251
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Demirel S, Celi de la Torre JA, Bruijnen H, Martin E, Popp E, Böckler D, Attigah N. Effect of Superficial Cervical Plexus Block on Baroreceptor Sensitivity in Patients Undergoing Carotid Endarterectomy. J Cardiothorac Vasc Anesth 2016; 30:309-16. [PMID: 26718664 DOI: 10.1053/j.jvca.2015.08.026] [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: 07/18/2015] [Indexed: 11/11/2022]
Abstract
OBJECTIVES Regional anesthesia for patients undergoing carotid endarterectomy is associated with improved intraoperative hemodynamic stability compared with general anesthesia. The authors hypothesized that the reported advantages might be related to attenuated ipsilateral baroreflex control of blood pressure, caused by chemical denervation of the carotid bulb baroreceptor nerve fibers. DESIGN A prospective cohort study. SETTING Single-center university hospital. PARTICIPANTS The study included 46 patients undergoing carotid endarterectomy using superficial cervical block. INTERVENTIONS A noninvasive computational periprocedural measurement of baroreceptor sensitivity was performed in all patients. Two groups were formed, depending on the patients' subjective response to surgical stimulation regarding the necessity of additional intraoperative local anesthesia (LA) administration on the carotid bulb. Group A (block alone) included 23 patients who required no additional anesthesia, and group B (block + LA) consisted of 23 patients who required additional anesthesia. MEASUREMENTS AND MAIN RESULTS Baroreceptor sensitivity showed no significant change after application of the block in both groups (group A: median [IQR], 5.19 [3.07-8.54] v 4.96 [3.1-9.07]; p = 0.20) (group B: median [IQR], 4.47 [3.36-8.09] v 4.53 [3.29-8.01]; p = 0.55). There was a significant decrease in baroreceptor sensitivity in group B after intraoperative LA administration (median [IQR], 4.53 [3.29-8.01] v 3.31 [2.26-7.31]; p = 0.04). CONCLUSIONS Standard superficial cervical plexus block did not impair local baroreceptor function, and, therefore, it was not related to improved cerebral perfusion in awake patients undergoing carotid endarterectomy. However, direct infiltration of the carotid bulb was associated with the expected attenuation of baroreflex sensitivity.
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Affiliation(s)
- Serdar Demirel
- Department of Vascular and Endovascular Surgery, University Hospital of Heidelberg, Heidelberg, Germany;.
| | | | - Hans Bruijnen
- Department of Vascular and Thoracic Surgery, Augsburg City Hospital, University of Ludwig-Maximillians, Munich, Germany
| | - Eike Martin
- Department of Anesthesiology, University Hospital of Heidelberg, Heidelberg, Germany
| | - Erik Popp
- Department of Anesthesiology, University Hospital of Heidelberg, Heidelberg, Germany
| | - Dittmar Böckler
- Department of Vascular and Endovascular Surgery, University Hospital of Heidelberg, Heidelberg, Germany
| | - Nicolas Attigah
- Department of Vascular Surgery, City Hospital Triemli, Zurich, Switzerland
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252
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Taylor CE, Witter T, El Sayed K, Hissen SL, Johnson AW, Macefield VG. Relationship between spontaneous sympathetic baroreflex sensitivity and cardiac baroreflex sensitivity in healthy young individuals. Physiol Rep 2015; 3:3/11/e12536. [PMID: 26564059 PMCID: PMC4673619 DOI: 10.14814/phy2.12536] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Low baroreflex sensitivity (BRS) is associated with elevated cardiovascular risk. However, the evidence is based primarily on measurements of cardiac BRS. It cannot be assumed that cardiac or sympathetic BRS alone represent a true reflection of baroreflex control of blood pressure. The aim of this study was to examine the relationship between spontaneous sympathetic and cardiac BRS in healthy, young individuals. Continuous measurements of blood pressure, heart rate, and muscle sympathetic nerve activity (MSNA) were made under resting conditions in 50 healthy individuals (18–28 years). Sympathetic BRS was quantified by plotting MSNA burst incidence against diastolic pressure (sympathetic BRSinc), and by plotting total MSNA against diastolic pressure (sympathetic BRStotal). Cardiac BRS was quantified by plotting R-R interval against systolic pressure using the sequence method. Significant sympathetic BRSinc and cardiac BRS slopes were obtained for 42 participants. A significant positive correlation was found between sympathetic BRSinc and cardiac BRS (r = 0.31, P = 0.049). Among this group, significant sympathetic baroreflex slopes were obtained for 39 participants when plotting total MSNA against diastolic pressure. In this subset, a significant positive correlation was observed between sympathetic BRStotal and cardiac BRS (r = 0.40, P = 0.012). When males and females were assessed separately, these modest relationships only remained significant in females. Analysis by gender revealed correlations in the females between sympathetic BRSinc and cardiac BRS (r = 0.49, P = 0.062), and between sympathetic BRStotal and cardiac BRS (r = 0.57, P = 0.025). These findings suggest that gender interactions exist in baroreflex control of blood pressure, and that cardiac BRS is not appropriate for estimating overall baroreflex function in healthy, young populations. This relationship warrants investigation in aging and clinical populations.
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Affiliation(s)
- Chloe E Taylor
- School of Science and Health, University of Western Sydney, Sydney, Australia
| | - Trevor Witter
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | | | - Sarah L Hissen
- School of Science and Health, University of Western Sydney, Sydney, Australia
| | - Aaron W Johnson
- School of Medicine, University of Western Sydney, Sydney, Australia
| | - Vaughan G Macefield
- School of Medicine, University of Western Sydney, Sydney, Australia Neuroscience Research Australia, Sydney, Australia
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253
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Abstract
The body responds to environmental stressors by triggering autonomic reflexes in the pulmonary receptors, baroreceptors, and chemoreceptors to maintain homeostasis. Numerous studies have shown that exposure to various gases and airborne particles can alter the functional outcome of these reflexes, particularly with respect to the cardiovascular system. Modulation of autonomic neural input to the heart and vasculature following direct activation of sensory nerves in the respiratory system, elicitation of oxidative stress and inflammation, or through other mechanisms is one of the primary ways that exposure to air pollution affects normal cardiovascular function. Any homeostatic process that utilizes the autonomic nervous system to regulate organ function might be affected. Thus, air pollution and other inhaled environmental irritants have the potential to alter both local airway function and baro- and chemoreflex responses, which modulate autonomic control of blood pressure and detect concentrations of key gases in the body. While each of these reflex pathways causes distinct responses, the systems are heavily integrated and communicate through overlapping regions of the brainstem to cause global effects. This short review summarizes the function of major pulmonary sensory receptors, baroreceptors, and carotid body chemoreceptors and discusses the impacts of air pollution exposure on these systems.
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254
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Chirico D, Liu J, Klentrou P, Shoemaker JK, O'Leary DD. The Effects of Sex and Pubertal Maturation on Cardiovagal Baroreflex Sensitivity. J Pediatr 2015; 167:1067-73. [PMID: 26340872 DOI: 10.1016/j.jpeds.2015.07.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 06/22/2015] [Accepted: 07/28/2015] [Indexed: 01/03/2023]
Abstract
OBJECTIVE To examine baroreflex sensitivity (BRS) across different stages of pubertal maturation in healthy children and adolescents. STUDY DESIGN This study was cross-sectional and included 104 participants (53 males and 51 females) aged 8-18 years old. Participants were organized into 5 pubertal groups based on the criteria of Tanner; prepubertal (Tanner 1, n = 19), early-pubertal (Tanner 2, n = 16), peripubertal (Tanner 3, n = 24), late-pubertal (Tanner 4, n = 23), and postpubertal (Tanner 5 and 6, n = 22). Adiposity (fat-free mass, fat mass, and body fat%), body mass index, and demographic variables were collected. Beat-by-beat blood pressure and R-R interval were collected during supine rest to determine BRS. BRS was assessed by transfer function analysis in the low frequency range (0.05-0.15 Hz). RESULTS The results demonstrated a sex-by-maturation interaction [F(4, 94) = 3.202, P = .019]. BRS decreased from early-to postpuberty in males (30 [7.1] vs 13.2 [7.8] ms/mm Hg), and remained unchanged in females. This led to significantly greater BRS in females compared with males, postpuberty (27 [7.3] vs 13.2 [7.8] ms/mm Hg). CONCLUSIONS Controlling for both sex and maturation when examining BRS in children and adolescents with cardiovascular disease risk factors will aid in interpreting abnormally high or low BRS values.
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Affiliation(s)
- Daniele Chirico
- Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Jian Liu
- Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Panagiota Klentrou
- Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - J Kevin Shoemaker
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada
| | - Deborah D O'Leary
- Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario, Canada; Brock-Niagara Centre for Health and Well-Being, Brock University, St. Catharines, Ontario, Canada.
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255
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Spontaneous baroreceptor reflex sensitivity for risk stratification of heart failure patients: optimal cut-off and age effects. Clin Sci (Lond) 2015; 129:1163-72. [DOI: 10.1042/cs20150341] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 10/01/2015] [Indexed: 11/17/2022]
Abstract
This study provides statistical support for 3 ms/mmHg as a cut-off value that is the identifier of a homogeneous group of patients with depressed BRS, and highlights the robustness of this threshold in risk stratification due to its age-independent prognostic value.
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256
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Hernando D, Sörnmo L, Sandberg F, Laguna P, Llamedo M, Bailón R. Identification of patients prone to hypotension during hemodialysis based on the analysis of cardiovascular signals. Med Eng Phys 2015; 37:1156-61. [PMID: 26525780 DOI: 10.1016/j.medengphy.2015.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
Intradialytic hypotension (IDH) is a major complication during hemodialysis treatment, and therefore it is highly desirable to identify, at an early stage during treatment, whether the patient is prone to IDH. Heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were analyzed during the first 30 min of treatment to assess information on the autonomic nervous system. Using the sequential floating forward selection method and linear classification, the set of features with the best discriminative power was selected, resulting in an accuracy of 92.1%. Using a classifier based on the HRV features only, thereby avoiding that continuous blood pressure has to be recorded, accuracy decreased to 90.2%. The results suggest that an HRV-based classifier is useful for determining whether a patient is prone to IDH at the beginning of the treatment.
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Affiliation(s)
- D Hernando
- Biomedical Signal Interpretation & Computational Simulation (BSICoS) Group, Aragón Institute of Engineering Research (I3A), IIS Aragón, University of Zaragoza, Spain; Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain.
| | - L Sörnmo
- Signal Processing Group, Department of Biomedical Engineering and Center for Integrative Electrocardiology, Lund University, Lund, Sweden.
| | - F Sandberg
- Signal Processing Group, Department of Biomedical Engineering and Center for Integrative Electrocardiology, Lund University, Lund, Sweden.
| | - P Laguna
- Biomedical Signal Interpretation & Computational Simulation (BSICoS) Group, Aragón Institute of Engineering Research (I3A), IIS Aragón, University of Zaragoza, Spain; Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain.
| | - M Llamedo
- Biomedical Signal Interpretation & Computational Simulation (BSICoS) Group, Aragón Institute of Engineering Research (I3A), IIS Aragón, University of Zaragoza, Spain; Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain.
| | - R Bailón
- Biomedical Signal Interpretation & Computational Simulation (BSICoS) Group, Aragón Institute of Engineering Research (I3A), IIS Aragón, University of Zaragoza, Spain; Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain.
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257
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Palamarchuk IS, Baker J, Kimpinski K. The utility of Valsalva maneuver in the diagnoses of orthostatic disorders. Am J Physiol Regul Integr Comp Physiol 2015; 310:R243-52. [PMID: 26491102 DOI: 10.1152/ajpregu.00290.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/16/2015] [Indexed: 11/22/2022]
Abstract
The objective of this study was to assess hemodynamic responses and baroreflex sensitivity (BRS) indexes during Valsalva maneuver (VM) and head-up tilt (HUT) testing in orthostatic intolerance (OI). Patients with neurogenic orthostatic hypotension (NOH, n = 26), postural tachycardia syndrome (n = 26) and symptomatic OI (n = 14) were compared with healthy population (control, n = 107) and inappropriate sinus tachycardia (n = 7). Hemodynamic assessment included patterning and quantification with vagal and adrenergic BRS (BRSa/BRSa1). In NOH, cardiovagal systolic blood pressure (SBP) decrements in VM and HUT were correlated (r = 0.660, P < 0.001); a "V" pattern of VM indicated α-BRSa failure. Yet BRSa1 did not reveal changes vs. control (P > 0.05) or was not applicable in 60% of NOH. In symptomatic OI, compared with control, cardiovagal SBP decrements were larger (P < 0.05); higher BRSa1 contradicted higher adrenergic index (Composite Autonomic Severity Score). Overshoot in phase IV dipped below baseline or dropped ≥ 10 mmHg over 8 s in postural tachycardia syndrome ("N" pattern), but by 3 s in inappropriate sinus tachycardia ("M" pattern). Visualization of distinct VM patterns allows primary evaluation of autonomic dysfunction and differentiation of the various forms of OI. BRSa1 evaluation is compromised by pathological SBP patterns. VM patterning is a valuable nonpostural supplement to HUT capable of detecting and differentiating OI.
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Affiliation(s)
- Iryna S Palamarchuk
- Department of Clinical Neurological Sciences, University Hospital, London Health Sciences Centre, London, Ontario, Canada; and Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Jacquie Baker
- Department of Clinical Neurological Sciences, University Hospital, London Health Sciences Centre, London, Ontario, Canada; and
| | - Kurt Kimpinski
- Department of Clinical Neurological Sciences, University Hospital, London Health Sciences Centre, London, Ontario, Canada; and Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
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258
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Comparison of effects of OSA treatment by MAD and by CPAP on cardiac autonomic function during daytime. Sleep Breath 2015; 20:635-46. [PMID: 26463420 PMCID: PMC4850173 DOI: 10.1007/s11325-015-1265-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 09/07/2015] [Accepted: 09/21/2015] [Indexed: 10/26/2022]
Abstract
PURPOSE The present study compared the effects of mandibular advancement therapy (MAD) with continuous positive airway pressure therapy (CPAP) on daytime cardiac autonomic modulation in a wide range of obstructive sleep apnea (OSA) patients under controlled conditions in a randomized, two-period crossover trial. METHODS Forty OSA patients underwent treatment with MAD and with CPAP for 12 weeks each. At baseline and after each treatment period, patients were assessed by polysomnography as well as by a daytime cardiac autonomic function test that measured heart rate variability (HRV), continuous blood pressure (BP), and baroreceptor sensitivity (BRS) under conditions of spontaneous breathing, with breathing at 6, 12, and 15/min. RESULTS Both CPAP and MAD therapy substantially eliminated apneas and hypopneas. CPAP had a greater effect. During daytime with all four conditions of controlled breathing, three-minute mean values of continuous diastolic BP were significantly reduced for both MAD and CPAP therapy. At the same time, selective increases due to therapy with MAD were found for HRV high frequency (HF) values. No changes were observed for BRS in either therapy mode. CONCLUSIONS These findings indicate that both MAD and CPAP result in similar beneficial changes in cardiac autonomic function during daytime, especially in blood pressure. CPAP is more effective than MAD in eliminating respiratory events.
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259
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Phillips AA, Krassioukov AV. Contemporary Cardiovascular Concerns after Spinal Cord Injury: Mechanisms, Maladaptations, and Management. J Neurotrauma 2015; 32:1927-42. [PMID: 25962761 DOI: 10.1089/neu.2015.3903] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cardiovascular (CV) issues after spinal cord injury (SCI) are of paramount importance considering they are the leading cause of death in this population. Disruption of autonomic pathways leads to a highly unstable CV system, with impaired blood pressure (BP) and heart rate regulation. In addition to low resting BP, on a daily basis the majority of those with SCI suffer from transient episodes of aberrantly low and high BP (termed orthostatic hypotension and autonomic dysreflexia, respectively). In fact, autonomic issues, including resolution of autonomic dysreflexia, are frequently ranked by individuals with high-level SCI to be of greater priority than walking again. Owing to a combination of these autonomic disturbances and a myriad of lifestyle factors, the pernicious process of CV disease is accelerated post-SCI. Unfortunately, these secondary consequences of SCI are only beginning to receive appropriate clinical attention. Immediately after high-level SCI, major CV abnormalities present in the form of neurogenic shock. After subsiding, new issues related to BP instability arise, including orthostatic hypotension and autonomic dysreflexia. This review describes autonomic control over the CV system before injury and the mechanisms underlying CV abnormalities post-SCI, while also detailing the end-organ consequences, including those of the heart, as well as the systemic and cerebral vasculature. The tertiary impact of CV dysfunction will also be discussed, such as the potential impediment of rehabilitation, and impaired cognitive function. In the recent past, our understanding of autonomic dysfunctions post-SCI has been greatly enhanced; however, it is vital to further develop our understanding of the long-term consequences of these conditions, which will equip us to better manage CV disease morbidity and mortality in this population.
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Affiliation(s)
- Aaron A Phillips
- 1 Center for Heart, Lung, and Vascular Health, Faculty of Health and Social Development, University of British Columbia , Kelowna, British Columbia, Canada .,2 Experimental Medicine Program, Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .,3 International Collaboration on Repair Discoveries (ICORD), University of British Columbia , Vancouver, British Columbia, Canada
| | - Andrei V Krassioukov
- 2 Experimental Medicine Program, Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .,3 International Collaboration on Repair Discoveries (ICORD), University of British Columbia , Vancouver, British Columbia, Canada .,4 Department of Physical Medicine and Rehabilitation, University of British Columbia , Vancouver, British Columbia, Canada
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260
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Stöckigt F, Jüngst P, Linhart M, Nickenig G, Andrié R, Beiert T, Schrickel JW. Association of Heart Rate Turbulence With Arrhythmia Susceptibility and Heart Disease in Mice. J Cardiovasc Electrophysiol 2015. [PMID: 26222888 DOI: 10.1111/jce.12766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Recent studies have demonstrated the feasibility of measuring heart rate turbulence (HRT) as a marker of baroreflex function in healthy mice. The aim of this investigation was to measure HRT in a mouse model with induced structural heart defects and to determine if there were threshold values of HRT for inducible ventricular tachycardias (VTs). METHODS AND RESULTS HRT was measured during electrophysiological investigations 2 weeks after transverse aortic constriction (TAC, n = 13) or myocardial cryoinfarction (MCI, n = 14). Sham-operated mice served as controls (n = 8 for TAC controls and n = 9 for MCI controls). Mice with heart disease lacked an early acceleration (turbulence onset [TO]) in heart rate after extrastimulus pacing (heart disease: 0.39% [0.19%-0.59%] vs. all controls: -0.04% [-0.25-0.19%]; P < 0.01). At a cutoff value of >0.25%, TO could be used to classify mice with induced heart disease with a sensitivity of 64.0% and specificity of 88.2% (P < 0.01) but did not identify mice at higher risk of induced VTs. Animals that were susceptible to VTs (n = 8) had lower values for turbulence slope (TS) compared with noninducible mice (6.2 milliseconds/beat [3.1-9.5 milliseconds/beat] vs. 10.1 milliseconds/beat [7.2-14.2 milliseconds/beat]; P = 0.03). TS <7.8 milliseconds/beat identified mice with inducible VTs with a sensitivity of 75.0% and specificity of 75.8% (P = 0.02). CONCLUSION Measurement of HRT is feasible in mouse models with induced structural heart disease. More abnormal values for TO were found in the presence of structural heart disease but did not predict susceptibility to VTs. Decreased TS was associated with VTs induced by programmed stimulation.
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Affiliation(s)
- Florian Stöckigt
- University Hospital Bonn, Department of Medicine-Cardiology, Sigmund Freud, Bonn, Germany
| | - Philipp Jüngst
- University Hospital Bonn, Department of Medicine-Cardiology, Sigmund Freud, Bonn, Germany
| | - Markus Linhart
- University Hospital Bonn, Department of Medicine-Cardiology, Sigmund Freud, Bonn, Germany
| | - Georg Nickenig
- University Hospital Bonn, Department of Medicine-Cardiology, Sigmund Freud, Bonn, Germany
| | - René Andrié
- University Hospital Bonn, Department of Medicine-Cardiology, Sigmund Freud, Bonn, Germany
| | - Thomas Beiert
- University Hospital Bonn, Department of Medicine-Cardiology, Sigmund Freud, Bonn, Germany
| | - Jan Wilko Schrickel
- University Hospital Bonn, Department of Medicine-Cardiology, Sigmund Freud, Bonn, Germany
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261
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Huang WL, Hwang BT, Lai CT, Li JY, Kuo TBJ, Yang CCH. Is Heart Rate Variability Related to Season of Birth? Clin Cardiol 2015. [PMID: 26212374 DOI: 10.1002/clc.22410] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Season of birth (SOB) has been found to be related to cardiovascular mortality, but the mechanisms are unclear. It is suggested that birth in winter is a protective factor for the circulatory system, and this should be able to be observed using heart rate variability (HRV) measurements. The phenomenon may have a sex difference and is likely to be modulated by climatic factors. This study focused on this problem and investigates healthy school-age children to minimize confounding factors. HYPOTHESIS Birth in winter is protective to cardiovascular system via autonomic modulation. There is a gender difference in the relationship between SOB and autonomic activity. Climatic factors are the cause of SOB effects on autonomic system. METHODS A total of 381 healthy school-age children were recruited for this study. Their HRV profiles were measured once and climatic information related to their month of birth was gathered. The HRV profiles of the 2 sexes and 4 seasons of birth were compared. Correlation and regression analysis were performed to clarify the relationship between climatic factors and the HRV results. RESULTS Boys born in winter have higher high-frequency power (HF) but a lower ratio of low-frequency power to high-frequency power (LF/HF) than do males born in other seasons. This result is not found for girls. Age and the temperature of the SOB are predictive factors for HF among boys. The humidity of SOB is a predictive factor for normalized low-frequency power (LF%) and LF/HF among girls. CONCLUSIONS Season of birth is related to both parasympathetic and sympathetic activity among school-age children, especially boys. Temperature and humidity are potential causes of this SOB phenomenon.
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Affiliation(s)
- Wei-Lieh Huang
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Department of Psychiatry, National Taiwan University Hospital, Yun-Lin Branch, Yunlin, Taiwan.,Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Be-Tau Hwang
- Department of Pediatrics, Taipei City Hospital, Taipei, Taiwan
| | - Chun-Ting Lai
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Jia-Yi Li
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Terry B J Kuo
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan.,Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
| | - Cheryl C H Yang
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan.,Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
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262
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Horsman HM, Peebles KC, Tzeng YC. Interactions between breathing rate and low-frequency fluctuations in blood pressure and cardiac intervals. J Appl Physiol (1985) 2015. [PMID: 26205543 DOI: 10.1152/japplphysiol.00525.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Evidence derived from spontaneous measures of cardiovagal baroreflex sensitivity (BRS) suggests that slow breathing at 6 breaths/min augments BRS. However, increases in BRS associated with slow breathing may simply reflect the frequency-dependent nature of the baroreflex rather than the modulation of baroreflex function by changes in breathing rate per se. To test this hypothesis we employed a crossover study design (n = 14) wherein breathing rate and systolic arterial blood pressure (SAP) oscillation induced via the application of oscillating lower body negative pressure (OLBNP) were independently varied at fixed frequencies. Breathing rate was controlled at 6 or 10 breaths/min with the aid of a metronome, and SAP oscillations were driven at 0.06 Hz and 0.1 Hz using OLBNP. The magnitudes of SAP and R-R interval (cardiac period) oscillations were quantified using power spectral analysis, and the transfer function gain between SAP and R-R interval was used to estimate BRS. Linear mixed-effects models were used to examine the main effects and interactions between breathing rate and OLBNP frequency. There was no statistical interaction between breathing and OLBNP frequency (P = 0.59), indicating that the effect of breathing rate on BRS did not differ according to OLBNP frequency (and vice versa). Additionally, there was no main effect for breathing rate (P = 0.28). However, we observed a significant main effect for OLBNP frequency (P = 0.01) consistent with the frequency-dependent nature of baroreflex. These findings suggest that increases in spectral indices of BRS reflect the frequency dependence of the baroreflex and are not due to slow breathing per se.
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Affiliation(s)
- H M Horsman
- Cardiovascular Systems Laboratory and Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - K C Peebles
- Cardiovascular Systems Laboratory and Centre for Translational Physiology, University of Otago, Wellington, New Zealand; Department of Physiology, University of Otago, Dunedin, New Zealand; and Department of Health Professions, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Y C Tzeng
- Cardiovascular Systems Laboratory and Centre for Translational Physiology, University of Otago, Wellington, New Zealand;
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263
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Chalacheva P, Kato RM, Sangkatumvong S, Detterich J, Bush A, Wood JC, Meiselman H, Coates TD, Khoo MCK. Autonomic responses to cold face stimulation in sickle cell disease: a time-varying model analysis. Physiol Rep 2015; 3:3/7/e12463. [PMID: 26177958 PMCID: PMC4552538 DOI: 10.14814/phy2.12463] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 06/24/2015] [Indexed: 11/24/2022] Open
Abstract
Sickle cell disease (SCD) is characterized by sudden onset of painful vaso-occlusive crises (VOC), which occur on top of the underlying chronic blood disorder. The mechanisms that trigger VOC remain elusive, but recent work suggests that autonomic dysfunction may be an important predisposing factor. Heart-rate variability has been employed in previous studies, but the derived indices have provided only limited univariate information about autonomic cardiovascular control in SCD. To circumvent this limitation, a time-varying modeling approach was applied to investigate the functional mechanisms relating blood pressure (BP) and respiration to heart rate and peripheral vascular resistance in healthy controls, untreated SCD subjects and SCD subjects undergoing chronic transfusion therapy. Measurements of respiration, heart rate, continuous noninvasive BP and peripheral vascular resistance were made before, during and after the application of cold face stimulation (CFS), which perturbs both the parasympathetic and sympathetic nervous systems. Cardiac baroreflex sensitivity estimated from the model was found to be impaired in nontransfused SCD subjects, but partially restored in SCD subjects undergoing transfusion therapy. Respiratory-cardiac coupling gain was decreased in SCD and remained unchanged by chronic transfusion. These results are consistent with autonomic dysfunction in the form of impaired parasympathetic control and sympathetic overactivity. As well, CFS led to a significant reduction in vascular resistance baroreflex sensitivity in the nontransfused SCD subjects but not in the other groups. This blunting of the baroreflex control of peripheral vascular resistance during elevated sympathetic drive could be a potential factor contributing to the triggering of VOC in SCD.
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Affiliation(s)
- Patjanaporn Chalacheva
- Department of Biomedical Engineering, Viterbi School of Engineering University of Southern California, Los Angeles, California, USA
| | - Roberta M Kato
- Department of Pediatrics, Children's Hospital of Los Angeles, Los Angeles, California, USA
| | - Suvimol Sangkatumvong
- Department of Biomedical Engineering, Viterbi School of Engineering University of Southern California, Los Angeles, California, USA
| | - Jon Detterich
- Department of Pediatrics, Children's Hospital of Los Angeles, Los Angeles, California, USA
| | - Adam Bush
- Department of Biomedical Engineering, Viterbi School of Engineering University of Southern California, Los Angeles, California, USA
| | - John C Wood
- Department of Pediatrics, Children's Hospital of Los Angeles, Los Angeles, California, USA
| | - Herbert Meiselman
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Thomas D Coates
- Department of Pediatrics, Children's Hospital of Los Angeles, Los Angeles, California, USA
| | - Michael C K Khoo
- Department of Biomedical Engineering, Viterbi School of Engineering University of Southern California, Los Angeles, California, USA
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264
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Pal GK, Chandrasekaran A, Pal P, Nivedita N, Indumathy J, Sirisha A. Prehypertension status, cardiometabolic risks, and decreased baroreflex sensitivity are linked to sympathovagal imbalance in salt-preferring individuals. Clin Exp Hypertens 2015; 37:609-15. [DOI: 10.3109/10641963.2015.1036059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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265
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266
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Ataee P, Hahn JO, Dumont GA, Noubari HA, Boyce WT. A model-based approach to stability analysis of autonomic-cardiac regulation. Comput Biol Med 2015; 61:119-26. [PMID: 25898226 DOI: 10.1016/j.compbiomed.2015.03.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 02/23/2015] [Accepted: 03/16/2015] [Indexed: 10/23/2022]
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267
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Tegeler CH, Shaltout HA, Tegeler CL, Gerdes L, Lee SW. Rightward dominance in temporal high-frequency electrical asymmetry corresponds to higher resting heart rate and lower baroreflex sensitivity in a heterogeneous population. Brain Behav 2015; 5:e00343. [PMID: 26085968 PMCID: PMC4467777 DOI: 10.1002/brb3.343] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 02/27/2015] [Accepted: 03/22/2015] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVE Explore potential use of a temporal lobe electrical asymmetry score to discriminate between sympathetic and parasympathetic tendencies in autonomic cardiovascular regulation. METHODS 131 individuals (82 women, mean age 43.1, range 13-83) with diverse clinical conditions completed inventories for depressive (CES-D or BDI-II) and insomnia-related (ISI) symptomatology, and underwent five-minute recordings of heart rate and blood pressure, allowing calculation of heart rate variability and baroreflex sensitivity (BRS), followed by one-minute, two-channel, eyes-closed scalp recordings of brain electrical activity. A temporal lobe high-frequency (23-36 Hz) electrical asymmetry score was calculated for each subject by subtracting the average amplitude in the left temporal region from amplitude in the right temporal region, and dividing by the lesser of the two. RESULTS Depressive and insomnia-related symptomatology exceeding clinical threshold levels were reported by 48% and 50% of subjects, respectively. Using a cutoff value of 5% or greater to define temporal high-frequency asymmetry, subjects with leftward compared to rightward asymmetry were more likely to report use of a sedative-hypnotic medication (42% vs. 22%, P = 0.02). Among subjects with asymmetry of 5% or greater to 30% or greater, those with rightward compared to leftward temporal high-frequency asymmetry had higher resting heart rate (≥5% asymmetry, 72.3 vs. 63.8, P = 0.004; ≥10%, 71.5 vs. 63.0, P = 0.01; ≥20%, 72.2 vs. 64.2, P = 0.05; ≥30%, 71.4 vs. 64.6, P = 0.05). Subjects with larger degrees of rightward compared to leftward temporal high-frequency asymmetry had lower baroreflex sensitivity (≥40% asymmetry, 10.6 vs. 16.4, P = 0.03; ≥50% asymmetry, 10.4 vs. 16.7, P = 0.05). CONCLUSION In a heterogeneous population, individuals with rightward compared to leftward temporal high-frequency electrical asymmetry had higher resting heart rate and lower BRS. Two-channel recording of brain electrical activity from bilateral temporal regions appears to hold promise for further investigation as a means to assess cortical activity associated with autonomic cardiovascular regulation.
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Affiliation(s)
- Charles H Tegeler
- Department of Neurology, Wake Forest School of Medicine (WFSM) Winston-Salem, North Carolina
| | - Hossam A Shaltout
- Hypertension and Vascular Research Center, Department of Obstetrics and Gynecology, WFSM Winston-Salem, North Carolina
| | - Catherine L Tegeler
- Department of Neurology, Wake Forest School of Medicine (WFSM) Winston-Salem, North Carolina
| | - Lee Gerdes
- Brain State Technologies, LLC Scottsdale, Arizona
| | - Sung W Lee
- Brain State Technologies, LLC Scottsdale, Arizona
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268
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Cao Q, Zhang J, Xu G. Hemodynamic changes and baroreflex sensitivity associated with carotid endarterectomy and carotid artery stenting. INTERVENTIONAL NEUROLOGY 2015; 3:13-21. [PMID: 25999987 DOI: 10.1159/000366231] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Atherosclerotic carotid lesion is a major cause of stroke which accounts for up to 20% of ischemic stroke. Aggressive treatment of carotid stenosis may prevent stroke. Currently, carotid endarterectomy (CEA) and carotid artery stenting (CAS) are the first-line treatments for severe carotid stenosis. CEA is superior to medical therapy in preventing stroke and cardiovascular death. CAS has emerged as an alternative to CEA in recent years due to its less invasive nature. However, both CEA and CAS may be associated with adverse hemodynamic changes as well as a variation of carotid baroreflex sensitivity. There is no consensus on which of these two methods is more advantageous concerning the procedure-related hemodynamic changes. This article reviews the hemodynamic changes and baroreflex sensitivity after CEA and CAS.
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Affiliation(s)
- Qinqin Cao
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Jun Zhang
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Gelin Xu
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
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269
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Lima JW, Hentschke VS, Rossato DD, Quagliotto E, Pinheiro L, Almeida E, Dal Lago P, Lukrafka JL. Chronic electroacupuncture of the ST36 point improves baroreflex function and haemodynamic parameters in heart failure rats. Auton Neurosci 2015; 193:31-7. [PMID: 26032957 DOI: 10.1016/j.autneu.2015.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 04/28/2015] [Accepted: 05/05/2015] [Indexed: 12/20/2022]
Abstract
Electroacupuncture (EA) has been used to treat many diseases, including heart failure (HF). This study aimed to evaluate the effects of chronic stimulation in the ST36 acupuncture point on haemodynamic parameters and baroreflex function in rats with HF. Cardiovascular parameters assessed were heart rate (HR), blood pressure (BP), and the reflex cardiovascular response of HR triggered by stimulation of baroreceptors in animals with HF subsequent to acute myocardial infarction (AMI). Male Wistar rats were divided into three groups: Sham Control - animals without HF and without EA; HF Control group - animals with HF and without EA; and HF EA group - animals with HF that received the EA protocol. Six weeks after surgical induction of AMI, the EA protocol (8 weeks, 5 times a week) was performed. The protocol was applied with EA at the ST36 point, frequency of 2 Hz, pulse of 0.3 ms and intensity of 1-3 mA for 30 min. Haemodynamic parameters and baroreceptor function were assessed. There was no difference between groups in the variables HR, systolic blood pressure (SBP) and diastolic blood pressure (DBP), which were evaluated with awake animals (p>0.05). There was an increase in the mean arterial pressure (MAP) in the HF EA group compared to the HF Control group (p<0.05). The maximum gain of the baroreflex heart rate response (Gain) was higher in the HF EA group than the HF Control and Sham Control groups. Chronic EA in the ST36 point increased the MAP and baroreflex sensitivity in rats with HF.
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Affiliation(s)
- J W Lima
- Physiology Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil
| | - V S Hentschke
- Physiology Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil
| | - D D Rossato
- Physiology Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil; Centro Universitário Franciscano, Brazil
| | - E Quagliotto
- Physiology Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil
| | - L Pinheiro
- Physiology Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil
| | - E Almeida
- Physiology Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil
| | - P Dal Lago
- Physiology Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil; Department of Physical Therapy, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil
| | - J L Lukrafka
- Department of Physical Therapy, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Brazil.
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270
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Thompson M, Thompson L, Reid-Chung A. Treating Postconcussion Syndrome with LORETA Z-Score Neurofeedback and Heart Rate Variability Biofeedback: Neuroanatomical/Neurophysiological Rationale, Methods, and Case Examples. ACTA ACUST UNITED AC 2015. [DOI: 10.5298/1081-5937-43.1.07] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Media attention has highlighted the critical problem of concussion injuries in sport and the challenge of treating and rehabilitating individuals with traumatic brain injury. The authors present a framework for the treatment of traumatic brain injury, using low-resolution electromagnetic tomography Z-score based neurofeedback and heart rate–variability biofeedback. The article advocates a comprehensive assessment process including the use of a 19-channel quantitative electroencephalogram, a heart rate variability baseline, and symptom severity questionnaires for attention deficit/hyperactivity disorder, depression, and anxiety. The initial medical assessment, neuropsychological assessment, and evoked potential studies also have potential for a more precise assessment of deficits in brain activation patterns, which assists the targeting of neurofeedback training.
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Affiliation(s)
- Michael Thompson
- The ADD Centre, Biofeedback Institute of Toronto, Mississauga, Ontario
| | - Lynda Thompson
- The ADD Centre, Biofeedback Institute of Toronto, Mississauga, Ontario
| | - Andrea Reid-Chung
- The ADD Centre, Biofeedback Institute of Toronto, Mississauga, Ontario
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271
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Abstract
OBJECTIVE To evaluate sex differences in left ventricular (LV) function after an ultramarathon, and the association of vascular and training indices with the magnitude of exercise-induced cardiac fatigue. DESIGN Descriptive field study. SETTING Fat Dog 100 Ultramarathon Trail Race, Canada. PARTICIPANTS Thirty-four (13 women) recreational runners (aged 28-56 years). INTERVENTIONS A 100-km or 160-km mountain marathon. MAIN OUTCOME MEASURES Baseline baroreceptor sensitivity, heart rate variability, and arterial compliance; Pre-exercise and postexercise echocardiographic evaluations of LV dimensions, volumes, Doppler flow velocities, tissue velocities, strain, and strain rate. RESULTS Finishers represented 17 men (44.8 ± 6.6 years) and 8 women (45.9 ± 10.2 years; P = 0.758). After ultraendurance exercise, significant reductions (P < 0.05) in fractional shortening (men: 40.9 ± 6.9 to 34.1 ± 7.6%; women: 42.5 ± 6.5 to 34.6 ± 7.9%) diastolic filling (E/A, men: 1.28 ± 0.68 to 1.26 ± 0.33; women: 1.55 ± 0.51 to 1.30 ± 0.27), septal and lateral tissue velocities (E'), and longitudinal strain (men: -21.02 ± 1.98 to -18.44 ± 0.34; women: -20.28 ± 1.90 to -18.44 ± 2.34) were observed. Sex differences were found for baseline cardiac structure and global function, peak late transmitral flow velocity, and estimates of LV filling pressures (P < 0.05). Regression analysis found that higher baseline arterial compliance was associated with lower reductions in cardiac function postexercise, to which sex was a significant factor for E' of the lateral wall. Faster race pace and greater lifetime ultramarathons were associated with lower reductions in LV longitudinal strain (P < 0.05). CONCLUSIONS Cardiac responses after an ultramarathon were similar between men and women. Greater evidence of exercise-induced cardiac fatigue was found to be associated with lower baseline arterial compliance and training status/experience. CLINICAL RELEVANCE These findings suggest that vascular health is an important contributor to the degree of cardiovascular strain incurred as the result of an acute bout of prolonged strenuous exercise.
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272
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Onizuka C, Niimi Y, Sato M, Sugenoya J. Arterial blood pressure response to head-up tilt test and orthostatic tolerance in nurses. Environ Health Prev Med 2015; 20:262-70. [PMID: 25894388 DOI: 10.1007/s12199-015-0455-5] [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: 03/02/2015] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES High tolerance to postural changes was examined in nurses. METHODS Twelve female nurses and 12 healthy controls underwent a 70° head-up tilt (HUT) test for 10 min. Blood pressure (BP), heart rate (HR), pulse pressure, and hormone levels were measured. Baroreceptor sensitivity (BRS) was calculated using a sequence technique. RESULTS HR increased during HUT in both subject groups, with no difference between groups. Systolic BP was rapidly increased by HUT in both subject groups, and was higher in the nurse group than in the control group during the first 2 min of HUT. Pulse pressure decreased during 1-2.5 min of HUT in the control group, but there was no decrease in the nurse group. BRS was decreased by HUT in the nurse group, while it tended to be decreased in the control group. Both during baseline and HUT, BRS was lower in the nurse group than in the control group. Plasma noradrenaline increased with HUT, and the increase was greater in the nurse group than in the control group. CONCLUSIONS Although nurse subjects had a lower BRS during HUT than control subjects, they were able to effectively maintain BP during HUT, suggesting that nurse subjects had higher orthostatic tolerance. The better maintenance of BP in nurse subjects appeared to be associated with a compensatory mechanism other than the arterial baroreflex and/or a hemodynamic mechanism.
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Affiliation(s)
- Chisato Onizuka
- Department of Physiology, Aichi Medical University, Nagakute, Aichi, 480-1195, Japan,
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273
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Périard D, Beqiraj B, Hayoz D, Viswanathan B, Evans K, Thurston SW, Davidson PW, Myers GJ, Bovet P. Associations of baroreflex sensitivity, heart rate variability, and initial orthostatic hypotension with prenatal and recent postnatal methylmercury exposure in the Seychelles Child Development Study at age 19 years. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:3395-405. [PMID: 25807149 PMCID: PMC4377973 DOI: 10.3390/ijerph120303395] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 03/11/2015] [Accepted: 03/13/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND A few studies have suggested an association between prenatal exposure to methylmercury and decreased heart rate variability (HRV) related to autonomic heart function, but no study has examined this association using baroreflex sensitivity (BRS). In this study we assessed the distribution of BRS and immediate orthostatic hypotension (IOH) in young Seychellois adults and their associations with exposure to prenatal and recent postnatal methylmercury. METHODS Subjects in the Seychelles Child Development Study (SCDS) main cohort were evaluated at age 19 years. Non-invasive beat-to-beat blood pressure (BP) monitoring (Finapres, Ohmeda) was performed at rest and during active standing in 95 consecutive subjects. Recent postnatal mercury exposure was measured in subjects' hair at the age of 19 years and prenatal exposure in maternal hair grown during pregnancy. BRS was estimated by sequence analysis to identify spontaneous ascending and descending BP ramps. HRV was estimated by the following markers: PNN50 (relative numbers of normal-to-normal intervals which are shorter by more than 50 ms than the immediately following normal-to-normal intervals); rMSSD (root mean of the squared sum of successive interval differences); LF/HF (low frequency/high frequency component ratio); ratio of the mean expiratory/inspiratory RR intervals (EI ratio); and the ratio between the longest RR interval 30 s after active standing and the shortest RR interval at 15 s (Max30/Min15). IOH was estimated by the deepest BP fall within the first 15 s after active standing up. RESULTS Prenatal MeHg exposures were similar in boys and girls (6.7±4.3, 6.7±3.8 ng/g) but recent postnatal mercury levels were higher in males than females (11.2±5.8 vs 7.9±4.3 ng/g, p=0.003). Markers of autonomic heart rate control were within the normal range (BRS: 24.8±7 ms/mm Hg, PNN50: 24.9±6.8%, rMSSD: 68±22, LF/HF: 0.61±0.28) in both sexes. After standing, 51.4% of subjects had a transient systolic BP drop>40 mm Hg, but only 5.3% reported dizziness or had syncope. Prenatal and recent postnatal MeHg levels, overall, were not associated with BRS, E/I ratio, PNN50, rMSSD, LF/HF ratio, Max30/Min15 ratio, and IOH. CONCLUSIONS This study provides no support for the hypothesis that prenatal or recent postnatal MeHg exposure from fish consumption is associated with impaired autonomic heart rate control.
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Affiliation(s)
- Daniel Périard
- Service d'Angiologie, Hôpital Cantonal, Fribourg 1700, Switzerland.
| | - Bujar Beqiraj
- Service d'Angiologie, Hôpital Cantonal, Fribourg 1700, Switzerland.
| | - Daniel Hayoz
- Service d'Angiologie, Hôpital Cantonal, Fribourg 1700, Switzerland.
| | | | - Katie Evans
- Department of Biostatistics, University of Rochester, Rochester, NY 14642, USA.
| | - Sally W Thurston
- Department of Biostatistics, University of Rochester, Rochester, NY 14642, USA.
| | - Philip W Davidson
- Department of Pediatrics, University of Rochester, Rochester, NY 14642, USA.
| | - Gary J Myers
- Department of Pediatrics, University of Rochester, Rochester, NY 14642, USA.
- Institute of Social and Preventive Medicine, Lausanne University Hospital, CHUV, Lausanne 1010, Switzerland.
| | - Pascal Bovet
- Section of Non Communicable Diseases, Ministry of Health, Victoria, Seychelles.
- Institute of Social and Preventive Medicine, Lausanne University Hospital, CHUV, Lausanne 1010, Switzerland.
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274
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Pinna GD, Maestri R, La Rovere MT. Assessment of baroreflex sensitivity from spontaneous oscillations of blood pressure and heart rate: proven clinical value? Physiol Meas 2015; 36:741-53. [PMID: 25798657 DOI: 10.1088/0967-3334/36/4/741] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The baroreceptor-heart rate reflex (baroreflex sensitivity, BRS) is a key mechanism contributing to the neural regulation of the cardiovascular system. Several methods have been proposed so far to assess BRS by analyzing the spontaneous beat-to-beat fluctuations of arterial blood pressure and heart rate. These methods are inherently simple, non-invasive and low-cost. This study is an attempt to address the question of whether spontaneous baroreflex methods have proven to be of value in the clinical setting. In the first part of this article, we critically review most representative clinical studies using spontaneous BRS techniques either for risk stratification or treatment evaluation, these being major issues in the clinical management of the patients. In the second part, we address two important aspects of spontaneous BRS measurements: measurability and reliability. Estimation of BRS in the studies selected for the review was performed according to the sequence, transfer function, alpha-index and phase-rectified signal averaging method. Arterial blood pressure was recorded non-invasively during supine, short-term (<30 min) laboratory recordings. The conclusion from this review is that spontaneous BRS techniques have been shown to be of great value in clinical practice but further work is needed to confirm the validity of previous findings and to widen the field of clinical applications. Measurability and reliability can be a major issue in the measurement of spontaneous BRS, particularly in some patient populations like post-myocardial infarction and heart failure patents. Main causes of poor measurability are: non-sinus rhythm, a high rate of ectopic beats and the need for recorded time series of RR interval and arterial blood pressure to satisfy the constraints of the different BRS estimation algorithms. As for reliability, within-subject variability is rather high in the measurements of spontaneous BRS and, therefore, should be carefully taken into account when BRS measurements are used to detect treatment effects in individual patients.
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Affiliation(s)
- Gian Domenico Pinna
- Department of Biomedical Engineering, Fondazione S. Maugeri-IRCCS, Montescano, Italy
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275
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Fyfe KL, Yiallourou SR, Wong FY, Odoi A, Walker AM, Horne RSC. Gestational age at birth affects maturation of baroreflex control. J Pediatr 2015; 166:559-65. [PMID: 25556016 DOI: 10.1016/j.jpeds.2014.11.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/29/2014] [Accepted: 11/11/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To assess the effect of prone sleeping, the major risk factor for sudden infant death syndrome, in the control of blood pressure (BP) in preterm infants born across a range of gestational ages. STUDY DESIGN Daytime polysomnography was performed at 2-4 weeks, 2-3 months, and 5-6 months postterm age. The participants were 21 very preterm (mean gestation 29.4 ± 0.3 weeks), 14 preterm (mean gestation 33.1 ± 0.3 weeks), and 17 term (mean gestation 40.1 ± 0.3 weeks). BP was measured via a Finometer cuff (Finapres Medical Systems, Amsterdam, The Netherlands) placed around the wrist. Data were recorded both supine and prone. Baroreflex sensitivity (BRS) was calculated via cross-spectral analysis of spontaneous fluctuations in BP. RESULTS BRS was lower in the prone position in very preterm infants at 2-4 weeks in active sleep (P < .05). Maturation of BRS was delayed in very preterm compared with both preterm and term infants. CONCLUSIONS Maturation of BRS after term-equivalent age is altered in very preterm infants. Reduced BRS may result in an impaired ability of very preterm infants to respond to cardiovascular stress during infancy and may predispose them to cardiovascular disease later in life.
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Affiliation(s)
- Karinna L Fyfe
- The Ritchie Centre, Monash Institute of Medical Research and Prince Henry's Institute and Monash University, Melbourne, Victoria, Australia; The Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Stephanie R Yiallourou
- The Ritchie Centre, Monash Institute of Medical Research and Prince Henry's Institute and Monash University, Melbourne, Victoria, Australia; The Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Flora Y Wong
- The Ritchie Centre, Monash Institute of Medical Research and Prince Henry's Institute and Monash University, Melbourne, Victoria, Australia; The Department of Paediatrics, Monash University, Melbourne, Victoria, Australia; Monash Newborn, Monash Health, Melbourne, Victoria, Australia
| | - Alexsandria Odoi
- The Ritchie Centre, Monash Institute of Medical Research and Prince Henry's Institute and Monash University, Melbourne, Victoria, Australia
| | - Adrian M Walker
- The Ritchie Centre, Monash Institute of Medical Research and Prince Henry's Institute and Monash University, Melbourne, Victoria, Australia
| | - Rosemary S C Horne
- The Ritchie Centre, Monash Institute of Medical Research and Prince Henry's Institute and Monash University, Melbourne, Victoria, Australia; The Department of Paediatrics, Monash University, Melbourne, Victoria, Australia.
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276
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Effects of gravitational acceleration on cardiovascular autonomic control in resting humans. Eur J Appl Physiol 2015; 115:1417-27. [DOI: 10.1007/s00421-015-3117-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 01/26/2015] [Indexed: 10/24/2022]
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277
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Saint Martin M, Roche F, Thomas-Anterion C, Barthélémy JC, Sforza E. Eight-year parallel change in baroreflex sensitivity and memory function in a sample of healthy older adults. J Am Geriatr Soc 2015; 63:270-5. [PMID: 25641086 DOI: 10.1111/jgs.13252] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To examine whether changes in the cardiac autonomic nervous system (ANS) over time, as expressed by baroreflex sensitivity (BRS), were associated with long-term changes in cognitive performance in elderly individuals without dementia. DESIGN Community-based 8-year longitudinal study. SETTING Clinical settings. PARTICIPANTS Individuals aged 66.9 ± 0.9 (N = 425). MEASUREMENTS At baseline and follow-up, subjects underwent a clinical interview, autonomic and vascular measurements, and a neuropsychological evaluation including attentional, executive, and memory tests using standardized Z-scores. BRS was defined as being normal, moderate, or severe alteration at each evaluation. On the basis of the longitudinal changes subjects were stratified as being stable, moderate or improved. RESULTS Mean attentional, executive, and memory change Z-scores were -0.41 ± 0.9, -0.15 ± 0.7, and -0.14 ± 0.8, respectively. BRS of 56% of the subjects remained unchanged, of 20% decreased, and of 24% improved. After regression analysis, the worsened BRS group was 1.88 times as likely to have greater memory change as the group with stable BRS (P = .02). No significant association was found between longitudinal change in BRS and attentional and executive changes. CONCLUSION In healthy elderly individuals, BRS decrease was associated with a weak but significant decrease in memory function. The long-term effect of BRS on memory changes may suggest a role of the ANS in cognitive decline.
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Affiliation(s)
- Magali Saint Martin
- Département de Physiologie Clinique et de l'exercice, Pôle Neuro-Ostéo Locomoteur, Centre Hospitalo-Universitaire, Faculté de Mèdecine de Saint-Etienne, Université Jean Moulin, Saint-Etienne, France; pôle de Recherche et d'Enseignement Supérieur, Université de Lyon, Lyon, France; Laboratoire d'Etude des Mécanismes Cognitifs, University of Lyon 2, Lyon, France
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Lau KD, Figueroa CA. Simulation of short-term pressure regulation during the tilt test in a coupled 3D-0D closed-loop model of the circulation. Biomech Model Mechanobiol 2015; 14:915-29. [PMID: 25567754 PMCID: PMC4490186 DOI: 10.1007/s10237-014-0645-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/19/2014] [Indexed: 11/30/2022]
Abstract
Short-term fluctuations in arterial pressures arising from normal physiological function are buffered by a negative feedback system known as the arterial baroreflex. Initiated by altered biomechanical stretch in the vessel wall, the baroreflex coordinates a systemic response that alters heart rate, cardiac contractility and peripheral vessel vasoconstriction. In this work, a coupled 3D–0D formulation for the short-term pressure regulation of the systemic circulation is presented. Including the baroreflex feedback mechanisms, a patient-specific model of the large arteries is subjected to a simulated head up tilt test. Comparative simulations with and without baroreflex control highlight the critical role that the baroreflex has in regulating variations in pressures within the systemic circulation.
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Affiliation(s)
- Kevin D. Lau
- Department of Biomedical Engineering, King’s College London, London, SE1 7EH UK
| | - C. Alberto Figueroa
- Department of Biomedical Engineering, King’s College London, London, SE1 7EH UK
- Departments of Surgery and Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
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279
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Almeida J, Duarte JO, Oliveira LA, Crestani CC. Effects of nitric oxide synthesis inhibitor or fluoxetine treatment on depression-like state and cardiovascular changes induced by chronic variable stress in rats. Stress 2015; 18:462-74. [PMID: 26068517 DOI: 10.3109/10253890.2015.1038993] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Comorbidity between mood disorders and cardiovascular disease has been described extensively. However, available antidepressants can have cardiovascular side effects. Treatment with selective inhibitors of neuronal nitric oxide synthase (nNOS) induces antidepressant effects, but whether the antidepressant-like effects of these drugs are followed by cardiovascular changes has not been previously investigated. Here, we tested in male rats exposed to chronic variable stress (CVS) the hypothesis that nNOS blockers are advantageous compared with conventional antidepressants in terms of cardiovascular side effects. We compared the effects of chronic treatment with the preferential nNOS inhibitor 7-nitroindazole (7-NI) with those evoked by the conventional antidepressant fluoxetine on alterations that are considered as markers of depression (immobility in the forced swimming test, FST, decreased body weight gain and increased plasma corticosterone concentration) and cardiovascular changes caused by CVS. Rats were exposed to a 14-day CVS protocol, while being concurrently treated daily with either 7-NI (30 mg/kg) or fluoxetine (10 mg/kg). Fluoxetine and 7-NI prevented the increase in immobility in the FST induced by CVS and reduced plasma corticosterone concentration in stressed rats. Both these treatments also prevented the CVS-evoked reduction of the depressor response to vasodilator agents and baroreflex changes. Fluoxetine and 7-NI-induced cardiovascular changes independent of stress exposure, including cardiac autonomic imbalance, increased intrinsic heart rate and vascular sympathetic modulation, a reduction of the pressor response to vasoconstrictor agents, and impairment of baroreflex activity. Altogether, these findings provide evidence that fluoxetine and 7-NI have similar effects on the depression-like state induced by CVS and on cardiovascular function.
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Affiliation(s)
- Jeferson Almeida
- a Laboratory of Pharmacology , School of Pharmaceutical Sciences, São Paulo State University , UNESP, Araraquara, SP , Brazil and
- b Joint UFSCar-UNESP Graduate Program in Physiological Sciences , São Carlos, SP , Brazil
| | - Josiane O Duarte
- a Laboratory of Pharmacology , School of Pharmaceutical Sciences, São Paulo State University , UNESP, Araraquara, SP , Brazil and
- b Joint UFSCar-UNESP Graduate Program in Physiological Sciences , São Carlos, SP , Brazil
| | - Leandro A Oliveira
- a Laboratory of Pharmacology , School of Pharmaceutical Sciences, São Paulo State University , UNESP, Araraquara, SP , Brazil and
- b Joint UFSCar-UNESP Graduate Program in Physiological Sciences , São Carlos, SP , Brazil
| | - Carlos C Crestani
- a Laboratory of Pharmacology , School of Pharmaceutical Sciences, São Paulo State University , UNESP, Araraquara, SP , Brazil and
- b Joint UFSCar-UNESP Graduate Program in Physiological Sciences , São Carlos, SP , Brazil
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280
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Kuehl LK, Deuter CE, Richter S, Schulz A, Rüddel H, Schächinger H. Two separable mechanisms are responsible for mental stress effects on high frequency heart rate variability: an intra-individual approach in a healthy and a diabetic sample. Int J Psychophysiol 2014; 95:299-303. [PMID: 25500224 DOI: 10.1016/j.ijpsycho.2014.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/27/2014] [Accepted: 12/05/2014] [Indexed: 12/30/2022]
Abstract
Central withdrawal of parasympathetic cardiac control and increased respiratory frequency represent two important determinants of reduced respiratory-related heart rate variability (HRV). However, studies are missing to disentangle their relative contribution during mental stress. Healthy subjects (n=10) and type 2 diabetic patients (n=8), the latter with evidence of cardiac autonomic neuropathy, participated in this study. Using an intra-individual approach, high-frequency (hf) HRV was assessed for spontaneous (during rest and mental stress) and paced breathing (0.15, 0.2, 0.25, 0.3, 0.35, 0.4 and 0.45 Hz; randomized sequence). Mental stress was induced by a challenging reaction time task. Effects of respiratory frequency on hf HRV were individually predicted by paced breathing data. Mental stress decreased hf HRV (p<.001), and increased respiratory frequency (p=.01). Individual prediction of hf HRV by stress respiratory frequency resulted in lower values (p=.02) than observed during rest, indicating that respiratory stress effects were sufficient to reduce hf HRV. However, observed hf HRV values during stress were even lower (p<.001). These results indicate that hf HRV reductions during stress can only partly be explained by concomitant respiratory frequency changes. This effect is detectable in healthy subjects and in patients with evidence of diabetic cardiac autonomic neuropathy.
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Affiliation(s)
- Linn K Kuehl
- Department of Psychiatry and Psychotherapy, Charité University Medical School Berlin, Campus Benjamin Franklin, Eschenallee 3, 14050 Berlin, Germany.
| | - Christian E Deuter
- Department of Psychiatry and Psychotherapy, Charité University Medical School Berlin, Campus Benjamin Franklin, Eschenallee 3, 14050 Berlin, Germany; Department of Clinical Psychophysiology, Institute of Psychobiology, University of Trier, Johanniterufer 15, 54290 Trier, Germany.
| | - Steffen Richter
- Department of Psychiatry and Psychotherapy, Charité University Medical School Berlin, Campus Benjamin Franklin, Eschenallee 3, 14050 Berlin, Germany.
| | - André Schulz
- Institute for Health and Behaviour, Research Unit INSIDE, University of Luxembourg, Route de Diekirch, L-7220 Walferdange, Luxembourg.
| | - Heinz Rüddel
- University of Trier, Centre for Psychobiological and Psychosomatic Research, Department of Behavioral Medicine, St. Franziska Stift, Franziska-Puricelli-Str. 3, 55543 Bad Kreuznach, Germany.
| | - Hartmut Schächinger
- Department of Clinical Psychophysiology, Institute of Psychobiology, University of Trier, Johanniterufer 15, 54290 Trier, Germany.
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281
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Horsman HM, Tzeng YC, Galletly DC, Peebles KC. The repeated sit-to-stand maneuver is a superior method for cardiac baroreflex assessment: a comparison with the modified Oxford method and Valsalva maneuver. Am J Physiol Regul Integr Comp Physiol 2014; 307:R1345-52. [DOI: 10.1152/ajpregu.00376.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Baroreflex assessment has diagnostic and prognostic utility in the clinical and research environments, and there is a need for a reliable, simple, noninvasive method of assessment. The repeated sit-to-stand method induces oscillatory changes in blood pressure (BP) at a desired frequency and is suitable for assessing dynamic baroreflex sensitivity (BRS). However, little is known about the reliability of this method and its ability to discern fundamental properties of the baroreflex. In this study we sought to: 1) evaluate the reliability of the sit-to-stand method for assessing BRS and compare its performance against two established methods (Oxford method and Valsalva maneuver), and 2) examine whether the frequency of the sit-to-stand method influences hysteresis. Sixteen healthy participants underwent three trials of each method. For the sit-to-stand method, which was performed at 0.1 and 0.05 Hz, BRS was quantified as an integrated response (BRSINT) and in response to falling and rising BP (BRSDOWN and BRSUP, respectively). Test retest reliability was assessed using the intraclass correlation coefficient (ICC). Irrespective of frequency, the ICC for BRSINT during the sit-to-stand method was ≥0.88. The ICC for a rising BP evoked by phenylephrine (PEGAIN) in the Oxford method was 0.78 and ≤0.5 for the remaining measures. During the sit-to-stand method, hysteresis was apparent in all participants at 0.1 Hz but was absent at 0.05 Hz. These findings indicate the sit-to-stand method is a statistically reliable BRS assessment tool and suitable for the examination of baroreflex hysteresis. Using this approach we showed that baroreflex hysteresis is a frequency-dependent phenomenon.
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Affiliation(s)
- H. M. Horsman
- Cardiovascular Systems Laboratory
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - Y. C. Tzeng
- Cardiovascular Systems Laboratory
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - D. C. Galletly
- Cardiovascular Systems Laboratory
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - K. C. Peebles
- Cardiovascular Systems Laboratory
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
- Department of Physiology, University of Otago, Dunedin, New Zealand; and
- Department of Human Sciences, Macquarie University, Sydney, Australia
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282
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Smits MM, Muskiet MHA, Tushuizen ME, Kwa KAA, Karemaker JM, van Raalte DH, Diamant M. Uncomplicated human type 2 diabetes is associated with meal-induced blood pressure lowering and cardiac output increase. Diabetes Res Clin Pract 2014; 106:617-26. [PMID: 25458327 DOI: 10.1016/j.diabres.2014.09.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/11/2014] [Accepted: 09/15/2014] [Indexed: 01/18/2023]
Abstract
AIMS Since many type 2 diabetes patients experience postprandial hypotension, the aim of this study was to unravel meal-related changes in systemic hemodynamics and autonomic nervous system (ANS)-balance. METHODS Forty-two age-matched males (15 type 2 diabetes; 12 metabolic syndrome; 15 controls) without overt autonomic neuropathy received a standardized high-fat mixed meal after an overnight fast. Hemodynamic variables were measured by finger plethysmography. Fourier analysis was used to calculate the low-/high-frequency (LF/HF)-ratio, a marker of autonomic nervous system-balance, and baroreceptor reflex sensitivity (BRS). RESULTS Following the meal, diastolic blood pressure (DBP) decreased in type 2 diabetes patients only, paralleled by a significant decrement in systemic vascular resistance (SVR) and an increase in cardiac index. All groups showed an increase in postprandial heart rate. Controls, but not metabolic syndrome or type 2 diabetes patients, showed a meal-related increase in LF/HF-ratio. When combining all study subjects, homeostatic model assessment-insulin resistance (HOMA-IR) was inversely correlated with changes in DBP, SVR, LF/HF-ratio and BRS. CONCLUSIONS Based on these data, we hypothesize that in patients with uncomplicated type 2 diabetes, insulin resistance hampers adequate meal-induced sympathetic activation, leading to a decrease in SVR and resulting in a postprandial drop in DBP.
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Affiliation(s)
- Mark M Smits
- Diabetes Center/Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands.
| | - Marcel H A Muskiet
- Diabetes Center/Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Maarten E Tushuizen
- Diabetes Center/Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Kelly A A Kwa
- Diabetes Center/Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - John M Karemaker
- Department of Systems Physiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Daniël H van Raalte
- Diabetes Center/Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Michaela Diamant
- Diabetes Center/Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
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283
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Age-related reflex responses from peripheral and central chemoreceptors in healthy men. Clin Auton Res 2014; 24:285-96. [PMID: 25421997 PMCID: PMC4256521 DOI: 10.1007/s10286-014-0263-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 10/27/2014] [Indexed: 12/11/2022]
Abstract
Objective The study aimed: (i) to characterize reflex responses from peripheral and central chemoreceptors in different age groups of healthy men (<50 years old vs ≥50 years old) and, (ii) to assess, within these groups, whether there is any relationship between ventilatory and hemodynamic responses from chemoreceptors and indices of autonomic nervous system (ANS). Methods Peripheral chemoreflex sensitivity was assessed by the transient hypoxia method and respiratory, heart rate (HR) and blood pressure responses were calculated. Central chemoreflex sensitivity was assessed by the rebreathing method and respiratory response was calculated. ANS was assessed using heart rate variability indices and baroreflex sensitivity (BRS). Results Sixty-seven healthy men were divided into 2 groups: <50 years (n = 38, mean age: 32 ± 10 years) and ≥50 years (n = 29, mean age: 61 ± 8 years). There were no differences in respiratory response from central and peripheral chemoreceptors between the older and younger groups of healthy males. We found a significantly different pattern of hemodynamic responses from peripheral chemoreceptors between the older and the younger groups. The former expressed attenuated HR acceleration and exaggerated blood pressure increase in response to transient hypoxia. Blunted HR response was related to reduced BRS and sympathovagal imbalance characterized by reduced vagal tone. Blood pressure responses seemed to be independent of sympathovagal balance and BRS. Interpretation Ageing impacts hemodynamic rather than respiratory response from chemoreceptors. Impaired arterial baroreflex and sympathovagal imbalance related to ageing may contribute to decreased heart rate response, but not to increased blood pressure response from peripheral chemoreceptors.
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284
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Carotid interventions and blood pressure. Wien Med Wochenschr 2014; 164:503-7. [DOI: 10.1007/s10354-014-0327-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/21/2014] [Indexed: 10/24/2022]
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285
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Haigney M, Zareba W, La Rovere MT, Grasso I, Mortara D. Assessing the interaction of respiration and heart rate in heart failure and controls using ambulatory Holter recordings. J Electrocardiol 2014; 47:831-5. [PMID: 25172186 DOI: 10.1016/j.jelectrocard.2014.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Mark Haigney
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
| | | | - Maria Teresa La Rovere
- S. Maugeri Foundation, IRCCS, Scientific Institute of Montescano, Montescano, Pavia, Italy
| | - Ian Grasso
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - David Mortara
- University of California San Francisco, San Francisco, CA, USA
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286
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A single exposure to acrolein desensitizes baroreflex responsiveness and increases cardiac arrhythmias in normotensive and hypertensive rats. Cardiovasc Toxicol 2014; 14:52-63. [PMID: 24078368 DOI: 10.1007/s12012-013-9228-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Short-term exposure to air pollutants has been linked to acute cardiovascular morbidity and mortality. Even in the absence of overt signs or symptoms, pollutants can cause subtle disruptions to internal compensatory mechanisms, which maintain homeostatic balance in response to various environmental and physiological stressors. We hypothesized that a single exposure to acrolein, a ubiquitous gaseous air pollutant, would decrease the sensitivity of baroreflex (BRS), which maintains blood pressure by altering heart rate (HR), modify cardiac electrophysiological properties and increase arrhythmia in rats. Wistar-Kyoto normotensive (WKY) and spontaneously hypertensive (SH) rats implanted with radiotelemeters and a chronic jugular vein catheter were tested for BRS using phenylephrine and sodium nitroprusside 2 days before and 1 h after whole-body exposure to 3 ppm acrolein (3 h). HR and electrocardiogram (ECG) were continuously monitored for the detection of arrhythmia in the pre-exposure, exposure and post-exposure periods. Whole-body plethysmography was used to continuously monitor ventilation in conscious animals. SH rats had higher blood pressure, lower BRS and increased frequency of AV block as evidence by non-conducted p-waves when compared with WKY rats. A single exposure to acrolein caused a decrease in BRS and increased incidence of arrhythmia in both WKY and SH rats. There were minimal ECG differences between the strains, whereas only SH rats experienced irregular breathing during acrolein. These results demonstrate that acrolein causes immediate cardiovascular reflexive dysfunction and persistent arrhythmia in both normal and hypertensive animals. As such, homeostatic imbalance may be one mechanism by which air pollution increases risk 24 h after exposure, particularly in people with underlying cardiovascular disease.
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287
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Chu CP, Cui BR, Kannan H, Qiu DL. Alterations in the baroreceptor-heart rate reflex in conscious inbred polydipsic (STR/N) mice. Physiol Res 2014; 64:173-82. [PMID: 25317689 DOI: 10.33549/physiolres.932820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
STR/N is an inbred strain of mice which is known to exhibit extreme polydipsia and polyuria. We previously found central administration of angiotensin II enhanced cardiovascular responses in STR/N mice than normal mice, suggesting that STR/N mice might exhibit different cardiovascular responses. Therefore, in this study, we investigated daily mean arterial blood pressure and heart rate, and changes in the baroreceptor-heart rate reflex in conscious STR/N mice and control (ICR) mice. We found that variability in daily mean arterial blood pressure and heart rate was significantly larger in STR/N mice than in ICR mice (p<0.05). There was a stronger response to phenylephrine (PE) in STR/N mice than in ICR mice. For baroreceptor reflex sensitivity, in the rapid response period, the slopes of PE and sodium nitroprusside (SNP) were more negative in STR/N mice than in ICR mice. In the later period, the slopes of PE and SNP were negatively correlated between heart rate and blood pressure in ICR mice, but their slopes were positively correlated in STR/N mice. These results indicated that STR/N mice exhibited the different cardiovascular responses than ICR mice, suggesting that the dysfunction of baroreceptor reflex happened in conscious STR/N mice.
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Affiliation(s)
- C P Chu
- Cellular Function Research Center, Yanbian University, Yanji City, Jilin Province, China. ;
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288
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Myocardial damage in a mitochondrial myopathy patient with increased ergoreceptor sensitivity and sympatho-vagal imbalance. Int J Cardiol 2014; 176:1396-8. [DOI: 10.1016/j.ijcard.2014.08.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 08/02/2014] [Indexed: 11/22/2022]
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289
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Arnold AC, Diz DI. Endogenous leptin contributes to baroreflex suppression within the solitary tract nucleus of aged rats. Am J Physiol Heart Circ Physiol 2014; 307:H1539-46. [PMID: 25260611 DOI: 10.1152/ajpheart.00282.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The decline in cardiovagal baroreflex function that occurs with aging is accompanied by an increase in circulating leptin levels. Our previous studies showed that exogenous leptin impairs the baroreflex sensitivity for control of heart rate in younger rats, but the contribution of this hormone to baroreflex dysfunction during aging is unknown. Thus we assessed the effect of bilateral leptin microinjection (500 fmol/60 nl) within the solitary tract nucleus (NTS) on the baroreflex sensitivity in older (66 ± 2 wk of age) urethane/chloralose anesthetized Sprague-Dawley rats with elevated circulating leptin levels. In contrast to the 63% reduction observed in younger rats, leptin did not alter the baroreflex sensitivity for bradycardia evoked by phenylephrine in older rats (0.76 ± 0.19 baseline vs. 0.71 ± 0.15 ms/mmHg after leptin; P = 0.806). We hypothesized that this loss of sensitivity reflected endogenous suppression of the baroreflex by elevated leptin, rather than cardiovascular resistance to the peptide. Indeed, NTS administration of a leptin receptor antagonist (75 pmol/120 nl) improved the baroreflex sensitivity for bradycardia in older rats (0.73 ± 0.13 baseline vs. 1.19 ± 0.26 at 10 min vs. 1.87 ± 0.32 at 60 min vs. 1.22 ± 0.54 ms/mmHg at 120 min; P = 0.002), with no effect in younger rats. There was no effect of the leptin antagonist on the baroreflex sensitivity for tachycardia, responses to cardiac vagal chemosensitive fiber activation, or resting hemodynamics in older rats. These findings suggest that the actions of endogenous leptin within the NTS, either produced locally or derived from the circulation, contribute to baroreflex suppression during aging.
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Affiliation(s)
- Amy C Arnold
- Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Debra I Diz
- Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina
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290
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Cote AT, Bredin SSD, Phillips AA, Koehle MS, Warburton DER. Greater autonomic modulation during post-exercise hypotension following high-intensity interval exercise in endurance-trained men and women. Eur J Appl Physiol 2014; 115:81-9. [PMID: 25208772 DOI: 10.1007/s00421-014-2996-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 09/01/2014] [Indexed: 01/03/2023]
Abstract
PURPOSE An acute reduction in blood pressure observed after a single bout of exercise is termed post-exercise hypotension (PEH). In contrast to moderate intensity aerobic exercise, little is known about the PEH response following high-intensity interval exercise. The present purpose is to assess how sex and training status impact PEH following high-intensity interval exercise. METHODS Cardiac volumes and function via echocardiography were measured in 40 normotensive, endurance-trained (ET) and normally active (NA) men and women (Age ± SD = 30.5 ± 5.7) following high-intensity interval cycle exercise. Continuous measurements of ECG and beat-by-beat blood pressure were collected before and 30 min post-exercise for determination of cardiovagal baroreflex function (BRS and αLF), spectral analysis of heart rate and systolic blood pressure (SBP LF). RESULTS Post-exercise systolic BP was significantly reduced from baseline, occurring to a greater degree in ET compared with NA (-12.9 vs. -5.3 mmHg, P = 0.008), while mean arterial pressure was similarly reduced in all groups (-4.6 mmHg, P = 0.003). Despite reduced SVI and TPRI, CI was increased post-exercise (P < 0.01). ET experienced a greater decrease in αLF (P = 0.037) and increase in SBP LF (P = 0.017) than NA. Lean body mass was a significant predictor of change in SBP LF (Std. β = 0.735, P = 0.008). CONCLUSIONS These results characterize greater depressions in cardiovagal baroreflex function, and increased sympathetic activity, following vigorous exercise in endurance-trained individuals compared with normally active participants. This heightened sympathovagal balance after high-intensity exercise may be a compensatory mechanism in response to greater peripheral blood flow demands following vigorous exercise.
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Affiliation(s)
- Anita T Cote
- Cardiovascular Physiology and Rehabilitation Laboratory, University of British Columbia, Rm. 205, Unit II Osborne Centre, 6108 Thunderbird Blvd, Vancouver, BC, V6T 1Z3, Canada,
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291
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Shinohara T, Ebata Y, Ayabe R, Fukui A, Okada N, Yufu K, Nakagawa M, Takahashi N. Cardiac autonomic dysfunction in patients with head-up tilt test-induced vasovagal syncope. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2014; 37:1694-701. [PMID: 25139789 DOI: 10.1111/pace.12484] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 06/09/2014] [Accepted: 06/11/2014] [Indexed: 12/01/2022]
Abstract
BACKGROUND Vasovagal syncope (VVS) is the result of an autonomic reflex that has a final effect of reducing sympathetic drive and increasing vagal activity. However, whether syncopal symptoms are associated with pathological cardiac autonomic modulation is not fully known. We tested the hypothesis that cardiac autonomic function is impaired in patients with VVS. METHODS Eighty-four consecutive patients (59 males; 48.8 ± 20.9 years) with recurrent unexplained syncope were enrolled. The head-up tilt test (HUTT) was positive in 38 patients and negative in 46 patients. Cardiac autonomic function was assessed by baroreflex sensitivity (BRS), heart rate variability, plasma concentrations of norepinephrine, and (123) I-metaiodobenzylguanidine (MIBG) scintigraphy. RESULTS BRS indices were significantly lower in the HUTT-positive group than in the HUTT-negative group (6.1 ± 5.5 mm Hg/s vs 9.8 ± 7.6 mm Hg/s, P = 0.02). With regard to cardiac (123) I-MIBG scintigraphy, the mean heart-to-mediastinum ratio at the delayed phase tended to be lower in HUTT-positive than in HUTT-negative individuals, but this difference was not significant (2.75 ± 0.55 vs 3.02 ± 0.49, P = 0.08).The percent washout rate of (123) I-MIBG was significantly higher in the positive group compared with the negative group (40.7 ± 13.1% vs 31.5 ± 13.3%, P = 0.02). Multivariate logistic analysis revealed that the appearance of HUTT-induced VVS was predicted independently by a high percent washout rate of (123) I-MIBG (odds ratio, 0.954; 95% confidence interval, 0.903-0.998; P = 0.048). CONCLUSIONS Our results suggest that pathological autonomic cardiac modulation may play a role in the appearance of syncope in VVS patients.
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Affiliation(s)
- Tetsuji Shinohara
- Department of Cardiology and Clinical Examination, Faculty of Medicine, Oita University, Oita, Japan
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292
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Drenjancevic I, Grizelj I, Harsanji-Drenjancevic I, Cavka A, Selthofer-Relatic K. The interplay between sympathetic overactivity, hypertension and heart rate variability (review, invited). ACTA ACUST UNITED AC 2014; 101:129-42. [PMID: 24901074 DOI: 10.1556/aphysiol.101.2014.2.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The control of arterial pressure is a complex interaction of the long- and short-term influences of hormones, local vascular factors, and neural mechanisms. The autonomic nervous system and its sympathetic arm play important roles in the regulation of blood pressure, and overactivity of sympathetic nerves may have an important role in the development of hypertension and related cardiovascular disorders. The baroreceptor system opposes either increases or decreases in arterial pressure, and the primary purpose of the arterial baroreflex is to keep blood pressure close to a particular set point over a relatively short period of time. The ability of the baroreflex to powerfully buffer acute changes in arterial pressure is well established, but the role of the arterial baroreceptor reflex in long-term control of arterial pressure has been a topic of many debate and controversy for decades. The sympathetic nervous system and arterial baroreceptor reflex control of renal sympathetic nerve activity has been proposed to play a role in long-term control of arterial pressure. The aim of this paper has been to review the postulated role of sympathetic activation.
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Affiliation(s)
- Ines Drenjancevic
- University of Osijek Department of Physiology and Immunology, Faculty of Medicine J. Huttlera 4 31000 Osijek Croatia University of Pécs Pécs Hungary
| | - I Grizelj
- University of Osijek Department of Physiology and Immunology, Faculty of Medicine J. Huttlera 4 31000 Osijek Croatia
| | - I Harsanji-Drenjancevic
- Clinical Hospital Center Osijek Department of Anesthesiology, Reanimatology and Intensive Care Unit Osijek Croatia
| | - A Cavka
- University of Osijek Department of Physiology and Immunology, Faculty of Medicine J. Huttlera 4 31000 Osijek Croatia
| | - K Selthofer-Relatic
- Clinical Hospital Center Osijek Department of Cardiology, Clinic of Internal Medicine Osijek Croatia University of Osijek Department of Internal Medicine, Medical Ethic and History of Medicine, Faculty of Medicine Osijek Croatia
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293
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Malamud-Kessler C, Bruno E, Chiquete E, Sentíes-Madrid H, Campos-Sánchez M. Pathophysiology of neurally-mediated syncope. Neurologia 2014; 31:620-627. [PMID: 24844455 DOI: 10.1016/j.nrl.2014.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 04/05/2014] [Indexed: 11/30/2022] Open
Abstract
INTRODUCTION Neurally-mediated syncope (NMS) is defined as a transient loss of consciousness due to an abrupt and intermittent drop in blood pressure (BP). OBJECTIVES This study describes the putative pathophysiological mechanisms giving rise to NMS, the role of baroreflex (BR), and the interaction of its main haemodynamic variables: heart rate (HR) and BP. DEVELOPMENT Episodic dysregulation affects control over the haemodynamic variables (HR and BP) mediated by baroreflex mechanisms. During active standing, individuals experience a profound transient drop in systolic BP due to the effect of gravity on the column of blood and probably also because of reflex vasodilation. Abnormalities in the BR in NMS could be due to a more profound drop in BP upon standing, or to delayed or incomplete vasoconstriction resulting from inhibited or delayed sympathetic activity. CONCLUSIONS Sympathetic hyperactivity is present in patients with NMS at rest and before syncope. During active standing or passive tilting, excessive tachycardia may be followed by bradycardia and profound hypotension. Recovery of systolic BP is delayed or incomplete.
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Affiliation(s)
- C Malamud-Kessler
- Departamento de Neurología y Psiquiatría, Laboratorio de Neurofisiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición «Salvador Zubirán», México, D.F.
| | - E Bruno
- Departamento de Neurología y Psiquiatría, Laboratorio de Neurofisiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición «Salvador Zubirán», México, D.F
| | - E Chiquete
- Departamento de Neurología y Psiquiatría, Instituto Nacional de Ciencias Médicas y Nutrición «Salvador Zubirán», México, D.F
| | - H Sentíes-Madrid
- Departamento de Neurología y Psiquiatría, Laboratorio de Neurofisiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición «Salvador Zubirán», México, D.F
| | - M Campos-Sánchez
- Departamento de Ciencias Exactas, Universidad Peruana Cayetano Heredia, Lima, Perú
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294
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La Rovere MT, Pinna GD. Beneficial effects of physical activity on baroreflex control in the elderly. Ann Noninvasive Electrocardiol 2014; 19:303-10. [PMID: 24844457 DOI: 10.1111/anec.12170] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The baroreflex mechanisms, by controlling autonomic outflow to the heart and circulation, contribute importantly to neural circulatory control. The main function of the baroreflex is to prevent wide fluctuations in arterial blood pressure and to maintain the physiological homeostasis under basal resting conditions and in response to acute stress. Baroreflex-mediated changes in autonomic outflow affect heart rate, myocardial contractility, and peripheral vascular resistance. The baroreflex control of heart rate is of particular interest in pathological conditions, since it has been associated with increased propensity for cardiac mortality and sudden death. Aging is associated with significant cardiovascular modifications. The changes in baroreflex function that occur with age have been systematically studied by several methodological approaches. The available evidence indicates a reduced arterial baroreflex control of heart rate favoring an increase in sympathetic and a decrease in parasympathetic drive to the heart as well as an impairment in the baroreceptor control of blood pressure. Both kinds of changes have resultant clinical implications. Exercise training can modulate the age-related decline in baroreflex function and the attending abnormalities in autonomic control, thus accounting for some of the beneficial effects of physical activity in reducing the risk of cardiovascular morbidity and mortality.
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Affiliation(s)
- Maria Teresa La Rovere
- Department of Cardiology and Biomedical Engineering, Fondazione "Salvatore Maugeri," IRCCS, Istituto Scientifico di Montescano (Pavia), Italy
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295
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Phillips AA, Krassioukov AV, Ainslie PN, Cote AT, Warburton DER. Increased central arterial stiffness explains baroreflex dysfunction in spinal cord injury. J Neurotrauma 2014; 31:1122-8. [PMID: 24634993 DOI: 10.1089/neu.2013.3280] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
After cervical spinal cord injury (SCI), orthostatic hypotension and intolerance commonly ensue. The cardiovagal baroreflex plays an important role in the acute regulation of blood pressure (BP) and is associated with the onset of presyncope. The cardiovagal baroreflex is dysfunctional after SCI; however, this may be influenced by either increased stiffening of the arteries containing the stretch-receptors (which has been shown in SCI) or a more downstream neural mechanism (i.e., solitary nucleus, sinoatrial node). Identifying where along this pathway baroreflex dysfunction occurs may highlight a potential therapeutic target. This study examined the relationship between spontaneous cardiovagal baroreflex sensitivity (BRS) and common carotid artery (CCA) stiffness in those with high level SCI before and after midodrine (alpha1-agonist) administration, as well as in able-bodied controls, to evaluate: (1) the role arterial stiffening plays mediating baroreflex function after SCI and (2) the effect of normalizing BP on these parameters. Three to five min recordings of beat-by-beat BP and heart rate, as well as 30 sec duration recordings of CCA diameter were used for analysis. All participants were tested supine and during upright-tilt. Arterial stiffness (β-stiffness index) was elevated in those with SCI when upright (+12%; p<0.05). Further, β-stiffness index was negatively related to reduced BRS in those with SCI when upright (R2=0.55; p<0.05), but not in able-bodied persons. Normalizing BP did not improve BRS or CCA stiffness. This study clearly shows that reduced BRS is closely related to increased arterial stiffness in the population with SCI.
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Affiliation(s)
- Aaron A Phillips
- 1 Cardiovascular Physiology and Rehabilitation Laboratory , Physical Activity Promotion and Chronic Disease Prevention Unit, University of British Columbia , Vancouver, Canada
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296
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Heart rate turbulence for predicting new-onset atrial fibrillation in patients undergoing coronary artery bypass grafting. Int J Cardiol 2014; 174:579-85. [PMID: 24798780 DOI: 10.1016/j.ijcard.2014.04.130] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 02/10/2014] [Accepted: 04/12/2014] [Indexed: 11/23/2022]
Abstract
BACKGROUND Cardiac autonomic dysfunction reportedly contributes to the AF triggering and maintenance. Heart rate turbulence (HRT) is a promising noninvasive measure of cardiac autonomic function. We investigated whether ambulatory ECG-based HRT measurement could predict in-hospital new-onset atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery. METHODS HRT onset (TO) and slope (TO) were prospectively measured from 24-h Holter recording in 113 consecutive patients prior to CABG. Abnormal HRT was defined as at least one abnormal value in TO (> 0%) and TS (< 2.5 ms/RR). RESULTS Patients with abnormal HRT (n = 60) showed a significantly higher AF incidence (47% versus 21%, P = 0.005) and AF burden (29 ± 9 versus 7 ± 5 h, P = 0.043) than those with normal HRT (n = 53). Abnormal HRT were identified as independent predictors for the new-onset postoperative AF. During the follow-up period (12.0 ± 10.5 months), the abnormal HRT group showed a worse prognosis versus the normal HRT group regarding the AF recurrence/postoperative stroke (P = 0.018). Additionally, the postoperative AF incidence, in-hospital AF burden, and the rate of AF recurrence/postoperative stroke gradually elevated as the number of abnormal HRT values increased from 0 to 2. CONCLUSIONS Preoperative abnormal HRT was significantly associated with worse short-term (in-hospital new-onset AF) and long-term outcomes (post-discharge AF recurrence/postoperative stroke) after CABG surgery. Additional studies incorporating preventive interventions depending on the preoperative HRT results might be worthwhile in this patient group.
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297
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Sbaraglia F, Mores N, Garra R, Giuratrabocchetta G, Lepore D, Molle F, Savino G, Piastra M, Pulitano' S, Sammartino M. Phenylephrine eye drops in pediatric patients undergoing ophthalmic surgery: incidence, presentation, and management of complications during general anesthesia. Paediatr Anaesth 2014; 24:400-5. [PMID: 24354865 DOI: 10.1111/pan.12329] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/16/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND Phenylephrine eye drops are widely used as mydriatic agent to reach the posterior segment of the eye. In literature, many reports suggest a systemic absorption of this agent as a source of severe adverse drug reactions. Hence, we reviewed our experience with topical phenylephrine in ophthalmic surgery. METHODS In May 2006, following US guidelines publication, a standard operating procedure was issued in our operating rooms to standardize the use of phenylephrine eye drops in our practice. Two years later, after the occurrence of a cluster of serious adverse drug reactions in infants undergoing surgery, a review of phenylephrine safety and systemic complications incidence was performed. RESULTS We observed 451 pediatric patients, and 187 met the inclusions criteria: Among them, 4 experienced hemodynamic complications due to phenylephrine eye drops. The incidence of major complications was 2.1%. CONCLUSIONS Two different patterns of side effects occurred. The first one was a cardiovascular derangement with severe hypertension and heart rate alterations; the other one involved exclusively pulmonary circuit causing early edema. These clinical manifestations, their duration, and treatment responses are all explainable by alfa1-adrenergic action of phenylephrine. This hypothetic pathogenesis has been confirmed also by the usefulness of direct vasodilators (anesthetic agents) and by the negative outcome occurred in the past with the use of beta-blockers.
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Affiliation(s)
- Fabio Sbaraglia
- Department of Anaesthesia and Intensive Care, Catholic University of Sacred Heart, Rome, Italy
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298
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Stockigt F, Pohlmann S, Nickenig G, Schwab JO, Schrickel JW. Induced and spontaneous heart rate turbulence in mice: influence of coupling interval. Europace 2014; 16:1092-8. [DOI: 10.1093/europace/eut357] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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299
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Pal GK, Adithan C, Ananthanarayanan PH, Pal P, Nanda N, Durgadevi T, Lalitha V, Syamsunder AN, Dutta TK. Effects of gender on sympathovagal imbalance, prehypertension status, and cardiovascular risks in first-degree relatives of type 2 diabetics. Am J Hypertens 2014; 27:317-24. [PMID: 24286720 DOI: 10.1093/ajh/hpt219] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Although cardiovascular (CV) risks are reported in first-degree relatives (FDRs) of type 2 diabetics, effects of gender on sympathovagal imbalance (SVI) and CV risks in these subjects have not been investigated. METHODS Body mass index (BMI), blood pressure variability parameters including baroreflex sensitivity (BRS), spectral indices of heart rate variability, autonomic function tests, insulin resistance, lipid profile, inflammatory markers (interleukin 6, high-sensitivity C-reactive protein, tumor necrosis factor α) and oxidative stress (OS) marker were measured and analyzed in control group (without family history of diabetes; 65 women, 60 men) and study group (FDRs of type 2 diabetics; 52 women, 49 men) subjects. RESULTS BMI, heart rate, blood pressure, rate-pressure product, stroke volume, left-ventricular ejection time, cardiac output, total peripheral resistance, homeostatic model of insulin resistance, lipid profile, inflammatory and OS markers, and ratio of low-frequency to high-frequency power of heart rate variability (LF-HF ratio), a sensitive marker of SVI, were significantly increased, and BRS was significantly decreased in study group men compared with women. SVI was more intense in men and was due to concomitant sympathetic activation and vagal inhibition. There was no SVI in control subjects. Multiple regression analysis demonstrated independent contribution of BMI, homeostatic model of insulin resistance, atherogenic index, inflammatory and OS markers, and BRS to LF-HF ratio. Logistic regression analysis demonstrated significant prediction of prehypertension status and rate-pressure product (markers of CV risk) by LF-HF, which was more prominent in men. CONCLUSIONS SVI is more intense in male FDRs of type 2 diabetics, and SVI is associated with increased CV risk due to insulin resistance, dyslipidemia, inflammation, and oxidative stress in these subjects.
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Affiliation(s)
- Gopal K Pal
- Department of Physiology, Jawaharlal Institute of Post-graduate Medical Education and Research, Puducherry, India
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300
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Pourshanazari AA, Mohagheghi O, Pilavarian AA, Enayatfard L, Shafei MN. Involvement of β-adrenergic receptor of nucleus tractus solitarius in changing of baroreflex sensitivity by estrogen in female rats. Adv Biomed Res 2014; 3:83. [PMID: 24761391 PMCID: PMC3988600 DOI: 10.4103/2277-9175.127996] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 07/10/2013] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Arterial baroreflex (ABR) is an important factor in preventing of blood pressure fluctuations that determined by baroreflex sensitivity (BRS). Estrogen is an ovarian hormone that has influence on ABR. The mechanism of this effect of estrogen unknown and may be mediated by β-adrenergic receptor of nucleus tractus solitarius (NTS), an important area in regulation of baroreflex. Therefore, in this study changing of BRS by estrogen after blockade β-adrenergic receptor of NTS in ovariectomized rats (Ovx) and Ovx treated with estrogen (Est) was examined. MATERIALS AND METHODS After ovariectomy, all female rats divided to Ovx and Ovx + Est groups and two series of experiments were performed. In the first experiment, phenylephrine was [intravenously, IV] injected in both the Ovx and Ovx + Est groups, and mean arterial pressure (MAP), heart rate (HR), and BRS were evaluated (n = 8 for each group). In the second experiment, each of Ovx and Ovx + Est groups divided into saline and propranolol (pro) groups, saline and pro stereotaxically were microinjected into NTS, respectively. Further, phenylephrine (IV) was injected in all groups and BRS was evaluated. RESULTS BRS significantly increased in estrogen-treated groups (Ovx + Est) compared to Ovx groups (P < 0.01). The blockade β-adrenergic receptor of NTS by pro did not significantly changed BRS in both Ovx and Ovx + Est groups. CONCLUSION We concluded that there aren't any intraction between estrogen and β-adrenergic receptor of NTS in BRS.
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Affiliation(s)
- Ali Asghar Pourshanazari
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | | | | | - Lili Enayatfard
- Neurocognitive Research Center and Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad N Shafei
- Neurocognitive Research Center and Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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