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Weiser-Bitoun I, Mori H, Nabeshima T, Tanaka N, Kudo D, Sasaki W, Narita M, Matsumoto K, Ikeda Y, Arai T, Nakano S, Sumitomo N, Senbonmatsu TA, Matsumoto K, Kato R, Morrell CH, Tsutsui K, Yaniv Y. Age-dependent contribution of intrinsic mechanisms to sinoatrial node function in humans. Sci Rep 2023; 13:18875. [PMID: 37914708 PMCID: PMC10620402 DOI: 10.1038/s41598-023-45101-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 10/16/2023] [Indexed: 11/03/2023] Open
Abstract
Average beat interval (BI) and beat interval variability (BIV) are primarily determined by mutual entrainment between the autonomic-nervous system (ANS) and intrinsic mechanisms that govern sinoatrial node (SAN) cell function. While basal heart rate is not affected by age in humans, age-dependent reductions in intrinsic heart rate have been documented even in so-called healthy individuals. The relative contributions of the ANS and intrinsic mechanisms to age-dependent deterioration of SAN function in humans are not clear. We recorded ECG on patients (n = 16 < 21 years and n = 23 41-78 years) in the basal state and after ANS blockade (propranolol and atropine) in the presence of propofol and dexmedetomidine anesthesia. Average BI and BIV were analyzed. A set of BIV features were tested to designated the "signatures" of the ANS and intrinsic mechanisms and also the anesthesia "signature". In young patients, the intrinsic mechanisms and ANS mainly contributed to long- and short-term BIV, respectively. In adults, both ANS and intrinsic mechanisms contributed to short-term BIV, while the latter also contributed to long-term BIV. Furthermore, anesthesia affected ANS function in young patients and both mechanisms in adult. The work also showed that intrinsic mechanism features can be calculated from BIs, without intervention.
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Affiliation(s)
- Ido Weiser-Bitoun
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Hitoshi Mori
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Taisuke Nabeshima
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Naomichi Tanaka
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Daisuke Kudo
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Wataru Sasaki
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Masataka Narita
- Saitama Medical University International Medical Center, Saitama, Japan
| | | | - Yoshifumi Ikeda
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Takahide Arai
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Shintaro Nakano
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Naokata Sumitomo
- Saitama Medical University International Medical Center, Saitama, Japan
| | | | - Kazuo Matsumoto
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Ritsushi Kato
- Saitama Medical University International Medical Center, Saitama, Japan
| | - Christopher H Morrell
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Kenta Tsutsui
- Saitama Medical University International Medical Center, Saitama, Japan.
- Department of Cardiovascular Medicine, Saitama Medical University International Medical Center, Saitama, Japan.
| | - Yael Yaniv
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
- Laboratory of Bioenergetic and Bioelectric Systems, The Faculty of Biomedical Engineering Technion-IIT, Haifa, Israel.
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May SM, Chiang E, Reyes A, Martir G, Patel A, Karmali S, Patel S, West S, Del Arroyo AG, Gourine AV, Ackland GL. Neuromodulation of innate immunity by remote ischaemic conditioning in humans: Experimental cross-over study. Brain Behav Immun Health 2021; 16:100299. [PMID: 34589791 PMCID: PMC8417773 DOI: 10.1016/j.bbih.2021.100299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 02/04/2023] Open
Abstract
Experimental animal studies on the mechanisms of remote ischaemic conditioning (RIC)-induced cardioprotection against ischaemia/reperfusion injury demonstrate involvement of both neuronal and humoral pathways. Autonomic parasympathetic (vagal) pathways confer organ protection through both direct innervation and/or immunomodulation, but evidence in humans is lacking. During acute inflammation, vagal release of acetylcholine suppresses CD11b expression, a critical β2-integrin regulating neutrophil adhesion to the endothelium and transmigration to sites of injury. Here, we tested the hypothesis that RIC recruits vagal activity in humans and has an anti-inflammatory effect by reducing neutrophil CD11b expression. Participants (age:50 ± 19 years; 53% female) underwent ultrasound-guided injection of local anaesthetic within the brachial plexus before applying 3 × 8 min cycles of brachial artery occlusion using a blood pressure cuff (RICblock). RIC was repeated 6 weeks later without brachial plexus block. Masked analysers quantified vagal activity (heart rate, heart rate variability (HRV)) before, and 10 min after, the last cycle of RIC. RR-interval increased after RIC (reduced heart rate) by 40 ms (95% confidence intervals (95%CI):13–66; n = 17 subjects; P = 0.003). RR-interval did not change after brachial plexus blockade (mean difference: 20 ms (95%CI:-11 to 50); P = 0.19). The high-frequency component of HRV was reduced after RICblock, but remained unchanged after RIC (P < 0.001), indicating that RIC preserved vagal activity. LPS-induced CD16+CD11b+ expression in whole blood (measured by flow cytometry) was reduced by RIC (3615 median fluorescence units (95%CI:475-6754); P = 0.026), compared with 2331 units (95%CI:-3921 to 8582); P = 0.726) after RICblock. These data suggest that in humans RIC recruits vagal cardiac and anti-inflammatory mechanisms via ischaemia/reperfusion-induced activation of sensory nerve fibres that innervate the organ undergoing RIC.
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Affiliation(s)
- Shaun M May
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Eric Chiang
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Anna Reyes
- University College Hospital NHS Trust, London, UK
| | | | - Amour Patel
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Shamir Karmali
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Sanjiv Patel
- University College Hospital NHS Trust, London, UK
| | - Simeon West
- University College Hospital NHS Trust, London, UK
| | - Ana Gutierrez Del Arroyo
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, UK
| | - Gareth L Ackland
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
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3
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Ackermann S, Laborde S, Borges U, Mosley E. Commentary: Photoplethysmography for Quantitative Assessment of Sympathetic Nerve Activity (SNA) During Cold Stress. Front Physiol 2021; 12:602745. [PMID: 34248652 PMCID: PMC8262254 DOI: 10.3389/fphys.2021.602745] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 05/21/2021] [Indexed: 11/15/2022] Open
Affiliation(s)
- Stefan Ackermann
- Institute of Psychology, Department of Performance Psychology, German Sport University Cologne, Cologne, Germany
| | - Sylvain Laborde
- Institute of Psychology, Department of Performance Psychology, German Sport University Cologne, Cologne, Germany.,Normandie Université Caen, UFR STAPS, EA 4260, Normandy, France
| | - Uirassu Borges
- Institute of Psychology, Department of Performance Psychology, German Sport University Cologne, Cologne, Germany.,Institute of Psychology, Department of Health and Social Psychology, German Sport University Cologne, Cologne, Germany
| | - Emma Mosley
- Department of Sport Science and Performance, Southampton Solent University, Southampton, United Kingdom
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4
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Signatures of the autonomic nervous system and the heart's pacemaker cells in canine electrocardiograms and their applications to humans. Sci Rep 2020; 10:9971. [PMID: 32561798 PMCID: PMC7305326 DOI: 10.1038/s41598-020-66709-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 03/13/2020] [Indexed: 01/21/2023] Open
Abstract
Heart rate and heart rate variability (HRV) are mainly determined by the autonomic nervous system (ANS), which interacts with receptors on the sinoatrial node (SAN; the heart’s primary pacemaker), and by the “coupled-clock” system within the SAN cells. HRV changes are associated with cardiac diseases. However, the relative contributions of the ANS and SAN to HRV are not clear, impeding effective treatment. To discern the SAN’s contribution, we performed HRV analysis on canine electrocardiograms containing basal and ANS-blockade segments. We also analyzed human electrocardiograms of atrial fibrillation and heart failure patients, as well as healthy aged subjects. Finally, we used a mathematical model to simulate HRV under decreased “coupled-clock” regulation. We found that (a) in canines, the SAN and ANS contribute mainly to long- and short-term HRV, respectively; (b) there is evidence suggesting a similar relative SAN contribution in humans; (c) SAN features can be calculated from beat-intervals obtained in-vivo, without intervention; (d) ANS contribution can be modeled by sines embedded in white noise; (e) HRV changes associated with cardiac diseases and aging can be interpreted as deterioration of both SAN and ANS; and (f) SAN clock-coupling can be estimated from changes in HRV. This may enable future non-invasive diagnostic applications.
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5
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Valenza G, Passamonti L, Duggento A, Toschi N, Barbieri R. Uncovering complex central autonomic networks at rest: a functional magnetic resonance imaging study on complex cardiovascular oscillations. J R Soc Interface 2020; 17:20190878. [PMID: 32183642 DOI: 10.1098/rsif.2019.0878] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
This study aims to uncover brain areas that are functionally linked to complex cardiovascular oscillations in resting-state conditions. Multi-session functional magnetic resonance imaging (fMRI) and cardiovascular data were gathered from 34 healthy volunteers recruited within the human connectome project (the '100-unrelated subjects' release). Group-wise multi-level fMRI analyses in conjunction with complex instantaneous heartbeat correlates (entropy and Lyapunov exponent) revealed the existence of a specialized brain network, i.e. a complex central autonomic network (CCAN), reflecting what we refer to as complex autonomic control of the heart. Our results reveal CCAN areas comprised the paracingulate and cingulate gyri, temporal gyrus, frontal orbital cortex, planum temporale, temporal fusiform, superior and middle frontal gyri, lateral occipital cortex, angular gyrus, precuneous cortex, frontal pole, intracalcarine and supracalcarine cortices, parahippocampal gyrus and left hippocampus. The CCAN visible at rest does not include the insular cortex, thalamus, putamen, amygdala and right caudate, which are classical CAN regions peculiar to sympatho-vagal control. Our results also suggest that the CCAN is mainly involved in complex vagal control mechanisms, with possible links with emotional processing networks.
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Affiliation(s)
- Gaetano Valenza
- Bioengineering and Robotics Research Centre 'E. Piaggio', University of Pisa, Pisa, Italy.,Deparment of Information Engineering, University of Pisa, Pisa, Italy
| | - Luca Passamonti
- Institute of Bioimaging and Molecular Physiology, National Research Council, Milano, Italy.,Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Andrea Duggento
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Nicola Toschi
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Riccardo Barbieri
- Department of Electronics, Informatics and Bioengineering, Politecnico di Milano, Milano, Italy
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6
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Sarafis ZK, Monga AK, Phillips AA, Krassioukov AV. Is Technology for Orthostatic Hypotension Ready for Primetime? PM R 2019; 10:S249-S263. [PMID: 30269810 DOI: 10.1016/j.pmrj.2018.04.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/04/2018] [Accepted: 04/12/2018] [Indexed: 01/29/2023]
Abstract
Spinal cord injury (SCI) often results in the devastating loss of motor, sensory, and autonomic function. After SCI, the interruption of descending sympathoexcitatory pathways disrupts supraspinal control of blood pressure (BP). A common clinical consequence of cardiovascular dysfunction after SCI is orthostatic hypotension (OH), a debilitating condition characterized by rapid profound decreases in BP when assuming an upright posture. OH can result in a diverse array of insidious and pernicious health consequences. Acute effects of OH include decreased cardiac filling, cerebral hypoperfusion, and associated presyncopal symptoms such as lightheadedness and dizziness. Over the long term, repetitive exposure to OH is associated with a drastically increased prevalence of heart attack and stroke, which are leading causes of death in those with SCI. Current recommendations for managing BP after SCI primarily include pharmacologic interventions with prolonged time to effect. Because most episodes of OH occur in less than 3 minutes, this delay in action often renders most pharmacologic interventions ineffective. New innovative technologies such as epidural and transcutaneous spinal cord stimulation are being explored to solve this problem. It might be possible to electrically stimulate sympathetic circuitry caudal to the injury and elicit rapid modulation of BP to manage OH. This review describes autonomic control of the cardiovascular system before injury, resulting cardiovascular consequences after SCI such as OH, and the clinical assessment tools for evaluating autonomic dysfunction after SCI. In addition, current approaches for clinically managing OH are outlined, and new promising interventions are described for managing this condition.
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Affiliation(s)
- Zoe K Sarafis
- ICORD-BSCC, University of British Columbia, Vancouver, BC, Canada(∗)
| | - Aaron K Monga
- ICORD-BSCC, University of British Columbia, Vancouver, BC, Canada(†)
| | - Aaron A Phillips
- Departments of Physiology and Pharmacology, Clinical Neurosciences, Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada(‡)
| | - Andrei V Krassioukov
- ICORD-BSCC; Experimental Medicine Program; Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia; GF Strong Rehabilitation Center, Vancouver Coastal Health; 818 West 10th Avenue, Vancouver, BC, Canada, V5Z1M9(§).
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7
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Fiskum C, Andersen TG, Bornas X, Aslaksen PM, Flaten MA, Jacobsen K. Non-linear Heart Rate Variability as a Discriminator of Internalizing Psychopathology and Negative Affect in Children With Internalizing Problems and Healthy Controls. Front Physiol 2018; 9:561. [PMID: 29875679 PMCID: PMC5974559 DOI: 10.3389/fphys.2018.00561] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/30/2018] [Indexed: 01/07/2023] Open
Abstract
Background: Internalizing psychopathology and dysregulated negative affect are characterized by dysregulation in the autonomic nervous system and reduced heart rate variability (HRV) due to increases in sympathetic activity alongside reduced vagal tone. The neurovisceral system is however, a complex nonlinear system, and nonlinear indices related to psychopathology are so far less studied in children. Essential nonlinear properties of a system can be found in two main domains: the informational domain and the invariant domain. sample entropy (SampEn) is a much-used method from the informational domain, while detrended fluctuation analysis (DFA) represents a widely-used method from the invariant domain. To see if nonlinear HRV can provide information beyond linear indices of autonomic activation, this study investigated SampEn and DFA as discriminators of internalizing psychopathology and negative affect alongside measures of vagally-mediated HRV and sympathetic activation. Material and Methods: Thirty-Two children with internalizing difficulties and 25 healthy controls (aged 9-13) were assessed with the Child Behavior Checklist and the Early Adolescent Temperament Questionnaire, Revised, giving an estimate of internalizing psychopathology, negative affect and effortful control, a protective factor against psychopathology. Five minute electrocardiogram and impedance cardiography recordings were collected during a resting baseline, giving estimates of SampEn, DFA short-term scaling exponent α1, root mean square of successive differences (RMSSD), and pre-ejection period (PEP). Between-group differences and correlations were assessed with parametric and non-parametric tests, and the relationships between cardiac variables, psychopathology and negative affect were assessed using generalized linear modeling. Results: SampEn and DFA were not significantly different between the groups. SampEn was weakly negatively related to heart rate (HR) in the controls, while DFA was moderately negatively related to RMSSD in both groups, and moderately positively related to HR in the clinical sample. SampEn was significantly associated with internalizing psychopathology and negative affect. DFA was significantly related to internalizing psychopathology. Conclusions: Higher invariant self-similarity was linked to less psychopathology. Higher informational entropy was related to less psychopathology and less negative affect, and may provide an index of the organizational flexibility of the neurovisceral system.
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Affiliation(s)
- Charlotte Fiskum
- Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tonje G. Andersen
- Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Xavier Bornas
- Department of Psychology, University of the Balearic Islands, Palma, Spain
| | - Per M. Aslaksen
- Department of Psychology, The Arctic University of Norway, Tromsø, Norway
| | - Magne A. Flaten
- Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Karl Jacobsen
- Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
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8
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Biering-Sørensen F, Biering-Sørensen T, Liu N, Malmqvist L, Wecht JM, Krassioukov A. Alterations in cardiac autonomic control in spinal cord injury. Auton Neurosci 2018; 209:4-18. [DOI: 10.1016/j.autneu.2017.02.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 01/30/2017] [Accepted: 02/14/2017] [Indexed: 01/22/2023]
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Patel HC, Hayward C, Wardle AJ, Middleton L, Lyon AR, Di Mario C, Salukhe TV, Sutton R, Rosen SD. The effect of head-up tilt upon markers of heart rate variability in patients with atrial fibrillation. Ann Noninvasive Electrocardiol 2017; 23:e12511. [PMID: 29034583 DOI: 10.1111/anec.12511] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 09/21/2017] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Heart rate variability (HRV) analysis is uncommonly undertaken in patients with atrial fibrillation (AF) due to an assumption that ventricular response is random. We sought to determine the effects of head-up tilt (HUT), a stimulus known to elicit an autonomic response, on HRV in patients with AF; we contrasted the findings with those of patients in sinus rhythm (SR). METHODS Consecutive, clinically indicated tilt tests were examined for 207 patients: 176 in SR, 31 in AF. Patients in AF were compared to an age-matched SR cohort (n = 69). Five minute windows immediately before and after tilting were analyzed using time-domain, frequency-domain and nonlinear HRV parameters. Continuous, noninvasive assessment of blood pressure, heart rate and stroke volume were available in the majority of patients. RESULTS There were significant differences at baseline in all HRV parameters between AF and age matched SR. HUT produced significant hemodynamic changes, regardless of cardiac rhythm. Coincident with these hemodynamic changes, patients in AF had a significant increase in median [quartile 1, 2] DFA-α2 (+0.14 [-0.03, 0.32], p < .005) and a decrease in sample entropy (-0.17 [-0.50, -0.01], p < .005). CONCLUSION In the SR cohort, increasing age was associated with fewer HRV changes on tilting. Patients with AF had blunted HRV responses to tilting, mirroring those seen in an age matched SR group. It is feasible to measure HRV in patients with AF and the changes observed on HUT are comparable to those seen in patients in sinus rhythm.
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Affiliation(s)
- Hitesh C Patel
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, United Kingdom.,National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Carl Hayward
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, United Kingdom.,National Heart and Lung Institute, Imperial College, London, United Kingdom
| | | | - Lee Middleton
- Department of Cardiology, Ealing Hospital, Southall, United Kingdom
| | - Alexander R Lyon
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, United Kingdom.,National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Carlo Di Mario
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, United Kingdom.,National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Tushar V Salukhe
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, United Kingdom.,National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Richard Sutton
- National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Stuart D Rosen
- National Heart and Lung Institute, Imperial College, London, United Kingdom.,Department of Cardiology, Ealing Hospital, Southall, United Kingdom
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10
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Silva LEV, Silva CAA, Salgado HC, Fazan R. The role of sympathetic and vagal cardiac control on complexity of heart rate dynamics. Am J Physiol Heart Circ Physiol 2017; 312:H469-H477. [DOI: 10.1152/ajpheart.00507.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 12/05/2016] [Accepted: 12/20/2016] [Indexed: 11/22/2022]
Abstract
Analysis of heart rate variability (HRV) by nonlinear approaches has been gaining interest due to their ability to extract additional information from heart rate (HR) dynamics that are not detectable by traditional approaches. Nevertheless, the physiological interpretation of nonlinear approaches remains unclear. Therefore, we propose long-term (60 min) protocols involving selective blockade of cardiac autonomic receptors to investigate the contribution of sympathetic and parasympathetic function upon nonlinear dynamics of HRV. Conscious male Wistar rats had their electrocardiogram (ECG) recorded under three distinct conditions: basal, selective (atenolol or atropine), or combined (atenolol plus atropine) pharmacological blockade of autonomic muscarinic or β1-adrenergic receptors. Time series of RR interval were assessed by multiscale entropy (MSE) and detrended fluctuation analysis (DFA). Entropy over short (1 to 5, MSE1–5) and long (6 to 30, MSE6–30) time scales was computed, as well as DFA scaling exponents at short (αshort, 5 ≤ n ≤ 15), mid (αmid, 30 ≤ n ≤ 200), and long (αlong, 200 ≤ n ≤ 1,700) window sizes. The results show that MSE1–5 is reduced under atropine blockade and MSE6–30 is reduced under atropine, atenolol, or combined blockade. In addition, while atropine expressed its maximal effect at scale six, the effect of atenolol on MSE increased with scale. For DFA, αshort decreased during atenolol blockade, while the αmid increased under atropine blockade. Double blockade decreased αshort and increased αlong. Results with surrogate data show that the dynamics during combined blockade is not random. In summary, sympathetic and vagal control differently affect entropy (MSE) and fractal properties (DFA) of HRV. These findings are important to guide future studies. NEW & NOTEWORTHY Although multiscale entropy (MSE) and detrended fluctuation analysis (DFA) are recognizably useful prognostic/diagnostic methods, their physiological interpretation remains unclear. The present study clarifies the effect of the cardiac autonomic control on MSE and DFA, assessed during long periods (1 h). These findings are important to help the interpretation of future studies.
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Affiliation(s)
| | | | - Helio Cesar Salgado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Rubens Fazan
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
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11
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Sharif H, Allison D, O'Leary D, Ditor D. Reproducibility of the QT-variability index in individuals with spinal cord injury. Auton Neurosci 2016; 195:16-9. [DOI: 10.1016/j.autneu.2016.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 12/16/2015] [Accepted: 02/07/2016] [Indexed: 11/28/2022]
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12
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Sharif H, Millar PJ, Incognito AV, Ditor DS. Non-invasive electrocardiographic assessments of cardiac autonomic modulation in individuals with spinal cord injury. Spinal Cord 2015; 54:166-71. [DOI: 10.1038/sc.2015.207] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 10/09/2015] [Accepted: 10/16/2015] [Indexed: 12/11/2022]
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13
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Wecht JM, La Fountaine MF, Handrakis JP, West CR, Phillips A, Ditor DS, Sharif H, Bauman WA, Krassioukov AV. Autonomic Nervous System Dysfunction Following Spinal Cord Injury: Cardiovascular, Cerebrovascular, and Thermoregulatory Effects. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2015. [DOI: 10.1007/s40141-015-0093-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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14
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Weippert M, Behrens K, Rieger A, Kumar M, Behrens M. Effects of breathing patterns and light exercise on linear and nonlinear heart rate variability. Appl Physiol Nutr Metab 2015; 40:762-8. [DOI: 10.1139/apnm-2014-0493] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Despite their use in cardiac risk stratification, the physiological meaning of nonlinear heart rate variability (HRV) measures is not well understood. The aim of this study was to elucidate effects of breathing frequency, tidal volume, and light exercise on nonlinear HRV and to determine associations with traditional HRV indices. R–R intervals, blood pressure, minute ventilation, breathing frequency, and respiratory gas concentrations were measured in 24 healthy male volunteers during 7 conditions: voluntary breathing at rest, and metronome guided breathing (0.1, 0.2 and 0.4 Hz) during rest, and cycling, respectively. The effect of physical load was significant for heart rate (HR; p < 0.001) and traditional HRV indices SDNN, RMSSD, lnLFP, and lnHFP (p < 0.01 for all). It approached significance for sample entropy (SampEn) and correlation dimension (D2) (p < 0.1 for both), while HRV detrended fluctuation analysis (DFA) measures DFAα1 and DFAα2 were not affected by load condition. Breathing did not affect HR but affected all traditional HRV measures. D2 was not affected by breathing; DFAα1 was moderately affected by breathing; and DFAα2, approximate entropy (ApEn), and SampEn were strongly affected by breathing. DFAα1 was strongly increased, whereas DFAα2, ApEn, and SampEn were decreased by slow breathing. No interaction effect of load and breathing pattern was evident. Correlations to traditional HRV indices were modest (r from –0.14 to –0.67, p < 0.05 to <0.01). In conclusion, while light exercise does not significantly affect short-time HRV nonlinear indices, respiratory activity has to be considered as a potential contributor at rest and during light dynamic exercise.
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Affiliation(s)
- Matthias Weippert
- Institute of Sport Science, University of Rostock, Rostock, Mecklenburg-Vorpommern, Germany
- Institute of Exercise Physiology and Public Health, Rostock, Mecklenburg-Vorpommern, Germany
| | - Kristin Behrens
- Institute of Exercise Physiology and Public Health, Rostock, Mecklenburg-Vorpommern, Germany
| | - Annika Rieger
- Institute of Exercise Physiology and Public Health, Rostock, Mecklenburg-Vorpommern, Germany
| | - Mohit Kumar
- University of Rostock, Rostock, Mecklenburg-Vorpommern, Germany
| | - Martin Behrens
- Institute of Sport Science, University of Rostock, Rostock, Mecklenburg-Vorpommern, Germany
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15
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Sharif H, Cotie LM, La Fountaine MF, Ditor DS. The influence of cardiac autonomic activity on the QT-variability index in able-bodied and incomplete spinal cord injured individuals. Auton Neurosci 2015; 190:46-52. [DOI: 10.1016/j.autneu.2015.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 03/03/2015] [Accepted: 04/11/2015] [Indexed: 11/26/2022]
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16
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Serra-Añó P, Montesinos LL, Morales J, López-Bueno L, Gomis M, García-Massó X, González LM. Heart rate variability in individuals with thoracic spinal cord injury. Spinal Cord 2014; 53:59-63. [DOI: 10.1038/sc.2014.207] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 12/20/2022]
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17
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Millar PJ, McGowan CL, Cornelissen VA, Araujo CG, Swaine IL. Evidence for the role of isometric exercise training in reducing blood pressure: potential mechanisms and future directions. Sports Med 2014; 44:345-56. [PMID: 24174307 DOI: 10.1007/s40279-013-0118-x] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hypertension, or the chronic elevation in resting arterial blood pressure (BP), is a significant risk factor for cardiovascular disease and estimated to affect ~1 billion adults worldwide. The goals of treatment are to lower BP through lifestyle modifications (smoking cessation, weight loss, exercise training, healthy eating and reduced sodium intake), and if not solely effective, the addition of antihypertensive medications. In particular, increased physical exercise and decreased sedentarism are important strategies in the prevention and management of hypertension. Current guidelines recommend both aerobic and dynamic resistance exercise training modalities to reduce BP. Mounting prospective evidence suggests that isometric exercise training in normotensive and hypertensive (medicated and non-medicated) cohorts of young and old participants may produce similar, if not greater, reductions in BP, with meta-analyses reporting mean reductions of between 10 and 13 mmHg systolic, and 6 and 8 mmHg diastolic. Isometric exercise training protocols typically consist of four sets of 2-min handgrip or leg contractions sustained at 20-50 % of maximal voluntary contraction, with each set separated by a rest period of 1-4 min. Training is usually completed three to five times per week for 4-10 weeks. Although the mechanisms responsible for these adaptations remain to be fully clarified, improvements in conduit and resistance vessel endothelium-dependent dilation, oxidative stress, and autonomic regulation of heart rate and BP have been reported. The clinical significance of isometric exercise training, as a time-efficient and effective training modality to reduce BP, warrants further study. This evidence-based review aims to summarize the current state of knowledge regarding the effects of isometric exercise training on resting BP.
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Affiliation(s)
- Philip J Millar
- Division of Cardiology, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada
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18
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Currie KD, Rosen LM, Millar PJ, McKelvie RS, MacDonald MJ. Heart rate recovery and heart rate variability are unchanged in patients with coronary artery disease following 12 weeks of high-intensity interval and moderate-intensity endurance exercise training. Appl Physiol Nutr Metab 2013; 38:644-50. [PMID: 23724882 DOI: 10.1139/apnm-2012-0354] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Decreased heart rate variability and attenuated heart rate recovery following exercise are associated with an increased risk of mortality in cardiac patients. This study investigated the effects of 12 weeks of moderate-intensity endurance exercise (END) and a novel low-volume high-intensity interval exercise protocol (HIT) on measures of heart rate recovery and heart rate variability in patients with coronary artery disease (CAD). Fourteen males with CAD participated in 12 weeks of END or HIT training, each consisting of 2 supervised exercise sessions per week. END consisted of 30-50 min of continuous cycling at 60% peak power output (PPO). HIT involved ten 1-min intervals at 88% PPO separated by 1-min intervals at 10% PPO. Heart rate recovery at 1 min and 2 min was measured before and after training (pre- and post-training, respectively) using a submaximal exercise bout. Resting time and spectral and nonlinear domain measures of heart rate variability were calculated. Following 12 weeks of END and HIT, there was no change in heart rate recovery at 1 min (END, 40 ± 12 beats·min(-1) vs. 37 ± 19 beats·min(-1); HIT, 31 ± 8 beats·min(-1) vs. 35 ± 8 beats·min(-1); p ≥ 0.05 for pre- vs. post-training) or 2 min (END, 44 ± 18 beats·min(-1) vs. 43 ± 19 beats·min(-1); HIT, 42 ± 10 beats·min(-1) vs. 50 ± 6 beats·min(-1); p ≥ 0.05 for pre- vs. post-training). All heart rate variability indices were unchanged following END and HIT training. In conclusion, neither END nor HIT exercise programs elicited training-induced improvements in cardiac autonomic function in patients with CAD. The absence of improvements with training may be attributed to the optimal medical management and normative pretraining state of our sample.
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Affiliation(s)
- Katharine D Currie
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
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19
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Millar PJ, Levy AS, McGowan CL, McCartney N, MacDonald MJ. Isometric handgrip training lowers blood pressure and increases heart rate complexity in medicated hypertensive patients. Scand J Med Sci Sports 2012; 23:620-6. [PMID: 22260503 DOI: 10.1111/j.1600-0838.2011.01435.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2011] [Indexed: 11/27/2022]
Abstract
Hypertension is characterized by elevated blood pressure (BP) and autonomic dysfunction, both thought to be improved with exercise training. Isometric handgrip (IHG) training may represent a beneficial, time-effective exercise therapy. We investigated the effects of IHG training on BP and traditional and nonlinear measures of heart rate variability (HRV). Pre- and post-measurements of BP and HRV were determined in 23 medicated hypertensive participants (mean ± SEM, 66 ± 2 years) following either 8 weeks of IHG training (n = 13) or control (n = 10). IHG exercise consisted of four unilateral 2-min isometric contractions at 30% of maximal voluntary contraction, each separated by 4 min of rest. IHG training was performed 3 days/week for 8 weeks. IHG training decreased systolic BP (125 ± 3 mmHg to 120 ± 2 mmHg, P < 0.05) and mean BP (90 ± 2 mmHg to 87 ± 2 mmHg, P < 0.05), while sample entropy was increased (1.07 ± 0.1 to 1.35 ± 0.1, P < 0.05) and the fractal scaling distance score was decreased (0.34 ± 0.1 to 0.19 ± 0.1, P < 0.05). No significant changes were observed in traditional spectral or time-domain measures of HRV or control participants. IHG training improves nonlinear HRV, but not traditional HRV, while reducing systolic and mean BP. These results may highlight the benefits of IHG training for patients with primary hypertension.
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Affiliation(s)
- P J Millar
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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20
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Agiovlasitis S, Baynard T, Pitetti KH, Fernhall B. Heart rate complexity in response to upright tilt in persons with Down syndrome. RESEARCH IN DEVELOPMENTAL DISABILITIES 2011; 32:2102-2107. [PMID: 21985994 DOI: 10.1016/j.ridd.2011.08.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 08/18/2011] [Indexed: 05/31/2023]
Abstract
People with Down syndrome (DS) show altered autonomic response to sympatho-excitation. Cardiac autonomic modulation may be examined with heart rate (HR) complexity which is associated uniquely with cardiovascular risk. This study examined whether the response of HR complexity to passive upright tilt differs between persons with and without DS and whether potential between-group differences in this response are accounted for by differences in body mass index (BMI). The electrocardiogram of 16 persons with DS (8 women, 8 men) and 16 persons without DS (8 women, 8 men) was recorded during 10 min of supine rest and 10 min of upright tilt. For each participant, 550 continuous, steady state, and ectopy-free R-R intervals under each condition were analyzed. Dependent variables were approximate entropy, correlation dimension, StatAv, and the mean R-R interval. In response to tilt, changes in approximate entropy and correlation dimension were reduced in participants with DS (p<0.05). These differences were explained by higher BMI in participants with DS. StatAv increased in persons with DS (p < 0.05) and stayed the same in those without DS even when controlling for BMI. The response of R-R interval did not differ between groups. None of the variables differed between groups at rest. Therefore, people with DS show smaller decrease in HR complexity in response to upright tilt than people without DS partially due to their higher BMI. Resting HR complexity does not differ between persons with and without DS. These results may have implications for cardiovascular risk in people with DS.
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Affiliation(s)
- Stamatis Agiovlasitis
- Department of Kinesiology, Mississippi State University, 233 McCarthy Gym, PO Box 6186, Mississippi State, MS 39762, USA.
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Mateo M, Blasco-Lafarga C, Martínez-Navarro I, Guzmán JF, Zabala M. Heart rate variability and pre-competitive anxiety in BMX discipline. Eur J Appl Physiol 2011; 112:113-23. [PMID: 21503698 DOI: 10.1007/s00421-011-1962-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Accepted: 04/04/2011] [Indexed: 10/18/2022]
Abstract
Altered neural mechanisms implying autonomic functioning have been described related to anxiety. Pre-competitive stress may be considered as an anxiety-state associated with disorders (i.e. somatic and cognitive alterations, and self-confidence worsening) that severely impair sport performance, conditioning short-lasting strength-related disciplines like BMX. From the psychological perspective, coaches use questionnaires like CSAI-2R to identify these alterations. However, with the emergence of psycho-physiological and non-linear approaches, recent studies suggest that HRV analysis provides a non-invasive tool to assess them. Hence, our purpose was to analyze how BMX competition affects subjective perception of anxiety, and if this emotional alteration is reflected in HR dynamics, analyzed both linear and nonlinearly, exploring the evolution of this relationship in a 2-day competition. Eleven male athletes from the BMX Spanish National Team were assessed from baseline HRV the morning of a training session (rT) and on two successive days of competition (rC1 and rC2), repeating HRV recording with CSAI-2R 20 min prior to training (aT) and competition (pre-competitive: aC1 and aC2). Repeated measures MANOVA showed significant vagal slow-down responses in aC1 and aC2 comparing not only with aT, but also comparing with rT, rC1 and rC2, coinciding with significant greater scores for the somatic and cognitive anxiety (SA and CA) in aC1 and aC2 versus aT. Pearson analysis showed a large and positive correlation between α1 and SA in C1, and close to it between SampEn and CA in aC2; both were confirmed by Bland-Altman chart analysis. Our results confirm that HRV analysis provide a complementary tool to assess competitive pressure.
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