physics and Astronomy, University of Gent, Gent, Belgium
- Laboratory of Computational Biology and Medicine, Ural Federal University, Ekaterinburg, Russia
| | - Caroline Roney
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
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17
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Ang R, Marina N. Low-Frequency Oscillations in Cardiac Sympathetic Neuronal Activity. Front Physiol 2020; 11:236. [PMID: 32256390 PMCID: PMC7093552 DOI: 10.3389/fphys.2020.00236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/02/2020] [Indexed: 12/25/2022] Open
Abstract
Sudden cardiac death caused by ventricular arrhythmias is among the leading causes of mortality, with approximately half of all deaths attributed to heart disease worldwide. Periodic repolarization dynamics (PRD) is a novel marker of repolarization instability and strong predictor of death in patients post-myocardial infarction that is believed to occur in association with low-frequency oscillations in sympathetic nerve activity. However, this hypothesis is based on associations of PRD with indices of sympathetic activity that are not directly linked to cardiac function, such as muscle vasoconstrictor activity and the variability of cardiovascular autospectra. In this review article, we critically evaluate existing scientific evidence obtained primarily in experimental animal models, with the aim of identifying the neuronal networks responsible for the generation of low-frequency sympathetic rhythms along the neurocardiac axis. We discuss the functional significance of rhythmic sympathetic activity on neurotransmission efficacy and explore its role in the pathogenesis of ventricular repolarization instability. Most importantly, we discuss important gaps in our knowledge that require further investigation in order to confirm the hypothesis that low frequency cardiac sympathetic oscillations play a causative role in the generation of PRD.
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Affiliation(s)
- Richard Ang
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Nephtali Marina
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.,Division of Medicine, University College London, London, United Kingdom
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18
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Kim TY, Jeng P, Hwang J, Pfeiffer Z, Patel D, Cooper LL, Kossidas K, Centracchio J, Peng X, Koren G, Qu Z, Choi BR. Short-Long Heart Rate Variation Increases Dispersion of Action Potential Duration in Long QT Type 2 Transgenic Rabbit Model. Sci Rep 2019; 9:14849. [PMID: 31619700 PMCID: PMC6795902 DOI: 10.1038/s41598-019-51230-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/24/2019] [Indexed: 01/21/2023] Open
Abstract
The initiation of polymorphic ventricular tachycardia in long QT syndrome type 2 (LQT2) has been associated with a characteristic ECG pattern of short-long RR intervals. We hypothesize that this characteristic pattern increases APD dispersion in LQT2, thereby promoting arrhythmia. We investigated APD dispersion and its dependence on two previous cycle lengths (CLs) in transgenic rabbit models of LQT2, LQT1, and their littermate controls (LMC) using random stimulation protocols. The results show that the short-long RR pattern was associated with a larger APD dispersion in LQT2 but not in LQT1 rabbits. The multivariate analyses of APD as a function of two previous CLs (APDn = C + α1CLn−1 + α2CLn−2) showed that α1 (APD restitution slope) is largest and heterogeneous in LQT2 but uniform in LQT1, enhancing APD dispersion under long CLn−1 in LQT2. The α2 (short-term memory) was negative in LQT2 while positive in LQT1, and the spatial pattern of α1 was inversely correlated to α2 in LQT2, which explains why a short-long combination causes a larger APD dispersion in LQT2 but not in LQT1 rabbits. In conclusion, short-long RR pattern increased APD dispersion only in LQT2 rabbits through heterogeneous APD restitution and the short-term memory, underscoring the genotype-specific triggering of arrhythmias in LQT syndrome.
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Affiliation(s)
- Tae Yun Kim
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul Jeng
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - JungMin Hwang
- College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | - Zachary Pfeiffer
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Divyang Patel
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Leroy L Cooper
- Biology Department, Vassar College, Poughkeepsie, NY, USA
| | - Konstantinos Kossidas
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Jason Centracchio
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Xuwen Peng
- Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Gideon Koren
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Zhilin Qu
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Bum-Rak Choi
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA.
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19
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Manabe O, Naya M, Oyama-Manabe N, Koyanagawa K, Tamaki N. The role of multimodality imaging in takotsubo cardiomyopathy. J Nucl Cardiol 2019; 26:1602-1616. [PMID: 29858766 DOI: 10.1007/s12350-018-1312-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 05/01/2018] [Indexed: 12/14/2022]
Abstract
Takotsubo cardiomyopathy (TC) is a syndrome of transient left ventricular (LV) dysfunction mimicking acute coronary syndrome. Although the mechanisms underlying the occurrence of TC are unknown, several imaging techniques contribute to its diagnosis. Here we review the current knowledge about TC, in particular, the pathophysiology and the role of imaging including nuclear cardiovascular medicine.
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Affiliation(s)
- Osamu Manabe
- Department of Nuclear Medicine, Hokkaido University of Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Masanao Naya
- Department of Cardiovascular Medicine, Hokkaido University of Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
| | - Noriko Oyama-Manabe
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Japan
| | - Kazuhiro Koyanagawa
- Department of Cardiovascular Medicine, Hokkaido University of Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Nagara Tamaki
- Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
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20
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Wright PT, Bhogal NK, Diakonov I, Pannell LMK, Perera RK, Bork NI, Schobesberger S, Lucarelli C, Faggian G, Alvarez-Laviada A, Zaccolo M, Kamp TJ, Balijepalli RC, Lyon AR, Harding SE, Nikolaev VO, Gorelik J. Cardiomyocyte Membrane Structure and cAMP Compartmentation Produce Anatomical Variation in β 2AR-cAMP Responsiveness in Murine Hearts. Cell Rep 2019; 23:459-469. [PMID: 29642004 PMCID: PMC5912947 DOI: 10.1016/j.celrep.2018.03.053] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 02/02/2018] [Accepted: 03/13/2018] [Indexed: 01/19/2023] Open
Abstract
Cardiomyocytes from the apex but not the base of the heart increase their contractility in response to β2-adrenoceptor (β2AR) stimulation, which may underlie the development of Takotsubo cardiomyopathy. However, both cell types produce comparable cytosolic amounts of the second messenger cAMP. We investigated this discrepancy using nanoscale imaging techniques and found that, structurally, basal cardiomyocytes have more organized membranes (higher T-tubular and caveolar densities). Local membrane microdomain responses measured in isolated basal cardiomyocytes or in whole hearts revealed significantly smaller and more short-lived β2AR/cAMP signals. Inhibition of PDE4, caveolar disruption by removing cholesterol or genetic deletion of Cav3 eliminated differences in local cAMP production and equilibrated the contractile response to β2AR. We conclude that basal cells possess tighter control of cAMP because of a higher degree of signaling microdomain organization. This provides varying levels of nanostructural control for cAMP-mediated functional effects that orchestrate macroscopic, regional physiological differences within the heart. Cardiomyocyte membrane organization varies in degree between regions of the heart Differences in structural organization affect adrenergic signaling via β2AR Reduced organization allows β2AR-cAMP to influence contractility in myocardial apex Variability in cell structure may allow differential response of heart regions
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Affiliation(s)
- Peter T Wright
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Navneet K Bhogal
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Ivan Diakonov
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Laura M K Pannell
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Ruwan K Perera
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Nadja I Bork
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Sophie Schobesberger
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK; Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Carla Lucarelli
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK; Department of Cardiac Surgery, University of Verona School of Medicine, Azienda Ospedalieria Universitaria Integrata, Borgo Trento Piazzale A. Stefani, 37126 Verona, Italy
| | - Giuseppe Faggian
- Department of Cardiac Surgery, University of Verona School of Medicine, Azienda Ospedalieria Universitaria Integrata, Borgo Trento Piazzale A. Stefani, 37126 Verona, Italy
| | - Anita Alvarez-Laviada
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Timothy J Kamp
- Department of Medicine, University of Wisconsin Madison, 1111 Highland Ave., Madison, WI 53705-2275, USA
| | - Ravi C Balijepalli
- Department of Medicine, University of Wisconsin Madison, 1111 Highland Ave., Madison, WI 53705-2275, USA
| | - Alexander R Lyon
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK; NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London SW7 3AZ, UK
| | - Sian E Harding
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Julia Gorelik
- Myocardial Function, National Heart and Lung Institute, Imperial College London, ICTEM, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
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21
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Wang L, Morotti S, Tapa S, Francis Stuart SD, Jiang Y, Wang Z, Myles RC, Brack KE, Ng GA, Bers DM, Grandi E, Ripplinger CM. Different paths, same destination: divergent action potential responses produce conserved cardiac fight-or-flight response in mouse and rabbit hearts. J Physiol 2019; 597:3867-3883. [PMID: 31215643 DOI: 10.1113/jp278016] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 06/17/2019] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Cardiac electrophysiology and Ca2+ handling change rapidly during the fight-or-flight response to meet physiological demands. Despite dramatic differences in cardiac electrophysiology, the cardiac fight-or-flight response is highly conserved across species. In this study, we performed physiological sympathetic nerve stimulation (SNS) while optically mapping cardiac action potentials and intracellular Ca2+ transients in innervated mouse and rabbit hearts. Despite similar heart rate and Ca2+ handling responses between mouse and rabbit hearts, we found notable species differences in spatio-temporal repolarization dynamics during SNS. Species-specific computational models revealed that these electrophysiological differences allowed for enhanced Ca2+ handling (i.e. enhanced inotropy) in each species, suggesting that electrophysiological responses are fine-tuned across species to produce optimal cardiac fight-or-flight responses. ABSTRACT Sympathetic activation of the heart results in positive chronotropy and inotropy, which together rapidly increase cardiac output. The precise mechanisms that produce the electrophysiological and Ca2+ handling changes underlying chronotropic and inotropic responses have been studied in detail in isolated cardiac myocytes. However, few studies have examined the dynamic effects of physiological sympathetic nerve activation on cardiac action potentials (APs) and intracellular Ca2+ transients (CaTs) in the intact heart. Here, we performed bilateral sympathetic nerve stimulation (SNS) in fully innervated, Langendorff-perfused rabbit and mouse hearts. Dual optical mapping with voltage- and Ca2+ -sensitive dyes allowed for analysis of spatio-temporal AP and CaT dynamics. The rabbit heart responded to SNS with a monotonic increase in heart rate (HR), monotonic decreases in AP and CaT duration (APD, CaTD), and a monotonic increase in CaT amplitude. The mouse heart had similar HR and CaT responses; however, a pronounced biphasic APD response occurred, with initial prolongation (50.9 ± 5.1 ms at t = 0 s vs. 60.6 ± 4.1 ms at t = 15 s, P < 0.05) followed by shortening (46.5 ± 9.1 ms at t = 60 s, P = NS vs. t = 0). We determined the biphasic APD response in mouse was partly due to dynamic changes in HR during SNS and was exacerbated by β-adrenergic activation. Simulations with species-specific cardiac models revealed that transient APD prolongation in mouse allowed for greater and more rapid CaT responses, suggesting more rapid increases in contractility; conversely, the rabbit heart requires APD shortening to produce optimal inotropic responses. Thus, while the cardiac fight-or-flight response is highly conserved between species, the underlying mechanisms orchestrating these effects differ significantly.
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Affiliation(s)
- Lianguo Wang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Stefano Morotti
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Srinivas Tapa
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | | | - Yanyan Jiang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Zhen Wang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Rachel C Myles
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | - Kieran E Brack
- Department of Cardiovascular Sciences, University of Leicester, NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - G André Ng
- Department of Cardiovascular Sciences, University of Leicester, NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Donald M Bers
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Eleonora Grandi
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Crystal M Ripplinger
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
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22
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The electrocardiogram of vertebrates: Evolutionary changes from ectothermy to endothermy. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 144:16-29. [DOI: 10.1016/j.pbiomolbio.2018.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/09/2018] [Accepted: 08/13/2018] [Indexed: 12/11/2022]
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23
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The autonomic nervous system and cardiac arrhythmias: current concepts and emerging therapies. Nat Rev Cardiol 2019; 16:707-726. [DOI: 10.1038/s41569-019-0221-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/07/2019] [Indexed: 12/19/2022]
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24
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Carnevali L, Statello R, Sgoifo A. Resting Heart Rate Variability Predicts Vulnerability to Pharmacologically-Induced Ventricular Arrhythmias in Male Rats. J Clin Med 2019; 8:jcm8050655. [PMID: 31083474 PMCID: PMC6572182 DOI: 10.3390/jcm8050655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 12/03/2022] Open
Abstract
The electrical stability of the myocardium is dependent on the dynamic balance between sympathetic and parasympathetic influences on the heart, which is reflected by heart rate variability (HRV). Reduced HRV is a proposed predictor of sudden death caused by ventricular tachyarrhythmias in cardiac patients. However, the link between individual differences in HRV and ventricular tachyarrhythmic risk in populations without known pre-existing cardiac conditions is less well explored. In this study we investigated the extent to which individual differences in resting state HRV predict susceptibility to spontaneous and pharmacologically-induced ventricular arrhythmias in healthy rats. Radiotelemetric transmitters were implanted in 42 adult male Wild-type Groningen rats. ECG signals were recorded during 24-h resting conditions and under β-adrenoceptor pharmacological stimulation with isoproterenol and analyzed by means of time- and frequency-domain indexes of HRV. No significant association was found between individual differences in resting measures of HRV and spontaneous incidence of ventricular arrhythmias. However, lower resting values of HRV predicted a higher number of ventricular ectopic beats following β-adrenergic pharmacological stimulation with isoproterenol (0.02 mg/kg). Moreover, after isoproterenol administration, one rat with low resting HRV developed sustained ventricular tachycardia that led to death. The present results might be indicative of the potential utility of HRV measures of resting cardiac autonomic function for the prediction of ventricular arrhythmias, particularly during conditions of strong sympathetic activation, in populations without known cardiac disease.
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Affiliation(s)
- Luca Carnevali
- Stress Physiology Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43121 Parma, Italy.
| | - Rosario Statello
- Stress Physiology Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43121 Parma, Italy.
| | - Andrea Sgoifo
- Stress Physiology Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43121 Parma, Italy.
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25
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Tomek J, Hao G, Tomková M, Lewis A, Carr C, Paterson DJ, Rodriguez B, Bub G, Herring N. β-Adrenergic Receptor Stimulation and Alternans in the Border Zone of a Healed Infarct: An ex vivo Study and Computational Investigation of Arrhythmogenesis. Front Physiol 2019; 10:350. [PMID: 30984029 PMCID: PMC6450465 DOI: 10.3389/fphys.2019.00350] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/14/2019] [Indexed: 12/21/2022] Open
Abstract
Background: Following myocardial infarction (MI), the myocardium is prone to calcium-driven alternans, which typically precedes ventricular tachycardia and fibrillation. MI is also associated with remodeling of the sympathetic innervation in the infarct border zone, although how this influences arrhythmogenesis is controversial. We hypothesize that the border zone is most vulnerable to alternans, that β-adrenergic receptor stimulation can suppresses this, and investigate the consequences in terms of arrhythmogenic mechanisms. Methods and Results: Anterior MI was induced in Sprague-Dawley rats (n = 8) and allowed to heal over 2 months. This resulted in scar formation, significant (p < 0.05) dilation of the left ventricle, and reduction in ejection fraction compared to sham operated rats (n = 4) on 7 T cardiac magnetic resonance imaging. Dual voltage/calcium optical mapping of post-MI Langendorff perfused hearts (using RH-237 and Rhod2) demonstrated that the border zone was significantly more prone to alternans than the surrounding myocardium at longer cycle lengths, predisposing to spatially heterogeneous alternans. β-Adrenergic receptor stimulation with norepinephrine (1 μmol/L) attenuated alternans by 60 [52–65]% [interquartile range] and this was reversed with metoprolol (10 μmol/L, p = 0.008). These results could be reproduced by computer modeling of the border zone based on our knowledge of β-adrenergic receptor signaling pathways and their influence on intracellular calcium handling and ion channels. Simulations also demonstrated that β-adrenergic receptor stimulation in this specific region reduced the formation of conduction block and the probability of premature ventricular activation propagation. Conclusion: While high levels of overall cardiac sympathetic drive are a negative prognostic indicator of mortality following MI and during heart failure, β-adrenergic receptor stimulation in the infarct border zone reduced spatially heterogeneous alternans, and prevented conduction block and propagation of extrasystoles. This may help explain recent clinical imaging studies using meta-iodobenzylguanidine (MIBG) and 11C-meta-hydroxyephedrine positron emission tomography (PET) which demonstrate that border zone denervation is strongly associated with a high risk of future arrhythmia.
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Affiliation(s)
- Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Guoliang Hao
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Markéta Tomková
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Andrew Lewis
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Carolyn Carr
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - David J Paterson
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Gil Bub
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Neil Herring
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
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26
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Francis Stuart SD, Wang L, Woodard WR, Ng GA, Habecker BA, Ripplinger CM. Age-related changes in cardiac electrophysiology and calcium handling in response to sympathetic nerve stimulation. J Physiol 2018; 596:3977-3991. [PMID: 29938794 DOI: 10.1113/jp276396] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/22/2018] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Ageing results in changes to cardiac electrophysiology, Ca2+ handling, and β-adrenergic responsiveness. Sympathetic neurodegeneration also occurs with age, yet detailed action potential and Ca2+ handling responses to physiological sympathetic nerve stimulation (SNS) in the aged heart have not been assessed. Optical mapping in mouse hearts with intact sympathetic innervation revealed reduced responsiveness to SNS in the aged atria (assessed by heart rate) and aged ventricles (assessed by action potentials and Ca2+ transients). Sympathetic nerve density and noradrenaline content were reduced in aged ventricles, but noradrenaline content was preserved in aged atria. These results demonstrate that reduced responsiveness to SNS in the atria may be primarily due to decreased β-adrenergic receptor responsiveness, whereas reduced responsiveness to SNS in the ventricles may be primarily due to neurodegeneration. ABSTRACT The objective of this study was to determine how age-related changes in sympathetic structure and function impact cardiac electrophysiology and intracellular Ca2+ handling. Innervated hearts from young (3-4 months, YWT, n = 10) and aged (20-24 months, AGED, n = 11) female mice (C57Bl6) were optically mapped using the voltage (Vm ,)- and calcium (Ca2+ )-sensitive indicators Rh237 and Rhod2-AM. Sympathetic nerve stimulation (SNS) was performed at the spinal cord (T1-T3). β-Adrenergic responsiveness was assessed with isoproterenol (1 μM, ISO). Sympathetic nerve density and noradrenaline content were also quantified. Stimulation thresholds necessary to produce a defined increase in heart rate (HR) with SNS were higher in AGED vs. YWT hearts (5.4 ± 0.4 vs. 3.8 ± 0.4 Hz, P < 0.05). Maximal HR with SNS was lower in AGED vs. YWT (20.5 ± 3.41% vs. 73.0 ± 7.63% increase, P < 0.05). β-Adrenergic responsiveness of the atria (measured as percentage increase in HR with ISO) was decreased in AGED vs. YWT hearts (75.3 ± 22.5% vs. 148.5 ± 19.8%, P < 0.05). SNS significantly increased action potential duration (APD) in YWT but not AGED. Ca2+ transient durations and rise times were unchanged by SNS, yet AGED hearts had an increased susceptibility to Ca2+ alternans and ventricular arrhythmias. β-Adrenergic responsiveness of all ventricular parameters were similar between AGED and YWT. Sympathetic nerve density and noradrenaline content were decreased in the AGED ventricle, but not atria, compared to YWT. These data suggest that decreased responsiveness to SNS in the aged atria may be primarily due to decreased β-adrenergic responsiveness, whereas decreased responsiveness to SNS in the aged ventricles may be primarily due to nerve degeneration.
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Affiliation(s)
| | - Lianguo Wang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - William R Woodard
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
| | - G Andre Ng
- Department of Cardiovascular Sciences, University of Leicester, NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Beth A Habecker
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
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27
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Chauhan RA, Coote J, Allen E, Pongpaopattanakul P, Brack KE, Ng GA. Functional selectivity of cardiac preganglionic sympathetic neurones in the rabbit heart. Int J Cardiol 2018; 264:70-78. [PMID: 29657079 PMCID: PMC5968349 DOI: 10.1016/j.ijcard.2018.03.119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/21/2018] [Accepted: 03/26/2018] [Indexed: 01/26/2023]
Abstract
BACKGROUND Studies have shown regional and functional selectivity of cardiac postganglionic neurones indicating there might exist a similar heterogeneity in spinal segmental preganglionic neurones, which requires further investigation. METHODS Right and left sympathetic chains were electrically stimulated from T6 to T1 in the innervated isolated rabbit heart preparation (n = 18). Sinus rate, left ventricular pressure, retrograde ventriculo-atrial conduction, monophasic action potential duration, effective refractory period, ventricular fibrillation threshold and electrical restitution were measured. RESULTS Right sympathetic stimulation had a greater influence on heart rate (T1-T2: right; 59.9 ± 6.0%, left; 41.1 ± 5.6% P < 0.001) and left stimulation had greater effects on left ventricular pressure (T1-T2: right; 20.7 ± 3.2%, left; 40.3 ± 5.4%, P < 0.01) and ventriculo-atrial conduction (T1-T2: right; -6.8 ± 1.1%, left; -15.5 ± 0.2%) at all levels, with greater effects at rostral levels (T1-T3). Left sympathetic stimulation caused shorter monophasic action potentials at the base (T4-T5: right; 119.3 ± 2.7 ms, left; 114.7 ± 2.5 ms. P < 0.05) and apex (T4-T5: right; 118.8 ± 1.2 ms, left; 114.6 ± 2.6 ms. P < 0.05), greater shortening of effective refractory period (T4-T5: right; -3.6 ± 1.3%, left; -7.7 ± 1.8%. P < 0.05), a steeper maximum slope of restitution (T4-T5 base: right; 1.3 ± 0.2, left; 1.8 ± 0.2. P < 0.01. T4-T5 apex: right; 1.0 ± 0.2, left; 1.6 ± 0.3. P < 0.05) and a greater decrease in ventricular fibrillation threshold (T4-T5: right; -22.3 ± 6.8%, left;-39.0 ± 1.7%), with dominant effects at caudal levels (T4-T6). CONCLUSIONS The preganglionic sympathetic efferent axons show functionally distinct pathways to the heart. The caudal segments (T4-T6) of the left sympathetic chain had a greater potential for arrhythmia generation and hence could pose a target for more focused clinical treatments for impairments in cardiac function.
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Affiliation(s)
- Reshma A Chauhan
- Department of Cardiovascular Sciences, University of Leicester, UK
| | - John Coote
- Department of Cardiovascular Sciences, University of Leicester, UK; University of Birmingham, UK
| | - Emily Allen
- Department of Cardiovascular Sciences, University of Leicester, UK
| | | | - Kieran E Brack
- Department of Cardiovascular Sciences, University of Leicester, UK
| | - G Andre Ng
- Department of Cardiovascular Sciences, University of Leicester, UK; NIHR Leicester Biomedical Research Centre, Leicester, UK; University Hospitals of Leicester NHS Trust, Leicester, UK.
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28
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Li Y, Zhang X, Zhang C, Zhang X, Li Y, Qi Z, Szeto C, Tang M, Peng Y, Molkentin JD, Houser SR, Xie M, Chen X. Increasing T-type calcium channel activity by β-adrenergic stimulation contributes to β-adrenergic regulation of heart rates. J Physiol 2018; 596:1137-1151. [PMID: 29274077 PMCID: PMC5878229 DOI: 10.1113/jp274756] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 12/13/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Cav3.1 T-type Ca2+ channel current (ICa-T ) contributes to heart rate genesis but is not known to contribute to heart rate regulation by the sympathetic/β-adrenergic system (SAS). We show that the loss of Cav3.1 makes the beating rates of the heart in vivo and perfused hearts ex vivo, as well as sinoatrial node cells, less sensitive to β-adrenergic stimulation; it also renders less conduction acceleration through the atrioventricular node by β-adrenergic stimulation. Increasing Cav3.1 in cardiomyocytes has the opposite effects. ICa-T in sinoatrial nodal cells can be upregulated by β-adrenergic stimulation. The results of the present study add a new contribution to heart rate regulation by the SAS system and provide potential new mechanisms for the dysregulation of heart rate and conduction by the SAS in the heart. T-type Ca2+ channel can be a target for heart disease treatments that aim to slow down the heart rate ABSTRACT: Cav3.1 (α1G ) T-type Ca2+ channel (TTCC) is expressed in mouse sinoatrial node cells (SANCs) and atrioventricular (AV) nodal cells and contributes to heart rate (HR) genesis and AV conduction. However, its role in HR regulation and AV conduction acceleration by the β-adrenergic system (SAS) is unclear. In the present study, L- (ICa-L ) and T-type (ICa-T ) Ca2+ currents were recorded in SANCs from Cav3.1 transgenic (TG) and knockout (KO), and control mice. ICa-T was absent in KO SANCs but enhanced in TG SANCs. In anaesthetized animals, different doses of isoproterenol (ISO) were infused via the jugular vein and the HR was recorded. The EC50 of the HR response to ISO was lower in TG mice but higher in KO mice, and the maximal percentage of HR increase by ISO was greater in TG mice but less in KO mice. In Langendorff-perfused hearts, ISO increased HR and shortened PR intervals to a greater extent in TG but to a less extent in KO hearts. KO SANCs had significantly slower spontaneous beating rates than control SANCs before and after ISO; TG SANCs had similar basal beating rates as control SANCs probably as a result of decreased ICa-L but a greater response to ISO than control SANCs. ICa-T in SANCs was significantly increased by ISO. ICa-T upregulation by β-adrenergic stimulation contributes to HR and conduction regulation by the SAS. TTCC can be a target for slowing the HR.
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MESH Headings
- Adrenergic Agents/pharmacology
- Animals
- Arrhythmias, Cardiac/drug therapy
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/pathology
- Calcium Channels, T-Type/physiology
- Heart Rate/drug effects
- Heart Rate/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Receptors, Adrenergic, beta/metabolism
- Signal Transduction
- Sinoatrial Node/cytology
- Sinoatrial Node/drug effects
- Sinoatrial Node/metabolism
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Affiliation(s)
- Yingxin Li
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
| | - Xiaoxiao Zhang
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyHubei Provincial Key Laboratory of Molecular ImagineWuhanChina
| | - Chen Zhang
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
| | - Xiaoying Zhang
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
| | - Ying Li
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
- The General Hospital of The PLA Rocket ForceBeijingChina
- Institute of Burn Research, Southwest Hospital, State Key Laboratory of TraumaThird Military Medical UniversityChongqingChina
| | - Zhao Qi
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
| | - Christopher Szeto
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
| | - Mingxin Tang
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
| | - Yizhi Peng
- Institute of Burn Research, Southwest Hospital, State Key Laboratory of TraumaThird Military Medical UniversityChongqingChina
| | - Jeffery D. Molkentin
- Howard Hughes Medical Institute & Cincinnati Children's Hospital Medical CenterCincinnatiOHUSA
| | - Steven R. Houser
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
| | - Mingxing Xie
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyHubei Provincial Key Laboratory of Molecular ImagineWuhanChina
| | - Xiongwen Chen
- Cardiovascular Research Center and Department of PhysiologyTemple University School of Medicine3500 North Broad StreetPhiladelphiaPAUSA
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29
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Dressler FF, Brado J, Odening KE. Electromechanical heterogeneity in the heart : A key to long QT syndrome? Herzschrittmacherther Elektrophysiol 2018; 29:43-47. [PMID: 29234865 DOI: 10.1007/s00399-017-0544-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/24/2017] [Indexed: 06/07/2023]
Abstract
In the healthy heart, physiological heterogeneities in structure and in electrical and mechanical activity are crucial for normal, efficient excitation and pumping. Alterations of heterogeneity have been linked to arrhythmogenesis in various cardiac disorders such as long QT syndrome (LQTS). This inherited arrhythmia disorder is caused by mutations in different ion channel genes and is characterized by (heterogeneously) prolonged cardiac repolarization and increased risk for ventricular tachycardia, syncope and sudden cardiac death. Cardiac electrical and mechanical function are not independent of each other but interact in a bidirectional manner by electromechanical and mechano-electrical coupling. Therefore, changes in either process will affect the other. Recent experimental and clinical evidence suggests that LQTS, which is primarily considered an "electrical" disorder, also exhibits features of disturbed mechanical function and heterogeneity, which in turn appears to correlate with the risk of arrhythmia in the individual patient. In this review, we give a short overview of the current knowledge about physiological and pathological, long QT-related electrical and mechanical heterogeneity in the heart. Also, their respective roles for future risk prediction approaches in LQTS are discussed.
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Affiliation(s)
- F F Dressler
- Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - J Brado
- Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Medizinische Klinik und Poliklinik I, Klinikum der Universität München, Munich, Germany
| | - K E Odening
- Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany.
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.
- Institute for Experimental Cardiovascular Medicine, Heart Center, University of Freiburg, Freiburg, Germany.
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30
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Kozasa Y, Nakashima N, Ito M, Ishikawa T, Kimoto H, Ushijima K, Makita N, Takano M. HCN4 pacemaker channels attenuate the parasympathetic response and stabilize the spontaneous firing of the sinoatrial node. J Physiol 2018; 596:809-825. [PMID: 29315578 PMCID: PMC5830425 DOI: 10.1113/jp275303] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 01/02/2018] [Indexed: 01/01/2023] Open
Abstract
Key points The contribution of HCN4 pacemaker channels in the autonomic regulation of the sino‐atrial node (SAN) has been a matter of debate. The transgenic overexpression of HCN4 did not induce tachycardia, but reduced heart rate variability, while the conditional knockdown of HCN4 gave rise to sinus arrhythmia. The response of the SAN to β‐adrenergic stimulation was not affected by overexpression or knockdown of HCN4 channels. When HCN4 channels were knocked down, the parasympathetic response examined by cervical vagus nerve stimulation (CVNS) was enhanced; the CVNS induced complete sinus pause. The overexpression of HCN4 attenuated bradycardia induced by CVNS only during β‐adrenergic stimulation. We concluded that HCN4 pacemaker channels stabilize the spontaneous firing by attenuating the parasympathetic response of the SAN.
Abstract The heart rate is dynamically controlled by the sympathetic and parasympathetic nervous systems that regulate the sinoatrial node (SAN). HCN4 pacemaker channels are the well‐known causative molecule of congenital sick sinus syndrome. Although HCN4 channels are activated by cAMP, the sympathetic response of the SAN was preserved in patients carrying loss‐of‐function mutations of the HCN4 gene. In order to clarify the contribution of HCN4 channels in the autonomic regulation of the SAN, we developed novel gain‐of‐function mutant mice in which the expression level of HCN4 channels could be reversibly changed from zero to ∼3 times that in wild‐type mice, using tetracycline transactivator and the tetracycline responsive element. We recorded telemetric ECGs in freely moving conscious mice and analysed the heart rate variability. We also evaluated the response of the SAN to cervical vagus nerve stimulation (CVNS). The conditional overexpression of HCN4 did not induce tachycardia, but reduced heart rate variability. The HCN4 overexpression also attenuated bradycardia induced by the CVNS only during the β‐adrenergic stimulation. In contrast, the knockdown of HCN4 gave rise to sinus arrhythmia, and enhanced the parasympathetic response; complete sinus pause was induced by the CVNS. In vitro, we compared the effects of acetylcholine on the spontaneous action potentials of single pacemaker cells, and found that similar phenotypic changes were induced by genetic manipulation of HCN4 expression both in the presence and absence of β‐adrenergic stimulation. Our study suggests that HCN4 channels attenuate the vagal response of the SAN, and thereby stabilize the spontaneous firing of the SAN. The contribution of HCN4 pacemaker channels in the autonomic regulation of the sino‐atrial node (SAN) has been a matter of debate. The transgenic overexpression of HCN4 did not induce tachycardia, but reduced heart rate variability, while the conditional knockdown of HCN4 gave rise to sinus arrhythmia. The response of the SAN to β‐adrenergic stimulation was not affected by overexpression or knockdown of HCN4 channels. When HCN4 channels were knocked down, the parasympathetic response examined by cervical vagus nerve stimulation (CVNS) was enhanced; the CVNS induced complete sinus pause. The overexpression of HCN4 attenuated bradycardia induced by CVNS only during β‐adrenergic stimulation. We concluded that HCN4 pacemaker channels stabilize the spontaneous firing by attenuating the parasympathetic response of the SAN.
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Affiliation(s)
- Yuko Kozasa
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan.,Department of Anesthesiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan
| | - Noriyuki Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan
| | - Masayuki Ito
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Taisuke Ishikawa
- Department of Molecular Physiology, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan
| | - Hiroki Kimoto
- Department of Molecular Physiology, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan
| | - Kazuo Ushijima
- Department of Anesthesiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan
| | - Naomasa Makita
- Department of Molecular Physiology, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan
| | - Makoto Takano
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, 830-0011, Japan
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Ng GA. Feasibility of selection of antiarrhythmic drug treatment on the basis of arrhythmogenic mechanism — Relevance of electrical restitution, wavebreak and rotors. Pharmacol Ther 2017; 176:1-12. [DOI: 10.1016/j.pharmthera.2016.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Osadchii OE. Role of abnormal repolarization in the mechanism of cardiac arrhythmia. Acta Physiol (Oxf) 2017; 220 Suppl 712:1-71. [PMID: 28707396 DOI: 10.1111/apha.12902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In cardiac patients, life-threatening tachyarrhythmia is often precipitated by abnormal changes in ventricular repolarization and refractoriness. Repolarization abnormalities typically evolve as a consequence of impaired function of outward K+ currents in cardiac myocytes, which may be caused by genetic defects or result from various acquired pathophysiological conditions, including electrical remodelling in cardiac disease, ion channel modulation by clinically used pharmacological agents, and systemic electrolyte disorders seen in heart failure, such as hypokalaemia. Cardiac electrical instability attributed to abnormal repolarization relies on the complex interplay between a provocative arrhythmic trigger and vulnerable arrhythmic substrate, with a central role played by the excessive prolongation of ventricular action potential duration, impaired intracellular Ca2+ handling, and slowed impulse conduction. This review outlines the electrical activity of ventricular myocytes in normal conditions and cardiac disease, describes classical electrophysiological mechanisms of cardiac arrhythmia, and provides an update on repolarization-related surrogates currently used to assess arrhythmic propensity, including spatial dispersion of repolarization, activation-repolarization coupling, electrical restitution, TRIaD (triangulation, reverse use dependence, instability, and dispersion), and the electromechanical window. This is followed by a discussion of the mechanisms that account for the dependence of arrhythmic vulnerability on the location of the ventricular pacing site. Finally, the review clarifies the electrophysiological basis for cardiac arrhythmia produced by hypokalaemia, and gives insight into the clinical importance and pathophysiology of drug-induced arrhythmia, with particular focus on class Ia (quinidine, procainamide) and Ic (flecainide) Na+ channel blockers, and class III antiarrhythmic agents that block the delayed rectifier K+ channel (dofetilide).
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Affiliation(s)
- O. E. Osadchii
- Department of Health Science and Technology; University of Aalborg; Aalborg Denmark
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Dressler FF, Bodi I, Menza M, Moss R, Bugger H, Bode C, Behrends JC, Seemann G, Odening KE. Interregional electro-mechanical heterogeneity in the rabbit myocardium. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:344-355. [PMID: 28655649 DOI: 10.1016/j.pbiomolbio.2017.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 12/28/2022]
Abstract
BACKGROUND Increased electrical heterogeneity has been causatively linked to arrhythmic disorders, yet the knowledge about physiological heterogeneity remains incomplete. This study investigates regional electro-mechanical heterogeneities in rabbits, one of the key animal models for arrhythmic disorders. METHODS AND FINDINGS 7 wild-type rabbits were examined by phase-contrast magnetic resonance imaging in vivo to assess cardiac wall movement velocities. Using a novel data-processing algorithm regional contraction-like profiles were calculated. Contraction started earlier and was longer in left ventricular (LV) apex than base. Patch clamp recordings showed longer action potentials (AP) in LV apex compared to the base of LV, septum, and right ventricle. Western blots of cardiac ion channels and calcium handling proteins showed lower expression of Cav1.2, KvLQT1, Kv1.4, NCX and Phospholamban in LV apex vs. base. A single-cell in silico model integrating the quantitative regional differences in ion channels reproduced a longer contraction and longer AP in apex vs. base. CONCLUSIONS Apico-basal electro-mechanical heterogeneity is physiologically present in the healthy rabbit heart. An apico-basal electro-mechanical gradient exists with longer APD and contraction duration in the apex and associated regionally heterogeneous expression of five key proteins. This pattern of apical mechanical dominance probably serves to increase pumping efficiency.
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Affiliation(s)
- Franz F Dressler
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany
| | - Ilona Bodi
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany
| | - Marius Menza
- Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Department of Medical Physics, Medical Center - University of Freiburg, Breisacher Straße 60a, 79106 Freiburg, Germany
| | - Robin Moss
- Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76128 Karlsruhe, Germany; Institute for Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Center - University of Freiburg, Elsaesserstrasse 2q, 79110 Freiburg, Germany
| | - Heiko Bugger
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany
| | - Christoph Bode
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany
| | - Jan C Behrends
- Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Department of Physiology, Laboratory for Membrane Physiology and -Technology, University of Freiburg, Hermann-Herder-Strasse 7, 79104 Freiburg, Germany
| | - Gunnar Seemann
- Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76128 Karlsruhe, Germany; Institute for Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Center - University of Freiburg, Elsaesserstrasse 2q, 79110 Freiburg, Germany
| | - Katja E Odening
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Breisacher Strasse 153, 79110 Freiburg, Germany; Institute for Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Center - University of Freiburg, Elsaesserstrasse 2q, 79110 Freiburg, Germany.
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Finlay M, Harmer SC, Tinker A. The control of cardiac ventricular excitability by autonomic pathways. Pharmacol Ther 2017; 174:97-111. [PMID: 28223225 DOI: 10.1016/j.pharmthera.2017.02.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Central to the genesis of ventricular cardiac arrhythmia are variations in determinants of excitability. These involve individual ionic channels and transporters in cardiac myocytes but also tissue factors such as variable conduction of the excitation wave, fibrosis and source-sink mismatch. It is also known that in certain diseases and particularly the channelopathies critical events occur with specific stressors. For example, in hereditary long QT syndrome due to mutations in KCNQ1 arrhythmic episodes are provoked by exercise and in particular swimming. Thus not only is the static substrate important but also how this is modified by dynamic signalling events associated with common physiological responses. In this review, we examine the regulation of ventricular excitability by signalling pathways from a cellular and tissue perspective in an effort to identify key processes, effectors and potential therapeutic approaches. We specifically focus on the autonomic nervous system and related signalling pathways.
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Affiliation(s)
- Malcolm Finlay
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Charterhouse Square, London EC1M6BQ, UK
| | - Stephen C Harmer
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Charterhouse Square, London EC1M6BQ, UK
| | - Andrew Tinker
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Charterhouse Square, London EC1M6BQ, UK.
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Kalla M, Herring N, Paterson DJ. Cardiac sympatho-vagal balance and ventricular arrhythmia. Auton Neurosci 2016; 199:29-37. [PMID: 27590099 PMCID: PMC5334443 DOI: 10.1016/j.autneu.2016.08.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 12/11/2022]
Abstract
A hallmark of cardiovascular disease is cardiac autonomic dysregulation. The phenotype of impaired parasympathetic responsiveness and sympathetic hyperactivity in experimental animal models is also well documented in large scale human studies in the setting of heart failure and myocardial infarction, and is predictive of morbidity and mortality. Despite advances in emergency revascularisation strategies for myocardial infarction, device therapy for heart failure and secondary prevention pharmacotherapies, mortality from malignant ventricular arrhythmia remains high. Patients at highest risk or those with haemodynamically significant ventricular arrhythmia can be treated with catheter ablation and implantable cardioverter defibrillators, but the morbidity and reduction in quality of life due to the burden of ventricular arrhythmia and shock therapy persists. Therefore, future therapies must aim to target the underlying pathophysiology that contributes to the generation of ventricular arrhythmia. This review explores recent advances in mechanistic research in both limbs of the autonomic nervous system and potential avenues for translation into clinical therapy. In addition, we also discuss the relationship of these findings in the context of the reported efficacy of current neuromodulatory strategies in the management of ventricular arrhythmia. We review advances in mechanistic research in the cardiac autonomic nervous system. This is discussed in relation to neuromodulatory therapy for ventricular arrhythmia. Neuromodulation therapies can influence both neurotransmitters and co-transmitters. This may therefore improve on conventional medical treatment.
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Affiliation(s)
| | - Neil Herring
- Corresponding author at: Burdon Sanderson Cardiac Science Centre, Dept. of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, OX13PT, UK.Burdon Sanderson Cardiac Science CentreDept. of Physiology, Anatomy and GeneticsUniversity of OxfordParks RoadOX13PTUK
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Ng GA. Neuro-cardiac interaction in malignant ventricular arrhythmia and sudden cardiac death. Auton Neurosci 2016; 199:66-79. [DOI: 10.1016/j.autneu.2016.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 07/02/2016] [Accepted: 07/04/2016] [Indexed: 12/30/2022]
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Gardner RT, Ripplinger CM, Myles RC, Habecker BA. Molecular Mechanisms of Sympathetic Remodeling and Arrhythmias. Circ Arrhythm Electrophysiol 2016; 9:e001359. [PMID: 26810594 DOI: 10.1161/circep.115.001359] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Ryan T Gardner
- From the Department of Physiology and Pharmacology and Knight Cardiovascular Institute, Oregon Health and Science University, Portland (R.T.G., B.A.H.); Department of Pharmacology, School of Medicine, University of California, Davis (C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.)
| | - Crystal M Ripplinger
- From the Department of Physiology and Pharmacology and Knight Cardiovascular Institute, Oregon Health and Science University, Portland (R.T.G., B.A.H.); Department of Pharmacology, School of Medicine, University of California, Davis (C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.)
| | - Rachel C Myles
- From the Department of Physiology and Pharmacology and Knight Cardiovascular Institute, Oregon Health and Science University, Portland (R.T.G., B.A.H.); Department of Pharmacology, School of Medicine, University of California, Davis (C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.)
| | - Beth A Habecker
- From the Department of Physiology and Pharmacology and Knight Cardiovascular Institute, Oregon Health and Science University, Portland (R.T.G., B.A.H.); Department of Pharmacology, School of Medicine, University of California, Davis (C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.).
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Technical advances in studying cardiac electrophysiology - Role of rabbit models. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:97-109. [PMID: 27210306 DOI: 10.1016/j.pbiomolbio.2016.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 05/01/2016] [Indexed: 12/15/2022]
Abstract
Cardiovascular research has made a major contribution to an unprecedented 10 year increase in life expectancy during the last 50 years: most of this increase due to a decline in mortality from heart disease and stroke. The majority of the basic cardiovascular science discoveries, which have led to this impressive extension of human life, came from investigations conducted in various small and large animal models, ranging from mouse to pig. The small animal models are currently popular because they are amenable to genetic engineering and are relatively inexpensive. The large animal models are favored at the translational stage of the investigation, as they are anatomically and physiologically more proximal to humans, and can be implanted with various devices; however, they are expensive and less amenable to genetic manipulations. With the advent of CRISPR genetic engineering technology and the advances in implantable bioelectronics, the large animal models will continue to advance. The rabbit model is particularly poised to become one of the most popular among the animal models that recapitulate human heart diseases. Here we review an array of the rabbit models of atrial and ventricular arrhythmias, as well as a range of the imaging and device technologies enabling these investigations.
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Ripplinger CM, Noujaim SF, Linz D. The nervous heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 120:199-209. [PMID: 26780507 DOI: 10.1016/j.pbiomolbio.2015.12.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/29/2015] [Accepted: 12/31/2015] [Indexed: 12/23/2022]
Abstract
Many cardiac electrophysiological abnormalities are accompanied by autonomic nervous system dysfunction. Here, we review mechanisms by which the cardiac nervous system controls normal and abnormal excitability and may contribute to atrial and ventricular tachyarrhythmias. Moreover, we explore the potential antiarrhythmic and/or arrhythmogenic effects of modulating the autonomic nervous system by several strategies, including ganglionated plexi ablation, vagal and spinal cord stimulations, and renal sympathetic denervation as therapies for atrial and ventricular arrhythmias.
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Affiliation(s)
- Crystal M Ripplinger
- Department of Pharmacology, University of California Davis, 451 Health Sciences Drive, Davis, CA 95616, USA.
| | - Sami F Noujaim
- Molecular Pharmacology and Physiology, University of South Florida, 12901 Bruce B Downs Blvd, Tampa, FL 33612, USA.
| | - Dominik Linz
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Saar, Germany.
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Perotti LE, Krishnamoorthi S, Borgstrom NP, Ennis DB, Klug WS. Regional segmentation of ventricular models to achieve repolarization dispersion in cardiac electrophysiology modeling. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2015; 31:10.1002/cnm.2718. [PMID: 25845576 PMCID: PMC4519348 DOI: 10.1002/cnm.2718] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 03/01/2015] [Accepted: 03/31/2015] [Indexed: 05/08/2023]
Abstract
The electrocardiogram (ECG) is one of the most significant outputs of a computational model of cardiac electrophysiology because it relates the numerical results to clinical data and is a universal tool for diagnosing heart diseases. One key features of the ECG is the T-wave, which is caused by longitudinal and transmural heterogeneity of the action potential duration (APD). Thus, in order to model a correct wave of repolarization, different cell properties resulting in different APDs must be assigned across the ventricular wall and longitudinally from apex to base. To achieve this requirement, a regional parametrization of the heart is necessary. We propose a robust approach to obtain the transmural and longitudinal segmentation in a general heart geometry without relying on ad hoc procedures. Our approach is based on auxiliary harmonic lifting analyses, already used in the literature to generate myocardial fiber orientations. Specifically, the solution of a sequence of Laplace boundary value problems allows parametrically controlled segmentation of both heart ventricles. The flexibility and simplicity of the proposed method is demonstrated through several representative examples, varying the locations and extents of the epicardial, midwall, and endocardial layers. Effects of the control parameters on the T-wave morphology are illustrated via computed ECGs.
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Affiliation(s)
- L. E. Perotti
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California, United States of America
- Department of Bioengineering, University of California, Los Angeles, California, United States of America
- Department of Radiological Sciences, University of California, Los Angeles, California, United States of America
| | - S. Krishnamoorthi
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California, United States of America
| | - N. P. Borgstrom
- Department of Bioengineering, University of California, Los Angeles, California, United States of America
| | - D. B. Ennis
- Department of Bioengineering, University of California, Los Angeles, California, United States of America
- Department of Radiological Sciences, University of California, Los Angeles, California, United States of America
| | - W. S. Klug
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California, United States of America
- Correspondence to: Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, United States of America.
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Winter J, Lee AW, Niederer S, Shattock MJ. Vagal modulation of dispersion of repolarisation in the rabbit heart. J Mol Cell Cardiol 2015; 85:89-101. [DOI: 10.1016/j.yjmcc.2015.05.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 05/08/2015] [Accepted: 05/13/2015] [Indexed: 10/23/2022]
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Kuroda R, Shintani-Ishida K, Unuma K, Yoshida KI. Immobilization Stress With α2-Adrenergic Stimulation Induces Regional and Transient Reduction of Cardiac Contraction Through Gi Coupling in Rats. Int Heart J 2015; 56:537-43. [DOI: 10.1536/ihj.15-034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ryohei Kuroda
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo
| | - Kaori Shintani-Ishida
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo
| | - Kana Unuma
- Section of Forensic Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Ken-ichi Yoshida
- Department of Forensic Medicine, Graduate School of Medicine, The University of Tokyo
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Bub G, Burton RAB. Macro-micro imaging of cardiac-neural circuits in co-cultures from normal and diseased hearts. J Physiol 2014; 593:3047-53. [PMID: 25398529 DOI: 10.1113/jphysiol.2014.285460] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 10/22/2014] [Indexed: 12/16/2022] Open
Abstract
The autonomic nervous system plays an important role in the modulation of normal cardiac rhythm, but is also implicated in modulating the heart's susceptibility to re-entrant ventricular and atrial arrhythmias. The mechanisms by which the autonomic nervous system is pro-arrhythmic or anti-arrhythmic is multifaceted and varies for different types of arrhythmia and their cardiac substrates. Despite decades of research in this area, fundamental questions related to how neuron density and spatial organization modulate cardiac wave dynamics remain unanswered. These questions may be ill-posed in intact tissues where the activity of individual cells is often experimentally inaccessible. Development of simplified biological models that would allow us to better understand the influence of neural activation on cardiac activity can be beneficial. This Symposium Review summarizes the development of in vitro cardiomyocyte cell culture models of re-entrant activity, as well as challenges associated with extending these models to include the effects of neural activation.
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Affiliation(s)
- Gil Bub
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Rebecca-Ann B Burton
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
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Krishnamoorthi S, Perotti LE, Borgstrom NP, Ajijola OA, Frid A, Ponnaluri AV, Weiss JN, Qu Z, Klug WS, Ennis DB, Garfinkel A. Simulation Methods and Validation Criteria for Modeling Cardiac Ventricular Electrophysiology. PLoS One 2014; 9:e114494. [PMID: 25493967 PMCID: PMC4262432 DOI: 10.1371/journal.pone.0114494] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/07/2014] [Indexed: 01/24/2023] Open
Abstract
We describe a sequence of methods to produce a partial differential equation model of the electrical activation of the ventricles. In our framework, we incorporate the anatomy and cardiac microstructure obtained from magnetic resonance imaging and diffusion tensor imaging of a New Zealand White rabbit, the Purkinje structure and the Purkinje-muscle junctions, and an electrophysiologically accurate model of the ventricular myocytes and tissue, which includes transmural and apex-to-base gradients of action potential characteristics. We solve the electrophysiology governing equations using the finite element method and compute both a 6-lead precordial electrocardiogram (ECG) and the activation wavefronts over time. We are particularly concerned with the validation of the various methods used in our model and, in this regard, propose a series of validation criteria that we consider essential. These include producing a physiologically accurate ECG, a correct ventricular activation sequence, and the inducibility of ventricular fibrillation. Among other components, we conclude that a Purkinje geometry with a high density of Purkinje muscle junctions covering the right and left ventricular endocardial surfaces as well as transmural and apex-to-base gradients in action potential characteristics are necessary to produce ECGs and time activation plots that agree with physiological observations.
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Affiliation(s)
- Shankarjee Krishnamoorthi
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Luigi E. Perotti
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Nils P. Borgstrom
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Olujimi A. Ajijola
- Department of Medicine (Cardiology), University of California Los Angeles, Los Angeles, California, United States of America
| | - Anna Frid
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Aditya V. Ponnaluri
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - James N. Weiss
- Department of Medicine (Cardiology), University of California Los Angeles, Los Angeles, California, United States of America
| | - Zhilin Qu
- Department of Medicine (Cardiology), University of California Los Angeles, Los Angeles, California, United States of America
| | - William S. Klug
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Daniel B. Ennis
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, United States of America
| | - Alan Garfinkel
- Department of Medicine (Cardiology), University of California Los Angeles, Los Angeles, California, United States of America
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Yamakawa K, So EL, Rajendran PS, Hoang JD, Makkar N, Mahajan A, Shivkumar K, Vaseghi M. Electrophysiological effects of right and left vagal nerve stimulation on the ventricular myocardium. Am J Physiol Heart Circ Physiol 2014; 307:H722-31. [PMID: 25015962 DOI: 10.1152/ajpheart.00279.2014] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Vagal nerve stimulation (VNS) has been proposed as a cardioprotective intervention. However, regional ventricular electrophysiological effects of VNS are not well characterized. The purpose of this study was to evaluate effects of right and left VNS on electrophysiological properties of the ventricles and hemodynamic parameters. In Yorkshire pigs, a 56-electrode sock was used for epicardial (n = 12) activation recovery interval (ARI) recordings and a 64-electrode catheter for endocardial (n = 9) ARI recordings at baseline and during VNS. Hemodynamic recordings were obtained using a conductance catheter. Right and left VNS decreased heart rate (84 ± 5 to 71 ± 5 beats/min and 84 ± 4 to 73 ± 5 beats/min), left ventricular pressure (89 ± 9 to 77 ± 9 mmHg and 91 ± 9 to 83 ± 9 mmHg), and dP/dtmax (1,660 ± 154 to 1,490 ± 160 mmHg/s and 1,595 ± 155 to 1,416 ± 134 mmHg/s) and prolonged ARI (327 ± 18 to 350 ± 23 ms and 327 ± 16 to 347 ± 21 ms, P < 0.05 vs. baseline for all parameters and P = not significant for right VNS vs. left VNS). No anterior-posterior-lateral regional differences in the prolongation of ARI during right or left VNS were found. However, endocardial ARI prolonged more than epicardial ARI, and apical ARI prolonged more than basal ARI during both right and left VNS. Changes in dP/dtmax showed the strongest correlation with ventricular ARI effects (R(2) = 0.81, P < 0.0001) than either heart rate (R(2) = 0.58, P < 0.01) or left ventricular pressure (R(2) = 0.52, P < 0.05). Therefore, right and left VNS have similar effects on ventricular ARI, in contrast to sympathetic stimulation, which shows regional differences. The decrease in inotropy correlates best with ventricular electrophysiological effects.
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Affiliation(s)
- Kentaro Yamakawa
- Department of Anesthesiology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Eileen L So
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California
| | - Pradeep S Rajendran
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Program, David Geffen School of Medicine at UCLA, Los Angeles, California; and
| | - Jonathan D Hoang
- Department of Anesthesiology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Nupur Makkar
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California
| | - Aman Mahajan
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Program, David Geffen School of Medicine at UCLA, Los Angeles, California; and Department of Anesthesiology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Kalyanam Shivkumar
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Program, David Geffen School of Medicine at UCLA, Los Angeles, California; and
| | - Marmar Vaseghi
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Program, David Geffen School of Medicine at UCLA, Los Angeles, California; and
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Abstract
Sexual dimorphism is a well-established phenomenon, but its degree varies tremendously among species. Since the early days of Einthoven's development of the three-lead galvanometer ECG, we have known there are marked differences in QT intervals of men and women. It required over a century to appreciate the profound implications of sex-based electrophysiological differences in QT interval on the panoply of sex differences with respect to arrhythmia risk, drug sensitivity, and treatment modalities. Little is known about the fundamental mechanism responsible for sex differences in electrical substrate of the human heart, in large part due to the lack of tissue availability. Animal models are an important research tool, but species differences in the sexual dimorphism of the QT interval, the ionic currents underlying the cardiac repolarization, and effects of sex steroids make it difficult to interpolate animal to human sex differences. In addition, in some species, different strains of the same animal model yield conflicting data. Each model has its strengths, such as ease of genetic manipulation in mice or size in dogs. However, many animals do not reproduce the sexual dimorphism of QT seen in humans. To match sex linked prolongation of QT interval and arrhythmogenic phenotype, the current data suggest that the rabbit may be best suited to provide insight into sex differences in humans. In the future, emerging technologies such as induced pluripotent stem cell derived cardiac myocyte systems may offer the opportunity to study sex differences in a controlled hormonal situation in the context of a sex specific human model system.
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Affiliation(s)
- Guy Salama
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania; University of Pittsburgh Medical Center Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Glenna C L Bett
- Center for Cellular and Systems Electrophysiology, University at Buffalo, State University of New York, Buffalo, New York; Department of Obstetrics and Gynecology, University at Buffalo, State University of New York, Buffalo, New York; and Department of Physiology and Biophysics, University at Buffalo, State University of New York, Buffalo, New York
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Mechanisms underlying the autonomic modulation of ventricular fibrillation initiation--tentative prophylactic properties of vagus nerve stimulation on malignant arrhythmias in heart failure. Heart Fail Rev 2014; 18:389-408. [PMID: 22678767 PMCID: PMC3677978 DOI: 10.1007/s10741-012-9314-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Classical physiology teaches that vagal post-ganglionic nerves modulate the heart via acetylcholine acting at muscarinic receptors, whilst it is accepted that vagus nerve stimulation (VNS) slows heart rate, atrioventricular conduction and decreases atrial contraction; there is continued controversy as to whether the vagus has any significant direct effect on ventricular performance. Despite this, there is a significant body of evidence from experimental and clinical studies, demonstrating that the vagus nerve has an anti-arrhythmic action, protecting against induced and spontaneously occurring ventricular arrhythmias. Over 100 years ago Einbrodt first demonstrated that direct cervical VNS significantly increased the threshold for experimentally induced ventricular fibrillation. A large body of evidence has subsequently been collected supporting the existence of an anti-arrhythmic effect of the vagus on the ventricle. The development of prognostic indicators of heart rate variability and baroreceptor reflex sensitivity—measures of parasympathetic tone and reflex activation respectively—and the more recent interest in chronic VNS therapy are a direct consequence of the earlier experimental studies. Despite this, mechanisms underlying the anti-arrhythmic actions of the vagus nerve have not been fully characterised and are not well understood. This review summarises historical and recently published data to highlight the importance of this powerful endogenous protective phenomenon.
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Cardiac contractility modulation increases action potential duration dispersion and decreases ventricular fibrillation threshold via β1-adrenoceptor activation in the crystalloid perfused normal rabbit heart. Int J Cardiol 2014; 172:144-54. [PMID: 24456882 PMCID: PMC3978661 DOI: 10.1016/j.ijcard.2013.12.184] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 06/19/2013] [Accepted: 12/31/2013] [Indexed: 11/21/2022]
Abstract
BACKGROUND/OBJECTIVES Cardiac contractility modulation (CCM) is a new treatment being developed for heart failure (HF) involving application of electrical current during the absolute refractory period. We have previously shown that CCM increases ventricular force through β1-adrenoceptor activation in the whole heart, a potential pro-arrhythmic mechanism. This study aimed to investigate the effect of CCM on ventricular fibrillation susceptibility. METHODS Experiments were conducted in isolated New Zealand white rabbit hearts (2.0-2.5 kg, n=25). The effects of CCM (± 20 mA, 10 ms phase duration) on the left ventricular basal and apical monophasic action potential duration (MAPD) were assessed during constant pacing (200 bpm). Ventricular fibrillation threshold (VFT) was defined as the minimum current required to induce sustained VF with rapid pacing (30 × 30 ms). Protocols were repeated during perfusion of the β1-adrenoceptor antagonist metoprolol (1.8 μM). In separate hearts, the dynamic and spatial electrophysiological effects of CCM were assessed using optical mapping with di-4-ANEPPS. RESULTS CCM significantly shortened MAPD close to the stimulation site (Basal: 102 ± 5 [CCM] vs. 131 ± 6 [Control] ms, P<0.001). VFT was reduced during CCM (2.6 ± 0.6 [CCM] vs. 6.1 ± 0.8 [Control] mA, P<0.01) and was correlated (r(2)=0.40, P<0.01) with increased MAPD dispersion (26 ± 4 [CCM] vs. 5 ± 1 [Control] ms, P<0.01) (n=8). Optical mapping revealed greater spread of CCM induced MAPD shortening during basal vs. apical stimulation. CCM effects were abolished by metoprolol and exogenous acetylcholine. No evidence for direct electrotonic modulation of APD was found, with APD adaptation occurring secondary to adrenergic stimulation. CONCLUSIONS CCM decreases VFT in a manner associated with increased MAPD dispersion in the crystalloid perfused normal rabbit heart.
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Abstract
NEW FINDINGS What is the topic of this review? This article addresses the relationship between vagus nerve activity and malignant ventricular arrhythmias. It focuses on the clinical association of an impaired vagal tone in cardiac disease states with high mortality from sudden cardiac death and the potential underlying mechanisms. What advances does it highlight? The article summarizes the mounting evidence that vagal innervation in the cardiac ventricle plays a key direct role in the prevention of the initiation of ventricular fibrillation. Data are presented on the role that nitric oxide plays in mediating the effects of vagal protection against ventricular fibrillation, supporting the notion that a separate non-muscarinic, nitrergic population of vagal neurons is responsible for this protection. Sudden cardiac death remains a significant unresolved clinical problem, with many of the deaths being due to malignant ventricular arrhythmias. Markers of abnormal autonomic function have been shown to be strong prognostic predictors, highlighting the important relationship between reduced vagal tone and malignant ventricular arrhythmias, such as ventricular fibrillation, in cardiac patients. Exploring the mechanisms underlying the autonomic modulation of ventricular fibrillation, my group has shown that vagus nerve stimulation protects against ventricular fibrillation in the innervated isolated heart preparation. We have provided direct evidence that nitric oxide is released in the ventricle with cervical vagus nerve stimulation and NO mediates the antifibrillatory actions of vagus nerve stimulation in the ventricle. Classical physiology teaches that vagal postganglionic nerves modulate the heart via acetylcholine acting at muscarinic receptors and, dogmatically, that there is little vagal effect in the ventricle, as innervation was believed to be sparse. Mounting evidence from many species now supports the presence of a rich vagal innervation in the ventricle. Data from my group showing that the protective actions of vagus nerve stimulation against ventricular fibrillation and NO release are preserved in the presence of muscarinic block support the notion that a population of nitrergic neurons could be responsible. This potentially exploitable downstream pathway together with the availability of vagus nerve stimulators make it an exciting time to investigate the development of an effective strategy of vagal protection against ventricular fibrillation in the clinical setting.
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Affiliation(s)
- G André Ng
- * Department of Cardiovascular Sciences, Cardiology group, University of Leicester, Clinical Sciences Wing, Glenfield Hospital, Leicester LE3 9QP, UK.
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