1
|
Stoyek MR, Hortells L, Quinn TA. From Mice to Mainframes: Experimental Models for Investigation of the Intracardiac Nervous System. J Cardiovasc Dev Dis 2021; 8:149. [PMID: 34821702 PMCID: PMC8620975 DOI: 10.3390/jcdd8110149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 01/17/2023] Open
Abstract
The intracardiac nervous system (IcNS), sometimes referred to as the "little brain" of the heart, is involved in modulating many aspects of cardiac physiology. In recent years our fundamental understanding of autonomic control of the heart has drastically improved, and the IcNS is increasingly being viewed as a therapeutic target in cardiovascular disease. However, investigations of the physiology and specific roles of intracardiac neurons within the neural circuitry mediating cardiac control has been hampered by an incomplete knowledge of the anatomical organisation of the IcNS. A more thorough understanding of the IcNS is hoped to promote the development of new, highly targeted therapies to modulate IcNS activity in cardiovascular disease. In this paper, we first provide an overview of IcNS anatomy and function derived from experiments in mammals. We then provide descriptions of alternate experimental models for investigation of the IcNS, focusing on a non-mammalian model (zebrafish), neuron-cardiomyocyte co-cultures, and computational models to demonstrate how the similarity of the relevant processes in each model can help to further our understanding of the IcNS in health and disease.
Collapse
Affiliation(s)
- Matthew R. Stoyek
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS 15000, Canada;
| | - Luis Hortells
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg–Bad Krozingen, 79110 Freiburg, Germany;
- Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - T. Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS 15000, Canada;
- School of Biomedical Engineering, Dalhousie University, Halifax, NS 15000, Canada
| |
Collapse
|
2
|
Hanna P, L Ardell J, ShivkumarKalyanam K. Cardiac Neuroanatomy for the Cardiac Electrophysiologist. J Atr Fibrillation 2020; 13:2407. [PMID: 33024507 DOI: 10.4022/jafib.2407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/11/2019] [Accepted: 10/12/2019] [Indexed: 12/22/2022]
Abstract
The cardiac neuraxis is integral to cardiac physiology, and its dysregulation is implicated in cardiovascular disease. Neuromodulatory therapies are being developed that target the cardiac autonomic nervous system (ANS) to treat cardiac pathophysiology. An appreciation of the cardiac neuroanatomy is a prerequisite for development of such targeted therapies. Here, we provide a review of the current understanding of the cardiac ANS. The parasympathetic and sympathetic nervous system are composed of higher order cortical centers, brainstem, spinal cord, intrathoracic extracardiac ganglia and intrinsic cardiac ganglia. A series of interacting feedback loops mediates reflex pathways to exert control over the cardiac conduction system and contractile tissue. Further exploration of this complex regulatory system promises to yield neuroscience-based therapeutics for cardiac disease.
Collapse
Affiliation(s)
- Peter Hanna
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine, UCLA, Los Angeles, CA.,UCLA Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA
| | - Jeffrey L Ardell
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine, UCLA, Los Angeles, CA.,UCLA Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA
| | - Kalyanam ShivkumarKalyanam
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine, UCLA, Los Angeles, CA.,UCLA Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA
| |
Collapse
|
3
|
Abstract
PURPOSE OF REVIEW This review aims to describe the latest advances in autonomic neuromodulation approaches to treating cardiac arrhythmias, with a focus on ventricular arrhythmias. RECENT FINDINGS The increasing understanding of neuronal remodeling in cardiac diseases has led to the development and improvement of novel neuromodulation therapies targeting multiple levels of the autonomic nervous system. Thoracic epidural anesthesia, spinal cord stimulation, stellate ganglion modulatory therapies, vagal stimulation, renal denervation, and interventions on the intracardiac nervous system have all been studied in preclinical models, with encouraging preliminary clinical data. The autonomic nervous system regulates all the electrical processes of the heart and plays an important role in the pathophysiology of cardiac arrhythmias. Despite recent advances in the clinical application of cardiac neuromodulation, our comprehension of the anatomy and function of the cardiac autonomic nervous system is still limited. Hopefully in the near future, more preclinical data combined with larger clinical trials will lead to further improvements in neuromodulatory treatment for heart rhythm disorders.
Collapse
|
4
|
Incognito AV, Doherty CJ, Nardone M, Lee JB, Notay K, Seed JD, Millar PJ. Evidence for differential control of muscle sympathetic single units during mild sympathoexcitation in young, healthy humans. Am J Physiol Heart Circ Physiol 2019; 316:H13-H23. [DOI: 10.1152/ajpheart.00675.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two subpopulations of muscle sympathetic single units with opposite discharge characteristics have been identified during low-level cardiopulmonary baroreflex loading and unloading in middle-aged adults and patients with heart failure. The present study sought to determine whether similar subpopulations are present in young healthy adults during cardiopulmonary baroreflex unloading ( study 1) and rhythmic handgrip exercise ( study 2). Continuous hemodynamic and multiunit and single unit muscle sympathetic nerve activity (MSNA) data were collected at baseline and during nonhypotensive lower body negative pressure (LBNP; n = 12) and 40% maximal voluntary contraction rhythmic handgrip exercise (RHG; n = 24). Single unit MSNA responses were classified as anticipated or paradoxical based on whether changes were concordant or discordant with the multiunit MSNA response, respectively. LBNP and RHG both increased multiunit MSNA burst frequency (∆5 ± 3 bursts/min, P < 0.001; ∆5 ± 8 bursts/min, P = 0.005), burst amplitude (∆5 ± 7%, P = 0.04; ∆13 ± 14%, P < 0.001), and total MSNA (∆302 ± 191 AU/min, P = 0.001; ∆585 ± 556 AU/min, P < 0.001). During LBNP and RHG, 43 and 64 muscle single units were identified, respectively, which increased spike frequency (∆9 ± 11 spikes/min, P < 0.001; ∆10 ± 19 spikes/min, P < 0.001) and the probability of multiple spike firing (∆10 ± 12%, P < 0.001; ∆11 ± 26%, P = 0.001). During LBNP and RHG, 36 (84%) and 39 (61%) single units possessed anticipated firing responses (∆12 ± 10 spikes/min, P < 0.001; ∆19 ± 19 spikes/min, P < 0.001), whereas 7 (16%) and 25 (39%) single units exhibited paradoxical reductions (∆−3 ± 1 spikes/min, P = 0.003; ∆−4 ± 5 spikes/min, P < 0.001). The observation of divergent subpopulations of muscle sympathetic single units in healthy young humans during two mild sympathoexcitatory stressors supports differential control at the fiber level as a fundamental characteristic of human sympathetic regulation. NEW & NOTEWORTHY The activity of muscle sympathetic single units was recorded during cardiopulmonary baroreceptor unloading and rhythmic handgrip exercise in young healthy humans. During both stressors, the majority of single units (84% and 61%) exhibited anticipated behavior concordant with the integrated muscle sympathetic response, whereas a smaller proportion (16% and 39%) exhibited paradoxical sympathoinhibition. These results support differential control of postganglionic muscle sympathetic fibers as a characteristic of human sympathetic regulation during mild sympathoexcitatory stress. Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/differential-control-of-sympathetic-outflow-in-young-humans/ .
Collapse
Affiliation(s)
- Anthony V. Incognito
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Connor J. Doherty
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Massimo Nardone
- Department of Kinesiology, University of Guelph-Humber, Toronto, Ontario, Canada
| | - Jordan B. Lee
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Karambir Notay
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jeremy D. Seed
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Philip J. Millar
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
- Toronto General Research Institute, Toronto, Ontario, Canada
| |
Collapse
|
5
|
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: 5] [Impact Index Per Article: 0.8] [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.
Collapse
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.
| |
Collapse
|
6
|
Wang T, Miller KE. Characterization of glutamatergic neurons in the rat atrial intrinsic cardiac ganglia that project to the cardiac ventricular wall. Neuroscience 2016; 329:134-50. [PMID: 27167082 PMCID: PMC5922425 DOI: 10.1016/j.neuroscience.2016.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 04/29/2016] [Accepted: 05/03/2016] [Indexed: 12/20/2022]
Abstract
The intrinsic cardiac nervous system modulates cardiac function by acting as an integration site for regulating autonomic efferent cardiac output. This intrinsic system is proposed to be composed of a short cardio-cardiac feedback control loop within the cardiac innervation hierarchy. For example, electrophysiological studies have postulated the presence of sensory neurons in intrinsic cardiac ganglia (ICG) for regional cardiac control. There is still a knowledge gap, however, about the anatomical location and neurochemical phenotype of sensory neurons inside ICG. In the present study, rat ICG neurons were characterized neurochemically with immunohistochemistry using glutamatergic markers: vesicular glutamate transporters 1 and 2 (VGLUT1; VGLUT2), and glutaminase (GLS), the enzyme essential for glutamate production. Glutamatergic neurons (VGLUT1/VGLUT2/GLS) in the ICG that have axons to the ventricles were identified by retrograde tracing of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injected in the ventricular wall. Co-labeling of VGLUT1, VGLUT2, and GLS with the vesicular acetylcholine transporter (VAChT) was used to evaluate the relationship between post-ganglionic autonomic neurons and glutamatergic neurons. Sequential labeling of VGLUT1 and VGLUT2 in adjacent tissue sections was used to evaluate the co-localization of VGLUT1 and VGLUT2 in ICG neurons. Our studies yielded the following results: (1) ICG contain glutamatergic neurons with GLS for glutamate production and VGLUT1 and 2 for transport of glutamate into synaptic vesicles; (2) atrial ICG contain neurons that project to ventricle walls and these neurons are glutamatergic; (3) many glutamatergic ICG neurons also were cholinergic, expressing VAChT; (4) VGLUT1 and VGLUT2 co-localization occurred in ICG neurons with variation of their protein expression level. Investigation of both glutamatergic and cholinergic ICG neurons could help in better understanding the function of the intrinsic cardiac nervous system.
Collapse
Affiliation(s)
- Ting Wang
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, United States
| | - Kenneth E Miller
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, United States.
| |
Collapse
|
7
|
Ardell JL, Andresen MC, Armour JA, Billman GE, Chen PS, Foreman RD, Herring N, O'Leary DS, Sabbah HN, Schultz HD, Sunagawa K, Zucker IH. Translational neurocardiology: preclinical models and cardioneural integrative aspects. J Physiol 2016; 594:3877-909. [PMID: 27098459 DOI: 10.1113/jp271869] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/14/2016] [Indexed: 12/15/2022] Open
Abstract
Neuronal elements distributed throughout the cardiac nervous system, from the level of the insular cortex to the intrinsic cardiac nervous system, are in constant communication with one another to ensure that cardiac output matches the dynamic process of regional blood flow demand. Neural elements in their various 'levels' become differentially recruited in the transduction of sensory inputs arising from the heart, major vessels, other visceral organs and somatic structures to optimize neuronal coordination of regional cardiac function. This White Paper will review the relevant aspects of the structural and functional organization for autonomic control of the heart in normal conditions, how these systems remodel/adapt during cardiac disease, and finally how such knowledge can be leveraged in the evolving realm of autonomic regulation therapy for cardiac therapeutics.
Collapse
Affiliation(s)
- J L Ardell
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - M C Andresen
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
| | - J A Armour
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - G E Billman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - P-S Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R D Foreman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - N Herring
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - D S O'Leary
- Department of Physiology, Wayne State University, Detroit, MI, USA
| | - H N Sabbah
- Department of Medicine, Henry Ford Hospital, Detroit, MI, USA
| | - H D Schultz
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - K Sunagawa
- Department of Cardiovascular Medicine, Kyushu University, Fukuoka, Japan
| | - I H Zucker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| |
Collapse
|
8
|
Silvani A, Calandra-Buonaura G, Dampney RAL, Cortelli P. Brain-heart interactions: physiology and clinical implications. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2015.0181. [PMID: 27044998 DOI: 10.1098/rsta.2015.0181] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/19/2016] [Indexed: 05/03/2023]
Abstract
The brain controls the heart directly through the sympathetic and parasympathetic branches of the autonomic nervous system, which consists of multi-synaptic pathways from myocardial cells back to peripheral ganglionic neurons and further to central preganglionic and premotor neurons. Cardiac function can be profoundly altered by the reflex activation of cardiac autonomic nerves in response to inputs from baro-, chemo-, nasopharyngeal and other receptors as well as by central autonomic commands, including those associated with stress, physical activity, arousal and sleep. In the clinical setting, slowly progressive autonomic failure frequently results from neurodegenerative disorders, whereas autonomic hyperactivity may result from vascular, inflammatory or traumatic lesions of the autonomic nervous system, adverse effects of drugs and chronic neurological disorders. Both acute and chronic manifestations of an imbalanced brain-heart interaction have a negative impact on health. Simple, widely available and reliable cardiovascular markers of the sympathetic tone and of the sympathetic-parasympathetic balance are lacking. A deeper understanding of the connections between autonomic cardiac control and brain dynamics through advanced signal and neuroimage processing may lead to invaluable tools for the early detection and treatment of pathological changes in the brain-heart interaction.
Collapse
Affiliation(s)
| | - Giovanna Calandra-Buonaura
- Autonomic Unit, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy IRCCS, Institute of Neurological Sciences of Bologna, Bellaria University Hospital, Block G, Via Altura 3, 40139 Bologna, Italy
| | - Roger A L Dampney
- School of Medical Sciences (Physiology) and Bosch Institute for Biomedical Research, University of Sydney, Sidney, New South Wales, Australia
| | - Pietro Cortelli
- Autonomic Unit, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy IRCCS, Institute of Neurological Sciences of Bologna, Bellaria University Hospital, Block G, Via Altura 3, 40139 Bologna, Italy
| |
Collapse
|
9
|
Beaumont E, Wright GL, Southerland EM, Li Y, Chui R, KenKnight BH, Armour JA, Ardell JL. Vagus nerve stimulation mitigates intrinsic cardiac neuronal remodeling and cardiac hypertrophy induced by chronic pressure overload in guinea pig. Am J Physiol Heart Circ Physiol 2016; 310:H1349-59. [PMID: 26993230 DOI: 10.1152/ajpheart.00939.2015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/17/2016] [Indexed: 02/06/2023]
Abstract
Our objective was to determine whether chronic vagus nerve stimulation (VNS) mitigates pressure overload (PO)-induced remodeling of the cardioneural interface. Guinea pigs (n = 48) were randomized to right or left cervical vagus (RCV or LCV) implant. After 2 wk, chronic left ventricular PO was induced by partial (15-20%) aortic constriction. Of the 31 animals surviving PO induction, 10 were randomized to RCV VNS, 9 to LCV VNS, and 12 to sham VNS. VNS was delivered at 20 Hz and 1.14 ± 0.03 mA at a 22% duty cycle. VNS commenced 10 days after PO induction and was maintained for 40 days. Time-matched controls (n = 9) were evaluated concurrently. Echocardiograms were obtained before and 50 days after PO. At termination, intracellular current-clamp recordings of intrinsic cardiac (IC) neurons were studied in vitro to determine effects of therapy on soma characteristics. Ventricular cardiomyocyte sizes were assessed with histology along with immunoblot analysis of selected proteins in myocardial tissue extracts. In sham-treated animals, PO increased cardiac output (34%, P < 0.004), as well as systolic (114%, P < 0.04) and diastolic (49%, P < 0.002) left ventricular volumes, a hemodynamic response prevented by VNS. PO-induced enhancements of IC synaptic efficacy and muscarinic sensitivity of IC neurons were mitigated by chronic VNS. Increased myocyte size, which doubled in PO (P < 0.05), was mitigated by RCV. PO hypertrophic myocardium displayed decreased glycogen synthase (GS) protein levels and accumulation of the phosphorylated (inactive) form of GS. These PO-induced changes in GS were moderated by left VNS. Chronic VNS targets IC neurons accompanying PO to obtund associated adverse cardiomyocyte remodeling.
Collapse
Affiliation(s)
- Eric Beaumont
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Gary L Wright
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Elizabeth M Southerland
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Ying Li
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Ray Chui
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, California
| | | | - J Andrew Armour
- UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los Angeles, California
| | - Jeffrey L Ardell
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los Angeles, California
| |
Collapse
|
10
|
Winter J, Tanko AS, Brack KE, Coote JH, Ng GA. Differential cardiac responses to unilateral sympathetic nerve stimulation in the isolated innervated rabbit heart. Auton Neurosci 2012; 166:4-14. [DOI: 10.1016/j.autneu.2011.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 11/30/2022]
|
11
|
Bonnemeier H, Demming T, Weidtmann B, Ortak J, Burgdorf C, Reppel M, Mäuser W, Rosenberg M, Frey N. Differential heart rate dynamics in transient left ventricular apical and midventricular ballooning. Heart Rhythm 2010; 7:1825-32. [PMID: 20817016 DOI: 10.1016/j.hrthm.2010.08.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 08/30/2010] [Indexed: 01/25/2023]
Abstract
BACKGROUND The aim of the present study was to assess potential differences in cardiac autonomic nervous modulation in patients with transient left ventricular apical ballooning syndrome (AB) and the midventricular variant (MB) of this syndrome. OBJECTIVE We hypothesized that differences in regional distribution of cardiac autonomic innervation in AB and MB may induce alterations in autonomic modulation, and we tested this assumption by using a combination of traditional and novel nonlinear parameters of heart rate variability (HRV). METHODS In a prospective single-center study, 49 consecutive patients with transient left ventricular dysfunction syndrome underwent Holter electrocardiographic recording on the third day after admission. A total of 27 recordings of patients with AB and 10 recordings of patients with MB were valid for analysis of HRV, nonlinear dynamic measures of HRV, detrended fluctuation analysis (DFA), and phase-rectified signal averaging (PRSA). RESULTS There were no significant differences in baseline clinical characteristics between AB and MB patients. Patients with MB showed significantly lower values for mean RR interval (835 ± 104 ms vs. 908 ± 118 ms; P < .05), 1/f power law slope (-1.28 ± 0.2 vs. -1.13 ± 0.2; P < .01), and deceleration capacity (DC) (4.6 ± 1.4 ms vs. 6.0 ± 1.4 ms; P < .01), and significantly higher values for low-frequency (LF) spectral component (5.3 ± 0.5 ln ms(2)/Hz vs. 4.8 ± 0.5 ln ms(2)/Hz), LF/high-frequency (HF) (1.7 ± 0.9 ms vs. 1.3 ± 0.6 ms; P < .05), and DFA α1 (1.09 ± 0.1 vs. 0.99 ± 0.1; P < .01) than patients with AB. There were no significant correlations between parameters of HRV, DFA, 1/f power law slope, and PRSA. CONCLUSION There are significant differences in heart rate dynamics between AB and MB syndromes. Patients with MB show stronger fractal correlations of heart rate dynamics. Thus, inhomogeneous efferent bilateral sympathetic coactivation and differences in reflex autonomic regulation may be underlying pathophysiological mechanisms for AB and MB syndromes.
Collapse
Affiliation(s)
- Hendrik Bonnemeier
- Klinik für Innere Medizin III, Kardiologie und Angiologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Oh S, Choi EK, Choi YS. Short-term autonomic denervation of the atria using botulinum toxin. Korean Circ J 2010; 40:387-90. [PMID: 20830252 PMCID: PMC2933463 DOI: 10.4070/kcj.2010.40.8.387] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 01/26/2010] [Accepted: 02/16/2010] [Indexed: 11/15/2022] Open
Abstract
Background and Objectives Major epicardial fat pads contain cardiac ganglionated plexi (GP) of the autonomic nervous system. Autonomic denervation may improve the success rate of atrial fibrillation (AF) ablation. This study was designed to elucidate the acute effects of blocking the right atrium-pulmonary vein (RA-PV) and left atrium-inferior vena cava (LA-IVC) fat pads on the electrophysiologic characteristics of the atrium and AF inducibility with a botulinum toxin injection. Materials and Methods Eight mongrel dogs were studied. The RA-PV and LA-IVC fat pads were exposed through a median thoracotomy. Botulinum toxin (BT, 50 U to each fat pad, n=6) or normal saline (NS, n=2) was injected in the entire area of two fat pads. The study protocol was applied before injection and repeated at 1, 2, 3, 4, and 5 hours thereafter. The sinus rate, ventricular rate during rapid atrial pacing with a cycle length of 50 ms, and AF inducibility were measured with and without vagal stimulation (VS). Bilateral cervical VS was applied (20 Hz, 0.2 ms, 5.6±2.0 V). AF inducibility was evaluated with burst pacing with 200 impulses at a 50-ms cycle length. Results VS effects on the sinus node and AF inducibility were eliminated a few hours after injection of BT; these changes were not observed after injection of NS. Conclusion Short-term autonomic denervation of the atria was achieved by blocking the major epicardial GP with BT.
Collapse
Affiliation(s)
- Seil Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | | | | |
Collapse
|
13
|
Salo LM, Nalivaiko E, Anderson CR, McAllen RM. Control of cardiac rate, contractility, and atrioventricular conduction by medullary raphe neurons in anesthetized rats. Am J Physiol Heart Circ Physiol 2008; 296:H318-24. [PMID: 19074673 DOI: 10.1152/ajpheart.00951.2008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sympathetic actions of medullary raphé neurons on heart rate (HR), atrioventricular conduction, ventricular contractility, and rate of relaxation were examined in nine urethane-anesthetized (1-1.5 g/kg iv), artificially ventilated rats that had been adrenalectomized and given atropine methylnitrate (1 mg/kg iv). Mean arterial pressure (MAP), ECG, and left ventricular pressure were recorded. The peak rates of rise and fall in the first derivative of left ventricular (LV) pressure (dP/dtmax and dP/dtmin, respectively) and the stimulus-R ($-R) interval were measured during brief periods of atrial pacing at 8.5 Hz before and after ventral medullary raphé neurons were activated by dl-homocysteic acid (DLH, 0.1 M) or inhibited by GABA (0.3 M) in local microinjections (90 nl). LV dP/dtmax values were corrected for the confounding effect of MAP, determined at the end of the experiments after giving propranolol (1 mg/kg iv) to block sympathetic actions on the heart. DLH microinjections into the ventral medullary raphé region increased HR by 44 +/- 2 beats/min, LV dP/dtmax by 1,055 +/- 156 mmHg/s, and the negative value of LV dP/dtmin by 729 +/- 204 mmHg/s (all, P < 0.001) while shortening the $-R interval by 2.8 +/- 0.8 ms (P < 0.01). GABA microinjections caused no significant change in HR, LV dP/dtmax, or $-R interval but reduced LV dP/dtmin from -5,974 +/- 93 to -5,548 +/- 171 mmHg/s and MAP from 115 +/- 4 to 105 +/- 5 mmHg (both, P < 0.01). Rises in tail skin temperature confirmed that GABA injections effectively inhibited raphé neurons. When activated, the neurons in the ventral medullary raphé region thus enhance atrioventricular conduction, ventricular contractility, and relaxation in parallel with HR, but they provide little or no tonic sympathetic drive to the heart.
Collapse
Affiliation(s)
- Lauren M Salo
- Howard Florey Institute, University of Melbourne, Victoria, Australia
| | | | | | | |
Collapse
|
14
|
Hiromoto K, Shimizu H, Mine T, Masuyama T, Ohyanagi M. Correlation between beat-to-beat QT interval variability and impaired left ventricular function in patients with previous myocardial infarction. Ann Noninvasive Electrocardiol 2007; 11:299-305. [PMID: 17040277 PMCID: PMC6932355 DOI: 10.1111/j.1542-474x.2006.00121.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Beat-to-beat QT interval variability (QTV) is associated with sudden cardiac death and New York Heat Association functional class severity. We sought to evaluate the relationship between QTV and left ventricular (LV) function in patients with previous myocardial infarction (MI). METHODS Fifty-nine patients with previous anterior MI were enrolled. LV ejection fraction (EF), LV end-systolic volume index (LVESVI), and LV end-diastolic volume index (LVEDVI) were measured by LV contrast angiography. QT interval was measured by automated analysis of 512-beat records of 12-lead electrocardiogram. The mean interval, standard deviation and variance in RR and QT intervals, and the QT variability index (QTVI) were calculated for each patient using two leads that corresponded with and without the infarction site. High-frequency power, low-frequency power, total-frequency power, and the ratio of low-frequency to high-frequency power in RR and QT intervals were calculated. RESULTS While measured indices of RR intervals and indices of QT intervals, which did not correspond with the infarction site, did not correlate with differences in LV function, measured indices of QT intervals, which corresponded with the infarction site, did correlate with differences in LV function. However, there were no correlations between the ratio of low-frequency to high-frequency power in QT intervals and EF or LVEDVI. Correlations between QTVI and LV function were observed, particularly between QTVI and LVESVI (r = 0.712, P < 0.0001). CONCLUSION In patients with previous anterior MI, there was variability in temporal dispersion of QT interval and a strong correlation between QTV corresponded with the infarcted site and LV function.
Collapse
Affiliation(s)
- Kenji Hiromoto
- Department of Internal Medicine, Division of Coronary Heart Disease
| | - Hiroki Shimizu
- Department of Internal Medicine, Division of Coronary Heart Disease
| | - Takanao Mine
- Department of Internal Medicine, Division of Coronary Heart Disease
| | - Tohru Masuyama
- Department of Internal Medicine, Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan
| | | |
Collapse
|
15
|
Randall DC, Brown DR, McGuirt AS, Thompson GW, Armour JA, Ardell JL. Interactions within the intrinsic cardiac nervous system contribute to chronotropic regulation. Am J Physiol Regul Integr Comp Physiol 2003; 285:R1066-75. [PMID: 12842863 DOI: 10.1152/ajpregu.00167.2003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this study was to determine how neurons within the right atrial ganglionated plexus (RAGP) and posterior atrial ganglionated plexus (PAGP) interact to modulate right atrial chronotropic, dromotropic, and inotropic function, particularly with respect to their extracardiac vagal and sympathetic efferent neuronal inputs. Surgical ablation of the PAGP (PAGPx) attenuated vagally mediated bradycardia by 26%; it reduced heart rate slowing evoked by vagal stimulation superimposed on sympathetically mediated tachycardia by 36%. RAGP ablation (RAGPx) eliminated vagally mediated bradycardia, while retaining the vagally induced suppression of sympathetic-mediated tachycardia (-83%). After combined RAGPx and PAGPx, vagal stimulation still reduced sympathetic-mediated tachycardia (-47%). After RAGPx alone and after PAGPx alone, stimulation of the vagi still produced negative dromotropic effects, although these changes were attenuated compared with the intact state. Negative dromotropic responses to vagal stimulation were further attenuated after combined ablation, but parasympathetic inhibition of atrioventricular nodal conduction was still demonstrable in most animals. Finally, neither RAGPx nor PAGPx altered autonomic regulation of right atrial inotropic function. These data indicate that multiple aggregates of neurons within the intrinsic cardiac nervous system are involved in sinoatrial nodal regulation. Whereas parasympathetic efferent neurons regulating the right atrium, including the sinoatrial node, are primarily located within the RAGP, prejunctional parasympathetic-sympathetic interactions regulating right atrial function also involve neurons within the PAGP.
Collapse
Affiliation(s)
- David C Randall
- Dept. of Physiology, Univ. of Kentucky College of Medicine, Lexington, KY 40536-0298, USA.
| | | | | | | | | | | |
Collapse
|
16
|
Arora RC, Cardinal R, Smith FM, Ardell JL, Dell'Italia LJ, Armour JA. Intrinsic cardiac nervous system in tachycardia induced heart failure. Am J Physiol Regul Integr Comp Physiol 2003; 285:R1212-23. [PMID: 12893651 DOI: 10.1152/ajpregu.00131.2003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The purpose of this study was to test the hypothesis that early-stage heart failure differentially affects the intrinsic cardiac nervous system's capacity to regulate cardiac function. After 2 wk of rapid ventricular pacing in nine anesthetized canines, cardiac and right atrial neuronal function were evaluated in situ in response to enhanced cardiac sensory inputs, stimulation of extracardiac autonomic efferent neuronal inputs, and close coronary arterial administration of neurochemicals that included nicotine. Right atrial neuronal intracellular electrophysiological properties were then evaluated in vitro in response to synaptic activation and nicotine. Intrinsic cardiac nicotine-sensitive, neuronally induced cardiac responses were also evaluated in eight sham-operated, unpaced animals. Two weeks of rapid ventricular pacing reduced the cardiac index by 54%. Intrinsic cardiac neurons of paced hearts maintained their cardiac mechano- and chemosensory transduction properties in vivo. They also responded normally to sympathetic and parasympathetic preganglionic efferent neuronal inputs, as well as to locally administered alpha-or beta-adrenergic agonists or angiotensin II. The dose of nicotine needed to modify intrinsic cardiac neurons was 50 times greater in failure compared with normal preparations. That dose failed to alter monitored cardiovascular indexes in failing preparations. Phasic and accommodating neurons identified in vitro displayed altered intracellular membrane properties compared with control, including decreased membrane resistance, indicative of reduced excitability. Early-stage heart failure differentially affects the intrinsic cardiac nervous system's capacity to regulate cardiodynamics. While maintaining its capacity to transduce cardiac mechano- and chemosensory inputs, as well as inputs from extracardiac autonomic efferent neurons, intrinsic cardiac nicotine-sensitive, local-circuit neurons differentially remodel such that their capacity to influence cardiodynamics becomes obtunded.
Collapse
Affiliation(s)
- Rakesh C Arora
- Centre de Recherche, Hôpital du Sacré-coeur, 5400 Boulevard Gouin ouest, Montréal, QC, Canada H4J 1C5
| | | | | | | | | | | |
Collapse
|