1
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Cui YX, Du JB, Jin HF. Baroreflex sensitivity and its implication in neurally mediated syncope in children. World J Pediatr 2023; 19:1023-1029. [PMID: 37014537 DOI: 10.1007/s12519-023-00693-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 01/20/2023] [Indexed: 04/05/2023]
Affiliation(s)
- Ya-Xi Cui
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Jun-Bao Du
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
- Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Beijing, 100191, China
| | - Hong-Fang Jin
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China.
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2
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Longo S, Legramante JM, Rizza S, Federici M. Vasovagal syncope: An overview of pathophysiological mechanisms. Eur J Intern Med 2023; 112:6-14. [PMID: 37030995 DOI: 10.1016/j.ejim.2023.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/09/2023] [Accepted: 03/23/2023] [Indexed: 04/10/2023]
Abstract
Syncope is a short-term transient loss of consciousness, characterized by rapid onset and complete spontaneous recovery. According to the 2018 European Society of Cardiology guidelines, three different types of syncope have been identified. However, all forms of syncope share a common final pathophysiological event, global cerebral hypoperfusion, which results from the inability of the circulatory system to maintain blood pressure at the level required to efficiently supply blood to the brain. The vasovagal syncope (VVS) is the most common form of syncope. Although, VVS is generally harmless, its frequent occurrence can negatively affect quality of life and increase the risk of adverse events. The pathophysiological mechanisms underlying VVS remain obscure. The multifaceted nature of VVS presents a veritable challenge to understanding this condition and developing preventative strategies. Thus, the aim of this review was to discuss the factors contributing to the pathogenesis of VVS and provide guidance for future research.
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Affiliation(s)
- Susanna Longo
- Department of Systems Medicine, University of Rome Tor Vergata, Via Montpellier 1, Rome 00133 ITALY
| | - Jacopo M Legramante
- Department of Systems Medicine, University of Rome Tor Vergata, Via Montpellier 1, Rome 00133 ITALY
| | - Stefano Rizza
- Department of Systems Medicine, University of Rome Tor Vergata, Via Montpellier 1, Rome 00133 ITALY
| | - Massimo Federici
- Department of Systems Medicine, University of Rome Tor Vergata, Via Montpellier 1, Rome 00133 ITALY.
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3
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Williams EL, Khan FM, Claydon VE. Counter pressure maneuvers for syncope prevention: A semi-systematic review and meta-analysis. Front Cardiovasc Med 2022; 9:1016420. [PMID: 36312294 PMCID: PMC9606335 DOI: 10.3389/fcvm.2022.1016420] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/20/2022] [Indexed: 11/24/2022] Open
Abstract
Physical counter pressure maneuvers (CPM) are movements that are recommended to delay or prevent syncope (fainting) by recruiting the skeletal muscle pump to augment cardiovascular control. However, these recommendations are largely based on theoretical benefit, with limited data evaluating the efficacy of CPM to prevent syncope in the real-world setting. We conducted a semi-systematic literature review and meta-analysis to assess CPM efficacy, identify literature gaps, and highlight future research needs. Articles were identified through a literature search (PubMed, April 2022) of peer-reviewed publications evaluating the use of counter pressure or other lower body maneuvers to prevent syncope. Two team members independently screened records for inclusion and extracted data. From 476 unique records identified by the search, 45 met inclusion criteria. Articles considered various syncopal conditions (vasovagal = 12, orthostatic hypotension = 8, postural orthostatic tachycardia syndrome = 1, familial dysautonomia = 2, spinal cord injury = 1, blood donation = 10, healthy controls = 11). Maneuvers assessed included hand gripping, leg fidgeting, stepping, tiptoeing, marching, calf raises, postural sway, tensing (upper, lower, whole body), leg crossing, squatting, “crash” position, and bending foreword. CPM were assessed in laboratory-based studies (N = 28), the community setting (N = 4), both laboratory and community settings (N = 3), and during blood donation (N = 10). CPM improved standing systolic blood pressure (+ 14.8 ± 0.6 mmHg, p < 0.001) and heart rate (+ 1.4 ± 0.5 bpm, p = 0.006), however, responses of total peripheral resistance, stroke volume, or cerebral blood flow were not widely documented. Most patients experienced symptom improvement following CPM use (laboratory: 60 ± 4%, community: 72 ± 9%). The most prominent barrier to employing CPM in daily living was the inability to recognize an impending faint. Patterns of postural sway may also recruit the skeletal muscle pump to enhance cardiovascular control, and its potential as a discrete, proactive CPM needs further evaluation. Physical CPM were successful in improving syncopal symptoms and producing cardiovascular responses that may bolster against syncope; however, practical limitations may restrict applicability for use in daily living.
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4
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Li L, Zhao H, Ma X, Jiao F, Lin J. Calcitonin gene-related peptide predicts therapeutic response to midodrine hydrochloride in children with vasovagal syncope. Front Neurosci 2022; 16:1026539. [PMID: 36267231 PMCID: PMC9577468 DOI: 10.3389/fnins.2022.1026539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/08/2022] [Indexed: 11/13/2022] Open
Abstract
The vasoconstriction agent midodrine hydrochloride is a vital treatment for pediatric patients diagnosed with vasovagal syncope (VVS), although the efficacy is variable. This study was designed to explore the value of calcitonin gene-related peptide (CGRP) in predicting the effect of midodrine hydrochloride treatment upon VVS patients. In total, 55 children diagnosed with VVS were treated with midodrine hydrochloride for 3 months. Therapeutic response was evaluated using a symptom score system. CGRP levels were significantly higher in VVS patients (68.700 ± 6.460) than in control subjects (43.400 ± 5.810; t = 18.207, P < 0.001) and symptom scores correlated positively with CGRP concentrations (r = 0.779, P < 0.001). Patients treated with midodrine hydrochloride showed a significant reduction in symptom scores [4 (0, 6.5) vs. 1 (1, 2); z = –6.481; P < 0.001]. However, the value of plasma CGRP were potently elevated in the positive-response subjects than in the negative-response subjects (70.080 ± 5.040) vs. (61.150 ± 3.090); t = 5.817; P < 0.001). The area under the ROC curve showed that the value of CGRP for predicting the therapeutic response to midodrine hydrochloride was 0.946 (95% CI: 0.879–0.997, P < 0.001). With high sensitivity (97.7%) and specificity (83.3%), CGRP predicted the therapeutic response to midodrine hydrochloride (cut-off value, 62.56 pg/ml). In conclusion, CGRP can be used to predict the effect of midodrine hydrochloride administration in VVS patients.
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Affiliation(s)
- Lintian Li
- School of Public Health, Xi’an Jiaotong University, Xi’an, China
| | - Huacai Zhao
- Department of Surgical, The Third Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, China
| | - Xiuxiu Ma
- School of Public Health, Xi’an Jiaotong University, Xi’an, China
| | - Fuyong Jiao
- Department of Pediatrics, The Third Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, China
| | - Jing Lin
- Key Laboratory for Disease Prevention and Control and Health Promotion of Shaanxi Province, Department of Child and Adolescent Health Science Center, Xi’an Jiaotong University, Xi’an, China
- *Correspondence: Jing Lin,
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5
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Pernice R, Sparacino L, Bari V, Gelpi F, Cairo B, Mijatovic G, Antonacci Y, Tonon D, Rossato G, Javorka M, Porta A, Faes L. Spectral decomposition of cerebrovascular and cardiovascular interactions in patients prone to postural syncope and healthy controls. Auton Neurosci 2022; 242:103021. [PMID: 35985253 DOI: 10.1016/j.autneu.2022.103021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 07/15/2022] [Accepted: 08/05/2022] [Indexed: 10/31/2022]
Abstract
We present a framework for the linear parametric analysis of pairwise interactions in bivariate time series in the time and frequency domains, which allows the evaluation of total, causal and instantaneous interactions and connects time- and frequency-domain measures. The framework is applied to physiological time series to investigate the cerebrovascular regulation from the variability of mean cerebral blood flow velocity (CBFV) and mean arterial pressure (MAP), and the cardiovascular regulation from the variability of heart period (HP) and systolic arterial pressure (SAP). We analyze time series acquired at rest and during the early and late phase of head-up tilt in subjects developing orthostatic syncope in response to prolonged postural stress, and in healthy controls. The spectral measures of total, causal and instantaneous coupling between HP and SAP, and between MAP and CBFV, are averaged in the low-frequency band of the spectrum to focus on specific rhythms, and over all frequencies to get time-domain measures. The analysis of cardiovascular interactions indicates that postural stress induces baroreflex involvement, and its prolongation induces baroreflex dysregulation in syncope subjects. The analysis of cerebrovascular interactions indicates that the postural stress enhances the total coupling between MAP and CBFV, and challenges cerebral autoregulation in syncope subjects, while the strong sympathetic activation elicited by prolonged postural stress in healthy controls may determine an increased coupling from CBFV to MAP during late tilt. These results document that the combination of time-domain and spectral measures allows us to obtain an integrated view of cardiovascular and cerebrovascular regulation in healthy and diseased subjects.
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Affiliation(s)
- Riccardo Pernice
- Department of Engineering, University of Palermo, Viale delle Scienze, Bldg. 9, 90128 Palermo, Italy
| | - Laura Sparacino
- Department of Engineering, University of Palermo, Viale delle Scienze, Bldg. 9, 90128 Palermo, Italy
| | - Vlasta Bari
- Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Francesca Gelpi
- Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy; Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Beatrice Cairo
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | | | - Yuri Antonacci
- Department of Physics and Chemistry "Emilio Segrè", University of Palermo, Viale delle Scienze, Bldg. 17, 90128 Palermo, Italy
| | - Davide Tonon
- Department of Neurology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Gianluca Rossato
- Department of Neurology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Michal Javorka
- Department of Physiology and the Biomedical Center Martin, Comenius University in Bratislava, Jessenius Faculty of Medicine, Martin, Slovakia
| | - Alberto Porta
- Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy; Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Luca Faes
- Department of Engineering, University of Palermo, Viale delle Scienze, Bldg. 9, 90128 Palermo, Italy.
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Comparison of pain-provoked versus standard 40-min tilt table test for the conformation of vasovagal syncope. Neurol Sci 2022; 43:4847-4851. [DOI: 10.1007/s10072-022-06079-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/15/2022] [Indexed: 10/18/2022]
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7
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Whittle RS, Keller N, Hall EA, Vellore HS, Stapleton LM, Findlay KH, Dunbar BJ, Diaz‐Artiles A. Gravitational Dose‐Response Curves for Acute Cardiovascular Hemodynamics and Autonomic Responses in a Tilt Paradigm. J Am Heart Assoc 2022; 11:e024175. [PMID: 35861832 PMCID: PMC9707822 DOI: 10.1161/jaha.121.024175] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background
The cardiovascular system is strongly dependent on the gravitational environment. Gravitational changes cause mechanical fluid shifts and, in turn, autonomic effectors influence systemic circulation and cardiac control. We implemented a tilt paradigm to (1) investigate the acute hemodynamic response across a range of directions of the gravitational vector, and (2) to generate specific dose‐response relationships of this gravitational dependency.
Methods and Results
Twelve male subjects were tilted from 45° head‐up tilt to 45° head‐down tilt in 15° increments, in both supine and prone postures. We measured the steady‐state hemodynamic response in a range of variables including heart rate, stroke volume, cardiac output, oxygen consumption, total peripheral resistance, blood pressure, and autonomic indices derived from heart rate variability analysis. There is a strong gravitational dependence in almost all variables considered, with the exception of oxygen consumption, whereas systolic blood pressure remained controlled to within ≈3% across the tilt range. Hemodynamic responses are primarily driven by differential loading on the baroreflex receptors, combined with differences in venous return to the heart. Thorax compression in the prone position leads to reduced venous return and increased sympathetic nervous activity, raising heart rate, and systemic vascular resistance while lowering cardiac output and stroke volume.
Conclusions
Gravitational dose‐response curves generated from these data provide a comprehensive baseline from which to assess the efficacy of potential spaceflight countermeasures. Results also assist clinical management of terrestrial surgery in prone posture or head‐down tilt positions.
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Affiliation(s)
- Richard S. Whittle
- Department of Aerospace Engineering Texas A&M University College Station TX
| | - Nathan Keller
- Department of Health and Kinesiology Texas A&M University College Station TX
| | - Eric A. Hall
- Department of Biomedical Engineering Texas A&M University College Station TX
| | | | | | | | - Bonnie J. Dunbar
- Department of Aerospace Engineering Texas A&M University College Station TX
| | - Ana Diaz‐Artiles
- Department of Aerospace Engineering Texas A&M University College Station TX
- Department of Health and Kinesiology Texas A&M University College Station TX
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8
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Goldstein DS. Stress and the "extended" autonomic system. Auton Neurosci 2021; 236:102889. [PMID: 34656967 PMCID: PMC10699409 DOI: 10.1016/j.autneu.2021.102889] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 09/06/2021] [Accepted: 09/28/2021] [Indexed: 12/22/2022]
Abstract
This review updates three key concepts of autonomic neuroscience-stress, the autonomic nervous system (ANS), and homeostasis. Hans Selye popularized stress as a scientific idea. He defined stress variously as a stereotyped response pattern, a state that evokes this pattern, or a stimulus that evokes the state. According to the "homeostat" theory stress is a condition where a comparator senses a discrepancy between sensed afferent input and a response algorithm, the integrated error signal eliciting specific patterns of altered effector outflows. Scientific advances since Langley's definition of the ANS have incited the proposal here of the "extended autonomic system," or EAS, for three reasons. (1) Several neuroendocrine systems are bound inextricably to Langley's ANS. The first to be described, by Cannon in the early 1900s, involves the hormone adrenaline, the main effector chemical of the sympathetic adrenergic system. Other neuroendocrine systems are the hypothalamic-pituitary-adrenocortical system, the arginine vasopressin system, and the renin-angiotensin-aldosterone system. (2) An evolving body of research links the ANS complexly with inflammatory/immune systems, including vagal anti-inflammatory and catecholamine-related inflammasomal components. (3) A hierarchical network of brain centers (the central autonomic network, CAN) regulates ANS outflows. Embedded within the CAN is the central stress system conceptualized by Chrousos and Gold. According to the allostasis concept, homeostatic input-output curves can be altered in an anticipatory, feed-forward manner; and prolonged or inappropriate allostatic adjustments increase wear-and-tear (allostatic load), resulting in chronic, stress-related, multi-system disorders. This review concludes with sections on clinical and therapeutic implications of the updated concepts offered here.
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Affiliation(s)
- David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; Autonomic Medicine Section, CNP/DIR/NINDS/NIH, 9000 Rockville Pike MSC-1620, Building 10 Room 8N260, Bethesda, MD 20892-1620, USA..
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Sheldon R, Faris P, Tang A, Ayala-Paredes F, Guzman J, Marquez M, Morillo CA, Krahn AD, Kus T, Ritchie D, Safdar S, Maxey C, Raj SR. Midodrine for the Prevention of Vasovagal Syncope : A Randomized Clinical Trial. Ann Intern Med 2021; 174:1349-1356. [PMID: 34339231 DOI: 10.7326/m20-5415] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Recurrent vasovagal syncope is common, responds poorly to treatment, and causes physical trauma and poor quality of life. Midodrine prevents hypotension and syncope during tilt tests in patients with vasovagal syncope. OBJECTIVE To determine whether midodrine can prevent vasovagal syncope in usual clinical conditions. DESIGN Randomized, double-blind, placebo-controlled clinical trial. (ClinicalTrials.gov: NCT01456481). SETTING 25 university hospitals in Canada, the United States, Mexico, and the United Kingdom. PATIENTS Patients with recurrent vasovagal syncope and no serious comorbid conditions. INTERVENTION Patients were randomly assigned 1:1 to placebo or midodrine and followed for 12 months. MEASUREMENTS The primary outcome measure was the proportion of patients with at least 1 syncope episode during follow-up. RESULTS The study included 133 patients who had had a median of 6 syncope episodes in the prior year (median age, 32 years; 73% female). Compared with patients receiving placebo, fewer patients receiving midodrine had at least 1 syncope episode (28 of 66 [42%] vs. 41 of 67 [61%]). The relative risk was 0.69 (95% CI, 0.49 to 0.97; P = 0.035). The absolute risk reduction was 19 percentage points (CI, 2 to 36 percentage points), and the number needed to treat to prevent 1 patient from having syncope was 5.3 (CI, 2.8 to 47.6). The time to first syncope was longer with midodrine (hazard ratio, 0.59 [CI, 0.37 to 0.96]; P = 0.035; log-rank P = 0.031). Adverse effects were similar in both groups. LIMITATION Small study size, young and healthy patients, relatively short observation period, and high proportion of patients from 1 center. CONCLUSION Midodrine can reduce the recurrence of syncope in healthy, younger patients with a high syncope burden. PRIMARY FUNDING SOURCE The Canadian Institutes of Health Research.
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Affiliation(s)
- Robert Sheldon
- University of Calgary, Calgary, Alberta, Canada (R.S., P.F., C.A.M., D.R., S.S., C.M.)
| | - Peter Faris
- University of Calgary, Calgary, Alberta, Canada (R.S., P.F., C.A.M., D.R., S.S., C.M.)
| | - Anthony Tang
- University of Western Ontario, London, Ontario, Canada (A.T.)
| | | | - Juan Guzman
- McMaster University, Hamilton, Ontario, Canada (J.G.)
| | - Manlio Marquez
- Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.M.)
| | - Carlos A Morillo
- University of Calgary, Calgary, Alberta, Canada (R.S., P.F., C.A.M., D.R., S.S., C.M.)
| | - Andrew D Krahn
- University of British Columbia, Vancouver, British Columbia, Canada (A.D.K.)
| | - Teresa Kus
- University of Montreal, Montreal, Quebec, Canada (T.K.)
| | - Debbie Ritchie
- University of Calgary, Calgary, Alberta, Canada (R.S., P.F., C.A.M., D.R., S.S., C.M.)
| | - Shahana Safdar
- University of Calgary, Calgary, Alberta, Canada (R.S., P.F., C.A.M., D.R., S.S., C.M.)
| | - Connor Maxey
- University of Calgary, Calgary, Alberta, Canada (R.S., P.F., C.A.M., D.R., S.S., C.M.)
| | - Satish R Raj
- University of Calgary, Calgary, Alberta, Canada, and Vanderbilt University School of Medicine, Nashville, Tennessee (S.R.R.)
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Khalilian MR, Ghasemi A, Khazaei N, Khoshkhou S, Mahmoudi E. Repolarization disparity as a predictor of response to Head up Tilt-table Test in pediatric syncope. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2021; 44:1397-1403. [PMID: 34181271 DOI: 10.1111/pace.14305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/01/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Head up Tilt-table Test (HUTT) is a practical examination of the most common type of pediatrics syncope. The electrocardiographic (ECG) changes during this test, show the autonomic defects that cause neuraly-mediated syncope in response to tilting process. METHODS All pediatric syncope patients referred to our center in a 1-year period, were included in the study. HUTT was performed and patients were classified into two groups of Negative and Positive HUTT results, and the latter group was subclassified as three subgroups of "vasodepressor", "cardioinhibitory" and "mixed type" responses to HUTT. QT and corrected QT (QTc) dispersion was measured by the baseline standard 12-lead ECG obtained before HUTT. RESULTS Eighty-six patients with a mean age of 12.19 ± 5.34 were included. Patients with positive HUTT were significantly younger and male gender was more prevalent in this group. Mean QT dispersion was significantly higher in patients with positive HUTT result and also in patients with mixed response to HUTT compared to isolated vasodepressor response. Duration of QTc interval did not change between different study groups. Reciever-Operating-Characteristic (ROC) analysis showed that QT dispersion higher than 32 ms is a significant predictor of positive HUTT result (with 92% sensitivity and 98% specificity) and values higher than 40 ms can predict the mixed type of response to HUTT (with 84% sensitivity and 63% specificity). CONCLUSIONS Baseline myocardial repolarization disparity significantly correlates with susceptibility to symptomatic vasovagal syncope. This pathology seems to play its role mainly via excessive vagotonic response to sympathetic activation during HUTT process (known as cardioinhibitory response).
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Affiliation(s)
- Mohammad Reza Khalilian
- Department of Pediatrics, School of Medicine, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abdolrahim Ghasemi
- Department of Pediatrics, School of Medicine, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Narges Khazaei
- Department of Pediatrics, School of Medicine, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sara Khoshkhou
- Department of Pediatrics, School of Medicine, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elham Mahmoudi
- Department of Pediatrics, School of Medicine, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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11
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Shenthar J, Gangwar RS, Banavalikar B, Benditt DG, Lakkireddy D, Padmanabhan D. A randomized study of yoga therapy for the prevention of recurrent reflex vasovagal syncope. Europace 2021; 23:1479-1486. [PMID: 34015829 DOI: 10.1093/europace/euab054] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 02/23/2021] [Indexed: 11/13/2022] Open
Abstract
AIMS Vasovagal syncope (VVS) is a common cardiovascular dysautonomic disorder that significantly impacts health and quality of life (QoL). Yoga has been shown to have a positive influence on cardiovascular autonomics. This study assessed the effectiveness of yoga therapy on the recurrence of VVS and QoL. METHODS AND RESULTS We randomized subjects with recurrent reflex VVS (>3 episodes in the past 1 year) and positive head-up tilt test to guideline-directed therapy (Group 1) or yoga therapy (Group 2). Patients in Group 1 were advised guideline-directed treatment and Group 2 was taught yoga by a certified instructor. The primary endpoint was VVS recurrences and QoL. Between June 2015 and February 2017, 97 highly symptomatic VVS patients were randomized (Group 1: 47 and Group 2: 50). The mean age was 33.1 ± 16.6 years, male:female of 40:57, symptom duration of 17.1 ± 20.7 months, with a mean of 6.4 ± 6.1 syncope episodes. Over a follow-up of 14.3 ± 2.1 months Group 2 had significantly lower syncope burden compared with Group 1 at 3 (0.8 ± 0.9 vs. 1.8 ± 1.4, P < 0.001), 6 (1.0 ± 1.2 vs. 3.4 ± 3.0, P < 0.001), and at 12 months (1.1 ± 0.8 vs. 3.8 ± 3.2, P < 0.001). The Syncope functional score questionnaire was significantly lower in Group 2 compared with Group 1 at 3 (31.4 ± 7.2 vs. 64.1 ± 11.5, P < 0.001), 6 (26.4 ± 6.3 vs. 61.4 ± 10.7, P < 0.001), and 12 months (22.2 ± 4.7 vs. 68.3 ± 11.4, P < 0.001). CONCLUSION For patients with recurrent VVS, guided yoga therapy is superior to conventional therapy in reducing symptom burden and improving QoL.
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Affiliation(s)
- Jayaprakash Shenthar
- Electrophysiology Unit, Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, 9th Block Jayanagar, Bannerghatta Road, Bangalore, Karnataka 560069, India
| | - Ritesh Singh Gangwar
- Electrophysiology Unit, Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, 9th Block Jayanagar, Bannerghatta Road, Bangalore, Karnataka 560069, India
| | - Bharatraj Banavalikar
- Electrophysiology Unit, Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, 9th Block Jayanagar, Bannerghatta Road, Bangalore, Karnataka 560069, India
| | - David G Benditt
- Cardiovascular Division, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Dhanunjaya Lakkireddy
- Cardiovascular Division, Kansas City Heart Rhythm Institute and Research Foundation, Overland Park, KS, USA
| | - Deepak Padmanabhan
- Electrophysiology Unit, Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, 9th Block Jayanagar, Bannerghatta Road, Bangalore, Karnataka 560069, India
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12
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Myrovali E, Fragakis N, Vassilikos V, Hadjileontiadis LJ. Efficient syncope prediction from resting state clinical data using wavelet bispectrum and multilayer perceptron neural network. Med Biol Eng Comput 2021; 59:1311-1324. [PMID: 33959855 DOI: 10.1007/s11517-021-02353-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 03/19/2021] [Indexed: 11/28/2022]
Abstract
Neurally mediated syncope (NMS) is the most common type of syncope, and head up tilt test (HUTT) is, so far, the most appropriate tool to identify NMS. In this work, an effort to predict the NMS before performing the HUTT is attempted. To achieve this, the heart rate variability (HRV) at rest and during the first minutes of tilting position during HUTT was analyzed using both time and frequency domains. Various features from HRV regularity and complexity, along with wavelet higher-order spectrum (WHOS) analysis in low-frequency (LF) and high-frequency (HF) bands were examined. The experimental results from 26 patients with history of NMS have shown that at rest, a time domain entropy measure and WHOS-based features in LF band exhibit significant differences between positive and negative HUTT as well as among 10 healthy subjects and NMS patients. The best performance of multilayer perceptron neural network (MPNN) was achieved by using an input vector consisted of WHOS-based HRV features in the LF zone and systolic blood pressure from the resting period, yielding an accuracy of 89.7%, assessed by 5-fold cross-validation. The promising results presented here pave the way for an early prediction of the HUTT outcome from resting state, contributing to the identification of patients at higher risk NMS. The HRV analysis along with systolic blood pressure at rest predict NMS using a multilayer perceptron neural network.
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Affiliation(s)
- Evangelia Myrovali
- Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, GR 54645, Thessaloniki, Greece.
| | - Nikolaos Fragakis
- 3rd Cardiology Department, Aristotle University of Thessaloniki, Hippokration General Hospital, 49 Konstantinoupoleos str, 54642, Thessaloniki, Greece
| | - Vassilios Vassilikos
- 3rd Cardiology Department, Aristotle University of Thessaloniki, Hippokration General Hospital, 49 Konstantinoupoleos str, 54642, Thessaloniki, Greece
| | - Leontios J Hadjileontiadis
- Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, GR 54645, Thessaloniki, Greece.,Department of Electrical and Computer Engineering, Khalifa University of Science and Technology, PO BOX 127788, Abu Dhabi, UAE
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Raphan T, Yakushin SB. Predicting Vasovagal Responses: A Model-Based and Machine Learning Approach. Front Neurol 2021; 12:631409. [PMID: 33776889 PMCID: PMC7988203 DOI: 10.3389/fneur.2021.631409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 02/12/2021] [Indexed: 11/23/2022] Open
Abstract
Vasovagal syncope (VVS) or neurogenically induced fainting has resulted in falls, fractures, and death. Methods to deal with VVS are to use implanted pacemakers or beta blockers. These are often ineffective because the underlying changes in the cardiovascular system that lead to the syncope are incompletely understood and diagnosis of frequent occurrences of VVS is still based on history and a tilt test, in which subjects are passively tilted from a supine position to 20° from the spatial vertical (to a 70° position) on the tilt table and maintained in that orientation for 10–15 min. Recently, is has been shown that vasovagal responses (VVRs), which are characterized by transient drops in blood pressure (BP), heart rate (HR), and increased amplitude of low frequency oscillations in BP can be induced by sinusoidal galvanic vestibular stimulation (sGVS) and were similar to the low frequency oscillations that presaged VVS in humans. This transient drop in BP and HR of 25 mmHg and 25 beats per minute (bpm), respectively, were considered to be a VVR. Similar thresholds have been used to identify VVR's in human studies as well. However, this arbitrary threshold of identifying a VVR does not give a clear understanding of the identifying features of a VVR nor what triggers a VVR. In this study, we utilized our model of VVR generation together with a machine learning approach to learn a separating hyperplane between normal and VVR patterns. This methodology is proposed as a technique for more broadly identifying the features that trigger a VVR. If a similar feature identification could be associated with VVRs in humans, it potentially could be utilized to identify onset of a VVS, i.e, fainting, in real time.
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Affiliation(s)
- Theodore Raphan
- Department of Computer and Information Science, Institute for Neural and Intelligent Systems, Brooklyn College of CUNY, Brooklyn, NY, United States.,Graduate Center of CUNY, New York, NY, United States
| | - Sergei B Yakushin
- Department of Neurology, Icahn School of Medicine at Mount Sinai Hospital, New York, NY, United States
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Aksu T, Guler TE, Bozyel S, Yalin K, Gopinathannair R. Usefulness of post-procedural heart rate response to predict syncope recurrence or positive head up tilt table testing after cardioneuroablation. Europace 2020; 22:1320-1327. [DOI: 10.1093/europace/euaa230] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
Abstract
Aims
Previous reports have suggested that cardioneuroablation (CNA) can be effective in reducing syncopal recurrences in patients with vasovagal syncope (VVS). This study assessed the efficacy of CNA in preventing a positive response to head-up tilt testing (HUT).
Methods and results
This is a single-centre retrospective study reviewing prospectively collected data. Fifty-one consecutive patients with VVS were included in the study. After confirmation of >3 s asystole on HUT, all patients underwent CNA. Head-up tilt testing was repeated 1 month after CNA. The main outcome measures were recurrence of syncope episode and positive response on HUT. During a median follow-up period of 11 months (interquartile range 3–27 months), all but 3 (5.8%) of 51 patients were free of syncope. Repeated HUTs were negative in 44 (86.2%) patients. When patients with recurrent syncope were excluded, vasodepressor response was seen in three cases and cardioinhibitory response in one case, respectively. Cardioneuroablation caused significant and durable shortening of RR interval in all cases. This effect was significantly higher in patients without positive HUT responses.
Conclusion
This pilot study shows that CNA can effectively prevent recurrent syncopal episodes in patients with refractory VVS. Head-up tilt testing seems as a valuable diagnostic tool not only to select suitable candidates and but also to evaluate success of CNA.
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Affiliation(s)
- Tolga Aksu
- Department of Cardiology, University of Health Sciences, Kocaeli Derince Training and Research Hospital, Kocaeli, Turkey
| | - Tumer Erdem Guler
- Department of Cardiology, University of Health Sciences, Kocaeli Derince Training and Research Hospital, Kocaeli, Turkey
| | - Serdar Bozyel
- Department of Cardiology, University of Health Sciences, Kocaeli Derince Training and Research Hospital, Kocaeli, Turkey
| | - Kivanc Yalin
- Department of Cardiology, Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
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Similar Cerebral Blood Flow and Autonomic Responses to Upright Tilt Test in Adult Patients With Different Hemodynamic Mechanisms Leading to Reflex Syncope. J Clin Neurophysiol 2020; 37:239-245. [DOI: 10.1097/wnp.0000000000000628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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16
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Tao C, Li X, Tang C, Jin H, Du J. Baroreflex Sensitivity Predicts Response to Metoprolol in Children With Vasovagal Syncope: A Pilot Study. Front Neurosci 2019; 13:1329. [PMID: 31920498 PMCID: PMC6923178 DOI: 10.3389/fnins.2019.01329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/26/2019] [Indexed: 12/25/2022] Open
Abstract
Objective: To explore the role of baroreflex sensitivity (BRS) in the head-up tilt test (HUTT) in predicting the therapeutic response of vasovagal syncope (VVS) patients to metoprolol. Materials and Methods: Vasovagal syncope patients treated with metoprolol were enrolled in this study and were classified as responders or non-responders according to changes in their symptom scores before and after metoprolol treatment. Values of BRS in the supine position and at positive response occurrence in the HUTT were obtained, and BRS changes from supine to positive response occurrence were calculated. Differences between responders and non-responders were analyzed. Receiver operating characteristic curve analysis was performed to assess the value of BRS for predicting the therapeutic efficacy of metoprolol in pediatric patients with VVS. Results: Forty patients (14 boys; 11.8 ± 2.5 years) diagnosed with VVS were recruited in the study, 28 of whom were verified to be responders to metoprolol and 12 of whom were verified as non-responders. They did not show any differences in baseline characteristics and hemodynamics in the HUTT (p > 0.05). However, the responders had an obviously increased supine BRS value compared to the non-responders (16.9 ± 7.7 ms/mmHg vs. 7.6 ± 3.8 ms/mmHg; p < 0.01). No difference in BRS at positive response occurrence was observed between the two groups (8.9 ± 8.5 ms/mmHg vs. 10.6 ± 9.8 ms/mmHg; p > 0.05). Accordingly, the changes in the BRS of responders were more obvious than in non-responders (8.0 ± 7.8 ms/mmHg vs. -3.0 ± 10.4 ms/mmHg; p < 0.01). The area under the receiver operating characteristic curve for the predictive value of supine BRS was 0.887 (95% CI, 0.779-0.995; p < 0.01). A cut-off value of 10 ms/mmHg yielded a sensitivity and specificity of 82 and 83%, respectively, in predicting the therapeutic efficacy of metoprolol in pediatric VVS patients. The area under the receiver operating characteristic curve for the predictive value of BRS changes was 0.827 (95% CI, 0.693-0.962; p < 0.01). A cut-off value of 4 ms/mmHg yielded a sensitivity and specificity of 71 and 83%, respectively. Conclusion: Baroreflex sensitivity may predict the response of children with VVS to metoprolol.
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Affiliation(s)
- Chunyan Tao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Research Unit of Clinical Diagnosis and Treatment of Pediatric Syncope and Cardiovascular Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Xueying Li
- Department of Medical Statistics, Peking University First Hospital, Beijing, China
| | - Chaoshu Tang
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
- Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Beijing, China
| | - Hongfang Jin
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Research Unit of Clinical Diagnosis and Treatment of Pediatric Syncope and Cardiovascular Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Junbao Du
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Research Unit of Clinical Diagnosis and Treatment of Pediatric Syncope and Cardiovascular Diseases, Chinese Academy of Medical Sciences, Beijing, China
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Cardiac and Vascular Sympathetic Baroreflex Control during Orthostatic Pre-Syncope. J Clin Med 2019; 8:jcm8091434. [PMID: 31510103 PMCID: PMC6781174 DOI: 10.3390/jcm8091434] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 11/17/2022] Open
Abstract
We hypothesized that sympathetic baroreflex mediated uncoupling between neural sympathetic discharge pattern and arterial pressure (AP) fluctuations at 0.1 Hz during baroreceptor unloading might promote orthostatic pre-syncope. Ten volunteers (32 ± 6 years) underwent electrocardiogram, beat-to-beat AP, respiratory activity and muscle sympathetic nerve activity (MSNA) recordings while supine (REST) and during 80° head-up tilt (HUT) followed by -10 mmHg stepwise increase of lower body negative pressure until pre-syncope. Cardiac and sympathetic baroreflex sensitivity were quantified. Spectrum analysis of systolic and diastolic AP (SAP and DAP) and calibrated MSNA (cMSNA) variability assessed the low frequency fluctuations (LF, ~0.1 Hz) of SAP, DAP and cMSNA variability. The squared coherence function (K2) quantified the coupling between cMSNA and DAP in the LF band. Analyses were performed while supine, during asymptomatic HUT (T1) and at pre-syncope onset (T2). During T2 we found that: (1) sympathetic baroreceptor modulation was virtually abolished compared to T1; (2) a progressive decrease in AP was accompanied by a persistent but chaotic sympathetic firing; (3) coupling between cMSNA and AP series at 0.1 Hz was reduced compared to T1. A negligible sympathetic baroreceptor modulation during pre-syncope might disrupt sympathetic discharge pattern impairing the capability of vessels to constrict and promote pre-syncope.
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18
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Barbic F, Heusser K, Minonzio M, Shiffer D, Cairo B, Tank J, Jordan J, Diedrich A, Gauger P, Zamuner RA, Porta A, Furlan R. Effects of Prolonged Head-Down Bed Rest on Cardiac and Vascular Baroreceptor Modulation and Orthostatic Tolerance in Healthy Individuals. Front Physiol 2019; 10:1061. [PMID: 31507438 PMCID: PMC6716544 DOI: 10.3389/fphys.2019.01061] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 08/02/2019] [Indexed: 11/13/2022] Open
Abstract
Orthostatic intolerance commonly occurs after prolonged bed rest, thus increasing the risk of syncope and falls. Baroreflex-mediated adjustments of heart rate and sympathetic vasomotor activity (muscle sympathetic nerve activity – MSNA) are crucial for orthostatic tolerance. We hypothesized that prolonged bed rest deconditioning alters overall baroreceptor functioning, thereby reducing orthostatic tolerance in healthy volunteers. As part of the European Space Agency Medium-term Bed Rest protocol, 10 volunteers were studied before and after 21 days of −6° head down bed rest (HDBR). In both conditions, subjects underwent ECG, beat-by-beat blood pressure, respiratory activity, and MSNA recordings while supine (REST) and during a 15-min 80° head-up tilt (TILT) followed by a 3-min −10 mmHg stepwise increase of lower body negative pressure to pre-syncope. Cardiac baroreflex sensitivity (cBRS) was obtained in the time (sequence method) and frequency domain (spectrum and cross-spectrum analyses of RR interval and systolic arterial pressure – SAP, variability). Baroreceptor modulation of sympathetic discharge activity to the vessels (sBRS) was estimated by the slope of the regression line between the percentage of MSNA burst occurrence and diastolic arterial pressure. Orthostatic tolerance significantly decreased after HDBR (12 ± 0.6 min) compared to before (21 ± 0.6 min). While supine, heart rate, SAP, and cBRS were unchanged before and after HDBR, sBRS gain was slightly depressed after than before HDBR (sBRS: −6.0 ± 1.1 versus −2.9 ± 1.5 burst% × mmHg−1, respectively). During TILT, HR was higher after than before HDBR (116 ± 4 b/min versus 100 ± 4 b/min, respectively), SAP was unmodified in both conditions, and cBRS indexes were lower after HDBR (α index: 3.4 ± 0.7 ms/mmHg; BRSSEQ 4.0 ± 1.0) than before (α index: 6.4 ± 1.0 ms/mmHg; BRSSEQ 6.8 ± 1.2). sBRS gain was significantly more depressed after HDBR than before (sBRS: −2.3 ± 0.7 versus −4.4 ± 0.4 burst% × mmHg−1, respectively). Our findings suggest that baroreflex-mediated adjustments in heart rate and MSNA are impaired after prolonged bed rest. The mechanism likely contributes to the decrease in orthostatic tolerance.
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Affiliation(s)
- Franca Barbic
- Humanitas Clinical and Research Center, Department of Internal Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Humanitas University, Rozzano, Italy
| | - Karsten Heusser
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
| | - Maura Minonzio
- Humanitas Clinical and Research Center, Department of Internal Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Humanitas University, Rozzano, Italy
| | - Dana Shiffer
- Humanitas Clinical and Research Center, Department of Internal Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Humanitas University, Rozzano, Italy
| | - Beatrice Cairo
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Jens Tank
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
| | - Jens Jordan
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
| | - André Diedrich
- Autonomic Dysfunction Center, Clinical Research Center (CRC), Department of Medicine, Vanderbilt University, Nashville, TN, United States
| | - Peter Gauger
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
| | | | - Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.,Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico di San Donato, San Donato Milanese, Italy
| | - Raffaello Furlan
- Humanitas Clinical and Research Center, Department of Internal Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Humanitas University, Rozzano, Italy
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Suspension syndrome: a potentially fatal vagally mediated circulatory collapse-an experimental randomized crossover trial. Eur J Appl Physiol 2019; 119:1353-1365. [PMID: 30895459 PMCID: PMC6517360 DOI: 10.1007/s00421-019-04126-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 03/13/2019] [Indexed: 12/22/2022]
Abstract
Purpose Suspension syndrome describes a potentially life-threatening event during passive suspension on a rope. The pathophysiological mechanism is not fully understood and optimal treatment unknown. We aimed to elucidate the pathophysiology and to give treatment recommendations. Methods In this experimental, randomized crossover trial, 20 healthy volunteers were suspended in a sit harness for a maximum of 60 min, with and without prior climbing. Venous pooling was assessed by measuring the diameter of the superficial femoral vein (SFV), lower leg tissue oxygenation (StO2) and by determining localized bioelectrical impedance. Hemodynamic response was assessed by measuring heart rate, blood pressure, stroke volume, and left ventricular diameters. Signs and symptoms of pre-syncope were recorded. Results Twelve (30%) out of 40 tests were prematurely terminated due to pre-syncopal symptoms (mean 44.7 min, minimum 13.4, maximum 59.7). SFV diameter increased, StO2 and the capacitive resistance of the cells decreased indicating venous pooling. Heart rate and blood pressure did not change in participants without pre-syncope. In contrast, in participants experiencing pre-syncope, heart rate and blood pressure dropped immediately before the event. All symptoms dissolved and values returned to normal within 5 min with participants in a supine position. Conclusions Sudden pre-syncope during passive suspension in a harness was observed in 30% of the tests. Blood pools in the veins of the lower legs; however, a vagal mechanism finally leads to loss of consciousness. Time to pre-syncope is unpredictable and persons suspended on a rope should be rescued and put into a supine position as soon as possible. Electronic supplementary material The online version of this article (10.1007/s00421-019-04126-5) contains supplementary material, which is available to authorized users.
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20
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Carter JR. Microneurography and sympathetic nerve activity: a decade-by-decade journey across 50 years. J Neurophysiol 2019; 121:1183-1194. [PMID: 30673363 DOI: 10.1152/jn.00570.2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The technique of microneurography has advanced the field of neuroscience for the past 50 years. While there have been a number of reviews on microneurography, this paper takes an objective approach to exploring the impact of microneurography studies. Briefly, Web of Science (Thomson Reuters) was used to identify the highest citation articles over the past 50 years, and key findings are presented in a decade-by-decade highlight. This includes the establishment of microneurography in the 1960s, the acceleration of the technique by Gunnar Wallin in the 1970s, the international collaborations of the 1980s and 1990s, and finally the highest impact studies from 2000 to present. This journey through 50 years of microneurographic research related to peripheral sympathetic nerve activity includes a historical context for several of the laboratory interventions commonly used today (e.g., cold pressor test, mental stress, lower body negative pressure, isometric handgrip, etc.) and how these interventions and experimental approaches have advanced our knowledge of cardiovascular, cardiometabolic, and other human diseases and conditions.
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Affiliation(s)
- Jason R Carter
- Department of Kinesiology and Integrative Physiology, Michigan Technological University , Houghton, Michigan
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21
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He W, Wang X, Liu S, Yu X, Lu Z, Ma R, Luo D, Xie J, He B, Jiang H. Sympathetic mechanisms in an animal model of vasovagal syncope. Clin Auton Res 2018; 28:333-340. [DOI: 10.1007/s10286-018-0503-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/11/2018] [Indexed: 11/24/2022]
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Jardine DL, Wieling W, Brignole M, Lenders JWM, Sutton R, Stewart J. The pathophysiology of the vasovagal response. Heart Rhythm 2017; 15:921-929. [PMID: 29246828 DOI: 10.1016/j.hrthm.2017.12.013] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Indexed: 10/18/2022]
Abstract
In part I of this study, we found that the classical studies on vasovagal syncope, conducted in fit young subjects, overstated vasodilatation as the dominant hypotensive mechanism. Since 1980, blood pressure and cardiac output have been measured continuously using noninvasive methods during tilt, mainly in patients with recurrent syncope, including women and the elderly. This has allowed us to analyze in more detail the complex sequence of hemodynamic changes leading up to syncope in the laboratory. All tilt-sensitive patients appear to progress through 4 phases: (1) early stabilization, (2) circulatory instability, (3) terminal hypotension, and (4) recovery. The physiology responsible for each phase is discussed. Although the order of phases is consistent, the time spent in each phase may vary. In teenagers and young adults, progressive hypotension during phases 2 and 3 can be driven by vasodilatation or falling cardiac output. The fall in cardiac output is secondary to a progressive decrease in stroke volume because blood is pooled in the splanchnic veins. In adults a fall in cardiac output is the dominant hypotensive mechanism because systemic vascular resistance always remains above baseline levels.
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Affiliation(s)
- David L Jardine
- Department of General Medicine, Christchurch Hospital, University of Otago, Christchurch, New Zealand.
| | - Wouter Wieling
- Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Michele Brignole
- Department of Cardiology, Arrhythmologic Centre, Ospedali del Tigullio, Lavagna, Italy
| | - Jacques W M Lenders
- Department of Internal Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Internal Medicine III, Technical University Dresden, Dresden, Germany
| | - Richard Sutton
- National Heart and Lung institute, Imperial College, London, United Kingdom
| | - Julian Stewart
- Departments of Pediatrics, Physiology, and Medicine, New York Medical College, Valhalla, New York
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Lee SH, Yang JH, Yim HR, Park J, Park SJ, Park KM, On YK, Kim JS. Hemodynamic parameters and baroreflex sensitivity during head-up tilt test in patients with neurally mediated syncope. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2017; 40:1454-1461. [PMID: 29023796 DOI: 10.1111/pace.13217] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 08/01/2017] [Accepted: 10/01/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND We aimed to investigate differences in hemodynamic parameters and the role of baroreflex sensitivity (BRS) in patients with a history of neurally mediated syncope (NMS) compared with a control group. METHODS Hemodynamic parameters and BRS were continuously measured noninvasively using a Finometer at rest and during passive head-up tilt test (HUT) in patients with a history of NMS (n = 55) and a control group (n = 77). The tilting period was divided into pretest (resting supine position), initial (first 3 minutes of tilting), last (last 3 minutes of tilting), and recovery (3 minutes after tilting was complete) periods. RESULTS Decrease in systolic blood pressure (- 14.7 ± 15.7 mm Hg vs - 7.6 ± 14.3 mm Hg, P < 0.01) was more prominent and increase in total systemic peripheral resistance was significantly smaller (67.6 ± 418.7 dyn.s/cm5 vs 189.4 ± 261.0 dyn.s/cm5 , P = 0.04) from the initial to the last period of HUT in the patient group compared with the control group. BRS was significantly higher during the pretest period (20.1 ± 10.9 ms/mm Hg vs 13.0 ± 8.1 ms/mm Hg, P < 0.01) in the patient group, while the decrease in BRS from the pretest to the initial period was greater (-8.5 ± 6.0 ms/mm Hg vs - 3.2 ± 4.1 ms/mm Hg, P = 0.01). CONCLUSIONS Dysfunctional BRS in response to orthostatic stress might be involved in pathological autonomic cardiac modulation of NMS.
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Affiliation(s)
- Sung Ho Lee
- Division of Cardiology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Ji Hyun Yang
- Korea Association of Health Promotion, Seoul, Republic of Korea
| | - Hye Ran Yim
- Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jungwae Park
- Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Seung-Jung Park
- Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Kyoung-Min Park
- Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Young Keun On
- Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - June Soo Kim
- Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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A risk prediction score model for predicting occurrence of post-PCI vasovagal reflex syndrome: a single center study in Chinese population. JOURNAL OF GERIATRIC CARDIOLOGY : JGC 2017; 14:509-514. [PMID: 29089967 PMCID: PMC5653897 DOI: 10.11909/j.issn.1671-5411.2017.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Background The vasovagal reflex syndrome (VVRS) is common in the patients undergoing percutaneous coronary intervention (PCI). However, prediction and prevention of the risk for the VVRS have not been completely fulfilled. This study was conducted to develop a Risk Prediction Score Model to identify the determinants of VVRS in a large Chinese population cohort receiving PCI. Methods From the hospital electronic medical database, we identified 3550 patients who received PCI (78.0% males, mean age 60 years) in Chinese PLA General Hospital from January 1, 2000 to August 30, 2016. The multivariate analysis and receiver operating characteristic (ROC) analysis were performed. Results The adverse events of VVRS in the patients were significantly increased after PCI procedure than before the operation (all P< 0.001). The rate of VVRS [95% confidence interval (CI)] in patients receiving PCI was 4.5% (4.1%–5.6%). Compared to the patients suffering no VVRS, incidence of VVRS involved the following factors, namely female gender, primary PCI, hypertension, over two stents implantation in the left anterior descending (LAD), and the femoral puncture site. The multivariate analysis suggested that they were independent risk factors for predicting the incidence of VVRS (all P < 0.001). We developed a risk prediction score model for VVRS. ROC analysis showed that the risk prediction score model was effectively predictive of the incidence of VVRS in patients receiving PCI (c-statistic 0.76, 95% CI: 0.72–0.79, P < 0.001). There were decreased events of VVRS in the patients receiving PCI whose diastolic blood pressure dropped by more than 30 mmHg and heart rate reduced by 10 times per minute (AUC: 0.84, 95% CI: 0.81–0.87, P < 0.001). Conclusion The risk prediction score is quite efficient in predicting the incidence of VVRS in patients receiving PCI. In which, the following factors may be involved, the femoral puncture site, female gender, hypertension, primary PCI, and over 2 stents implanted in LAD.
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Khurana RK. Initial orthostatic and non-orthostatic hypotension in wrestler’s syncope. Clin Auton Res 2017; 27:423-426. [DOI: 10.1007/s10286-017-0476-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 10/03/2017] [Indexed: 10/18/2022]
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Singhania PK, Ranwa BL, Gupta S. Correlation of head-up tilt table test time interval with future risk of recurrent syncope. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2017; 40:1462-1465. [PMID: 29023991 DOI: 10.1111/pace.13219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 09/11/2017] [Accepted: 09/22/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Head-up tilt table test (HUTT) is widely used for the investigation of syncope and presyncope. Time required for positive response has a probable relationship to the sensitivity of neural reflex mechanism underlying syncope. METHODS We evaluated patients with history of syncope. Group A included patients with recurrent syncope defined as two or more episodes of syncope and group B included those with one episode of syncope. Time required for the test to become positive in both the groups was analyzed. Patients with positive HUTT were followed for 1 year. RESULTS Of 80 patients, 68 eligible study patients were divided into group A (32.35%) and group B (67.65%). HUTT was positive in 41 patients (positivity rate = 60.29%). Positivity rate was 100% in group A and 41.3% in group B. Median time interval for positive response in groups A and B were 12.5 and 30.0 minutes, respectively. An inverse association was found between recurrent syncope and time interval for positive response (R = - 0.282, P = 0.002). Time interval of less than 19.5 minutes for positive response had 94.5% sensitivity and 97.89% specificity for recurrent syncope. On follow-up, positive association was found between time interval for positive response less than 19.5 minutes and future recurrence of syncope (odds ratio = 22.75, 95% confidence interval = 4.37-118.34, P = 0.000). CONCLUSION HUTT time interval of less than 19.5 minutes for positive response predicted future recurrence of syncope. Hence, it may serve as an important predictor of future recurrence of syncope.
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Affiliation(s)
- Priti K Singhania
- Postgraduate Department of Cardiology, J.L.N. Medical College, Ajmer, Rajasthan, India
| | - Bhanwar L Ranwa
- Postgraduate Department of Cardiology, J.L.N. Medical College, Ajmer, Rajasthan, India
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Lund A, Sørensen H, Jensen TW, Niemann MJ, Olesen ND, Nielsen HB, Olsen NV, Secher NH. Muscle oxygen saturation increases during head-up tilt-induced (pre)syncope. Acta Physiol (Oxf) 2017; 221:74-80. [PMID: 28262007 DOI: 10.1111/apha.12863] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 02/18/2017] [Accepted: 02/23/2017] [Indexed: 11/28/2022]
Abstract
AIM To evaluate whether muscle vasodilatation plays a role for hypotension developed during central hypovolaemia, muscle oxygenation (Sm O2 ) was examined during (pre)syncope induced by head-up tilt (HUT). Skin blood flow (SkBF) and oxygenation (Sskin O2 ) were determined because evaluation of Sm O2 may be affected by superficial tissue oxygenation. Furthermore, we evaluated cerebral oxygenation (Sc O2 ) and middle cerebral artery mean blood flow velocity (MCAvmean ). METHODS Twenty healthy male volunteers (median age 24 years; range 19-38) were subjected to passive 50° HUT for 1 h or until (pre)syncope. Sc O2 and Sm O2 (near-infrared spectroscopy), MCAvmean (transcranial Doppler) along with mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) (Modelflow® ) were determined. RESULTS (Pre)syncopal symptoms appeared in 17 subjects after 11 min (median; range 2-34) accompanied by a decrease in MAP, SV, CO and TPR, while HR remained elevated. During (pre)syncope, Sc O2 decreased [73% (71-76; mean and 95% CI) to 68% (65-71), P < 0.0001] along with MCAvmean [40 (37-43) to 32 (29-35) cm s-1 , P < 0.0001]. In contrast, Sm O2 increased [63 (56-69)% to 71% (65-78), P < 0.0001], while Sskin O2 [64% (58-69) to 53% (47-58), P < 0.0001] and SkBF [71 (44-98) compared to a baseline of 99 (72-125) units, P = 0.020] were reduced. CONCLUSION We confirm that the decrease in MAP during HUT is associated with a reduction in indices of cerebral perfusion. (Pre)syncope was associated with an increase in Sm O2 despite reduced Sskin O2 and SkBF, supporting that muscle vasodilation plays an important role in the circulatory events leading to hypotension during HUT.
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Affiliation(s)
- A. Lund
- Department of Neuroanaesthesia; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
| | - H. Sørensen
- The Copenhagen Muscle Research Centre; Department of Anaesthesia; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
| | - T. W. Jensen
- The Copenhagen Muscle Research Centre; Department of Anaesthesia; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
| | - M. J. Niemann
- The Copenhagen Muscle Research Centre; Department of Anaesthesia; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
| | - N. D. Olesen
- The Copenhagen Muscle Research Centre; Department of Anaesthesia; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
| | - H. B. Nielsen
- The Copenhagen Muscle Research Centre; Department of Anaesthesia; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
| | - N. V. Olsen
- Department of Neuroanaesthesia; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
| | - N. H. Secher
- The Copenhagen Muscle Research Centre; Department of Anaesthesia; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
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Cohen B, Martinelli GP, Xiang Y, Raphan T, Yakushin SB. Vestibular Activation Habituates the Vasovagal Response in the Rat. Front Neurol 2017; 8:83. [PMID: 28360882 PMCID: PMC5350135 DOI: 10.3389/fneur.2017.00083] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/24/2017] [Indexed: 12/16/2022] Open
Abstract
Vasovagal syncope is a significant medical problem without effective therapy, postulated to be related to a collapse of baroreflex function. While some studies have shown that repeated static tilts can block vasovagal syncope, this was not found in other studies. Using anesthetized, male Long–Evans rats that were highly susceptible to generation of vasovagal responses, we found that repeated activation of the vestibulosympathetic reflex (VSR) with ±2 and ±3 mA, 0.025 Hz sinusoidal galvanic vestibular stimulation (sGVS) caused incremental changes in blood pressure (BP) and heart rate (HR) that blocked further generation of vasovagal responses. Initially, BP and HR fell ≈20–50 mmHg and ≈20–50 beats/min (bpm) into a vasovagal response when stimulated with Sgv\S in susceptible rats. As the rats were continually stimulated, HR initially rose to counteract the fall in BP; then the increase in HR became more substantial and long lasting, effectively opposing the fall in BP. Finally, the vestibular stimuli simply caused an increase in BP, the normal sequence following activation of the VSR. Concurrently, habituation caused disappearance of the low-frequency (0.025 and 0.05 Hz) oscillations in BP and HR that must be present when vasovagal responses are induced. Habituation also produced significant increases in baroreflex sensitivity (p < 0.001). Thus, repeated low-frequency activation of the VSR resulted in a reduction and loss of susceptibility to development of vasovagal responses in rats that were previously highly susceptible. We posit that reactivation of the baroreflex, which is depressed by anesthesia and the disappearance of low-frequency oscillations in BP and HR are likely to be critically involved in producing resistance to the development of vasovagal responses. SGVS has been widely used to activate muscle sympathetic nerve activity in humans and is safe and well tolerated. Potentially, it could be used to produce similar habituation of vasovagal syncope in humans.
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Affiliation(s)
- Bernard Cohen
- Department of Neurology, Icahn School of Medicine at Mount Sinai , New York, NY , USA
| | - Giorgio P Martinelli
- Department of Neurology, Icahn School of Medicine at Mount Sinai , New York, NY , USA
| | - Yongqing Xiang
- Department of Computer and Information Science, Brooklyn College, City University of New York , New York, NY , USA
| | - Theodore Raphan
- Department of Computer and Information Science, Brooklyn College, City University of New York , New York, NY , USA
| | - Sergei B Yakushin
- Department of Neurology, Icahn School of Medicine at Mount Sinai , New York, NY , USA
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Fu Q, Levine BD. Syncope prevention in blood donors: when to do what? Transfusion 2016; 56:2399-2402. [DOI: 10.1111/trf.13775] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 07/18/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Qi Fu
- Institute for Exercise and Environmental Medicine; Texas Health Presbyterian Hospital Dallas; Dallas TX
| | - Benjamin D. Levine
- Institute for Exercise and Environmental Medicine; Texas Health Presbyterian Hospital Dallas; Dallas TX
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McBride DW, Reis C, Frank E, Klebe DW, Zhang JH, Applegate R, Tang J. An Experimental Model of Vasovagal Syncope Induces Cerebral Hypoperfusion and Fainting-Like Behavior in Awake Rats. PLoS One 2016; 11:e0163280. [PMID: 27658057 PMCID: PMC5033448 DOI: 10.1371/journal.pone.0163280] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/05/2016] [Indexed: 11/25/2022] Open
Abstract
Vasovagal syncope, a contributing factor to elderly falls, is the transient loss of consciousness caused by decreased cerebral perfusion. Vasovagal syncope is characterized by hypotension, bradycardia, and reduced cerebral blood flow, resulting in fatigue, altered coordination, and fainting. The purpose of this study is to develop an animal model which is similar to human vasovagal syncope and establish an awake animal model of vasovagal syncope. Male Sprague-Dawley rats were subjected to sinusoidal galvanic vestibular stimulation (sGVS). Blood pressure, heart rate, and cerebral blood flow were monitored before, during, and post-stimulation. sGVS resulted in hypotension, bradycardia, and decreased cerebral blood flow. One cohort of animals was subjected to sGVS while freely moving. sGVS in awake animals produced vasovagal syncope-like symptoms, including fatigue and uncoordinated movements; two animals experienced spontaneous falling. Another cohort of animals was preconditioned with isoflurane for several days before being subjected to sGVS. Isoflurane preconditioning before sGVS did not prevent sGVS-induced hypotension or bradycardia, yet isoflurane preconditioning attenuated sGVS-induced cerebral blood flow reduction. The sGVS rat model mimics elements of human vasovagal syncope pathophysiology (hypotension, bradycardia, and decreased cerebral perfusion), including behavioral symptoms such as fatigue and altered balance. This study indicates that the sGVS rat model is similar to human vasovagal syncope and that therapies directed at preventing cerebral hypoperfusion may decrease syncopal episodes and reduce injuries from syncopal falls.
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Affiliation(s)
- Devin W. McBride
- Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, California, United States of America
| | - Cesar Reis
- Department of Anesthesiology, Loma Linda University, Loma Linda, California, United States of America
| | - Ethan Frank
- Loma Linda University School of Medicine, Loma Linda, California, United States of America
| | - Damon W. Klebe
- Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, California, United States of America
| | - John H. Zhang
- Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, California, United States of America
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, United States of America
| | - Richard Applegate
- Department of Anesthesiology, Loma Linda University, Loma Linda, California, United States of America
| | - Jiping Tang
- Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, California, United States of America
- * E-mail:
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Skoog J, Zachrisson H, Länne T, Lindenberger M. Reduced compensatory responses to maintain central blood volume during hypovolemic stress in women with vasovagal syncope. Am J Physiol Regul Integr Comp Physiol 2016; 312:R55-R61. [PMID: 27654398 DOI: 10.1152/ajpregu.00166.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/29/2016] [Accepted: 09/15/2016] [Indexed: 12/14/2022]
Abstract
Although vasovagal syncope (VVS) is a common clinical condition, the underlying pathophysiology is not fully understood. A decrease in cardiac output has recently been suggested as a factor in orthostatic VVS. The aim was to investigate compensatory mechanisms to maintain central blood volume and venous return during hypovolemic stress in women with VVS. Fourteen VVS women (25.7 ± 5.0 yr) and 15 matched controls (22.8 ± 3.2 yr) were investigated. Single-step and graded lower body negative pressure (LBNP) to presyncope were used to create hypovolemic stress. Peripheral mobilization of venous blood from the arm (capacitance response and net capillary fluid absorption) and lower limb blood pooling (calf capacitance response) were evaluated using a volumetric technique. Cardiovascular responses and plasma norepinephrine (P-NE) were measured. Resting P-NE was elevated in VVS women (P < 0.01). Despite a similar hypovolemic stimulus, the increase in P-NE was blunted (P < 0.01) and the maximal percent increase in total peripheral resistance was reduced (P < 0.05) during graded LBNP in VVS women. The arm capacitance response was slower (P < 0.05) and reduced in VVS women at higher levels of LBNP (P < 0.05). Capillary fluid absorption from extra- to intravascular space was reduced by ∼40% in VVS women (P < 0.05). Accordingly, the reduction in cardiac output was more pronounced (P < 0.05). In conclusion, in VVS women, mobilization of peripheral venous blood and net fluid absorption from tissue to blood during hypovolemic stress were decreased partly as a result of an attenuated vasoconstrictor response. This may seriously impede maintenance of cardiac output during hypovolemic stress and could contribute to the pathogenesis of VVS.
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Affiliation(s)
- Johan Skoog
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden;
| | - Helene Zachrisson
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Department of Clinical Physiology, Linköping University, Linköping, Sweden
| | - Toste Länne
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Department of Thoracic and Vascular Surgery, Linköping University, Linköping, Sweden; and
| | - Marcus Lindenberger
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Department of Cardiology, Linköping University, Linköping, Sweden
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Sheldon R, Raj SR, Rose MS, Morillo CA, Krahn AD, Medina E, Talajic M, Kus T, Seifer CM, Lelonek M, Klingenheben T, Parkash R, Ritchie D, McRae M, Sheldon R, Rose S, Ritchie D, McCrae M, Morillo C, Malcolm V, Krahn A, Spindler B, Medina E, Talajic M, Kus T, Langlois A, Lelonek M, Raj S, Seifer C, Gardner M, Romeo M, Poirier P, Simpson C, Abdollah H, Reynolds J, Dorian P, Birnie D, Giuffre M, Gilligan D, Benditt D, Sheldon R, Raj S, Rose M, Krahn A, Morillo C, Medina E. Fludrocortisone for the Prevention of Vasovagal Syncope. J Am Coll Cardiol 2016; 68:1-9. [DOI: 10.1016/j.jacc.2016.04.030] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/31/2016] [Accepted: 04/05/2016] [Indexed: 10/21/2022]
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Chaddha A, Wenzke KE, Brignole M, Wasmund SL, Page RL, Hamdan MH. The Role of the Baroreflex in Tilt Table Testing: Outcome and Type of Response. JACC Clin Electrophysiol 2016; 2:812-817. [PMID: 29759765 DOI: 10.1016/j.jacep.2016.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/29/2016] [Accepted: 05/12/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The purpose of this study was to better understand the role of the baroreflex in tilt-induced vasovagal syncope (VVS). BACKGROUND The role of the baroreflex in tilt-induced VVS remains controversial. The authors hypothesized that: 1) patients with positive tilt table test (TTT) results have greater baroreflex gain (BRG) compared with patients with negative TTT results; and 2) patients with tilt-induced asystole have greater BRG compared with patients without asystole. METHODS Using the sequence method, BRG measurements were obtained in 438 consecutive patients undergoing TTT. Two hundred sixty-eight patients (61%) had positive TTT results (mean age 50 ± 21 years; 34% men), and 170 patients (39%) had negative TTT results (mean age 48 ± 21 years; 35% men). RESULTS Mean BRG was significantly higher in patients with positive TTT results compared with those with negative TTT results (12.9 ± 6.0 ms/mm Hg vs. 11.5 ± 6.0 ms/mm Hg; p = 0.01). Among the 268 patients with positive TTT results, 23 (9%) had more than 3 s of asystole (mean age 37 ± 17; 30% men), and 245 patients had a mixed vasodepressor or cardioinhibitory response without asystole (mean age 51 ± 17 years; 34% men). Mean BRG was greater in patients with tilt-induced asystole (>3 s) compared with patients without asystole (15.3 ± 5.9 ms/mm Hg vs. 12.7 ± 5.9 ms/mm Hg; p = 0.03). CONCLUSIONS The results of this study demonstrate that baseline BRG was higher in patients with positive TTT results compared with those with negative TTT results, with greater values noted in patients with tilt-induced asystole (>3 s) compared with those without asystole.
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Affiliation(s)
- Ashish Chaddha
- Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Kevin E Wenzke
- Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Michele Brignole
- Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Stephen L Wasmund
- Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Richard L Page
- Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Mohamed H Hamdan
- Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
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Chaddha A, Rafanelli M, Brignole M, Sutton R, Wenzke KE, Wasmund SL, Page RL, Hamdan MH. The pathophysiologic mechanisms associated with hypotensive susceptibility. Clin Auton Res 2016; 26:261-8. [PMID: 27324399 DOI: 10.1007/s10286-016-0362-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/13/2016] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Patients with vasovagal syncope (VVS) and positive tilt table test (TTT) were not found to benefit from pacing in the ISSUE-3 trial despite the presence of spontaneous asystole during monitoring. "Hypotensive susceptibility" unmasked by TTT was reported as a possible explanation. The purpose of this study was to assess the pathophysiologic mechanisms associated with hypotensive susceptibility. METHODS 366 consecutive patients with the diagnosis of VVS who also had TTT were identified. Baroreflex gain (BRG) in addition to blood pressure (BP) and heart rate (HR) responses during the first 20 min of TTT were analyzed and compared between patients with positive TTT (n = 275, 75 %) and negative TTT (n = 91, 25 %). RESULTS The mean BRG was similar between the groups (12.5 ± 6.3 versus 12.4 ± 6.3 ms/mmHg, p = 0.72); however, an age-dependent decrease was noted (17.6 ± 4.8, 15.0 ± 6.0, 10.6 ± 4.2, 10.3 ± 6.4 and 9.9 ± 8.5 ms/mmHg for patients <21, 21-40, 41-60, 61-80 and >80 years old, respectively; p < 0.001). In addition, we saw a main effect of age on the type of response with a greater prevalence of a vasodepressor response in older subjects (p < 0.001). During the first 20 min of TTT, BP was similar in patients with tilt-positive VVS when compared with patients with tilt-negative VVS; however, HR was significantly lower. CONCLUSION BRG is similar in tilt-positive VVS patients when compared with tilt-negative VVS patients. An age-dependent decrease in BRG was noted with a higher prevalence of a vasodepressor response seen in older patients. The clinical significance of the blunted HR response in tilt-positive VVS remains to be determined.
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Affiliation(s)
- Ashish Chaddha
- Division of Cardiovascular Medicine, School of Medicine and Public Health, University of Wisconsin, H4/534 Clinical Science Center, 600 Highland Avenue, Madison, WI, 53792-3248, USA
| | - Martina Rafanelli
- Geriatric Cardiology and Medicine, University of Florence and Azienda Ospedaliero-Universitaria Careggi, Florence, Italy
| | | | - Richard Sutton
- National Heart and Lung Institute, Imperial College, London, UK
| | - Kevin E Wenzke
- Division of Cardiovascular Medicine, School of Medicine and Public Health, University of Wisconsin, H4/534 Clinical Science Center, 600 Highland Avenue, Madison, WI, 53792-3248, USA
| | - Stephen L Wasmund
- Division of Cardiovascular Medicine, School of Medicine and Public Health, University of Wisconsin, H4/534 Clinical Science Center, 600 Highland Avenue, Madison, WI, 53792-3248, USA
| | - Richard L Page
- Division of Cardiovascular Medicine, School of Medicine and Public Health, University of Wisconsin, H4/534 Clinical Science Center, 600 Highland Avenue, Madison, WI, 53792-3248, USA
| | - Mohamed H Hamdan
- Division of Cardiovascular Medicine, School of Medicine and Public Health, University of Wisconsin, H4/534 Clinical Science Center, 600 Highland Avenue, Madison, WI, 53792-3248, USA.
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Skoog J, Zachrisson H, Länne T, Lindenberger M. Slower Lower Limb Blood Pooling Increases Orthostatic Tolerance in Women with Vasovagal Syncope. Front Physiol 2016; 7:232. [PMID: 27378941 PMCID: PMC4906053 DOI: 10.3389/fphys.2016.00232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/30/2016] [Indexed: 11/28/2022] Open
Abstract
Background and Aim: Slower lower limb blood pooling and associated blunted sympathetic activation has been detected in healthy women prone to orthostatic syncope. Whether these findings are true also for patients with vasovagal syncope (VVS) is unknown. The aim was to investigate initial blood pooling time (poolingtime, time to 50% of total blood pooling) together with hemodynamic responses and orthostatic tolerance during lower body negative pressure (LBNP) in VVS and healthy controls. Methods and Results: Fourteen VVS women (25.7 ± 1.3 years) and 15 healthy women (22.8 ± 0.8 years) were subjected to single-step and graded LBNP to pre-syncope. Lower limb blood pooling (ml · 100 ml−1), poolingtime (s), hemodynamic responses and LBNP-tolerance were evaluated. LBNP induced comparable lower limb blood pooling in both groups (controls, 3.1 ± 0.3; VVS, 2.9 ± 0.3 ml · 100 ml−1, P = 0.70). In controls, shorter poolingtime correlated to higher LBNP-tolerance (r = –0.550, P < 0.05) as well as better maintained stroke volume (r = –0.698, P < 0.01) and cardiac output (r = –0.563, P < 0.05). In contrast, shorter poolingtime correlated to lower LBNP-tolerance in VVS (r = 0.821, P < 0.001) and larger decline in stroke volume (r = 0.611, P < 0.05). Furthermore, in controls, shorter poolingtime correlated to baroreflex-mediated hemodynamic changes during LBNP, e.g., increased vasoconstriction (P < 0.001). In VVS, poolingtime was not correlated with LBNP-induced baroreceptor unloading, but rather highly correlated to resting calf blood flow (P < 0.001). Conclusions: Shorter poolingtime seems to elicit greater sympathetic activation with a concomitant higher orthostatic tolerance in healthy women. The contrasting findings in VVS indicate a deteriorated vascular sympathetic control suggesting well-defined differences already in the initial responses during orthostatic stress.
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Affiliation(s)
- Johan Skoog
- Department of Medical and Health Sciences, Linköping UniversityLinköping, Sweden
- *Correspondence: Johan Skoog
| | - Helene Zachrisson
- Department of Clinical Physiology and Department of Medical and Health Sciences, Linköping UniversityLinköping, Sweden
| | - Toste Länne
- Department of Medical and Health Sciences, Linköping UniversityLinköping, Sweden
| | - Marcus Lindenberger
- Department of Cardiology and Department of Medical and Health Sciences, Linköping UniversityLinköping, Sweden
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Raj SR, Faris PD, Semeniuk L, Manns B, Krahn AD, Morillo CA, Benditt DG, Sheldon RS. Rationale for the Assessment of Metoprolol in the Prevention of Vasovagal Syncope in Aging Subjects Trial (POST5). Am Heart J 2016; 174:89-94. [PMID: 26995374 DOI: 10.1016/j.ahj.2016.01.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 01/20/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Vasovagal syncope (VVS) is a common problem associated with a poor quality of life, which improves when syncope frequency is reduced. Effective pharmacological therapies for VVS are lacking. Metoprolol is a β-adrenergic receptor antagonist that is ineffective in younger patients, but may benefit older (≥40 years) VVS patients. Given the limited therapeutic options, a placebo-controlled clinical trial of metoprolol for the prevention of VVS in older patients is needed. STRUCTURE OF STUDY The POST5 is a multicenter, international, randomized, placebo-controlled study of metoprolol in the prevention of VVS in patients ≥40 years old. The primary endpoint is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive metoprolol 25 to 100 mg BID or matching placebo, and followed up for 1 year. Secondary end points include syncope frequency, presyncope, quality of life, and cost analysis. Primary analysis will be intention to treat, with a secondary on-treatment analysis. POWER CALCULATIONS A sample size of 222, split equally between the groups achieves 85% power to detect a hazard rate of 0.3561 when the event rates are 50% and 30% in the placebo and metoprolol arms. Allowing for 10% dropout, we propose to enroll 248 patients. IMPLICATIONS This study will be the first adequately powered trial to determine whether metoprolol is effective in preventing VVS in patients ≥40 years. If effective, metoprolol may become the first line pharmacological therapy for these patients.
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Affiliation(s)
- Satish R Raj
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN.
| | | | - Lisa Semeniuk
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Braden Manns
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Andrew D Krahn
- Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, BC, Canada
| | | | - David G Benditt
- Cardiac Arrhythmia and Syncope Center, University of Minnesota, Minneapolis, MN
| | - Robert S Sheldon
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
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Raphan T, Cohen B, Xiang Y, Yakushin SB. A Model of Blood Pressure, Heart Rate, and Vaso-Vagal Responses Produced by Vestibulo-Sympathetic Activation. Front Neurosci 2016; 10:96. [PMID: 27065779 PMCID: PMC4814511 DOI: 10.3389/fnins.2016.00096] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/26/2016] [Indexed: 12/17/2022] Open
Abstract
Blood Pressure (BP), comprised of recurrent systoles and diastoles, is controlled by central mechanisms to maintain blood flow. Periodic behavior of BP was modeled to study how peak amplitudes and frequencies of the systoles are modulated by vestibular activation. The model was implemented as a relaxation oscillator, driven by a central signal related to Desired BP. Relaxation oscillations were maintained by a second order system comprising two integrators and a threshold element in the feedback loop. The output signal related to BP was generated as a nonlinear function of the derivative of the first state variable, which is a summation of an input related to Desired BP, feedback from the states, and an input from the vestibular system into one of the feedback loops. This nonlinear function was structured to best simulate the shapes of systoles and diastoles, the relationship between BP and Heart Rate (HR) as well as the amplitude modulations of BP and Pulse Pressure. Increases in threshold in one of the feedback loops produced lower frequencies of HR, but generated large pulse pressures to maintain orthostasis, without generating a VasoVagal Response (VVR). Pulse pressures were considerably smaller in the anesthetized rats than during the simulations, but simulated pulse pressures were lowered by including saturation in the feedback loop. Stochastic changes in threshold maintained the compensatory Baroreflex Sensitivity. Sudden decreases in Desired BP elicited non-compensatory VVRs with smaller pulse pressures, consistent with experimental data. The model suggests that the Vestibular Sympathetic Reflex (VSR) modulates BP and HR of an oscillating system by manipulating parameters of the baroreflex feedback and the signals that maintain the oscillations. It also shows that a VVR is generated when the vestibular input triggers a marked reduction in Desired BP.
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Affiliation(s)
- Theodore Raphan
- Department of Computer and Information Science, Institute for Neural and Intelligent Systems, Brooklyn College, City University of New York New York, NY, USA
| | - Bernard Cohen
- Department of Neurology, Icahn School of Medicine at Mount Sinai New York, NY, USA
| | - Yongqing Xiang
- Department of Computer and Information Science, Institute for Neural and Intelligent Systems, Brooklyn College, City University of New York New York, NY, USA
| | - Sergei B Yakushin
- Department of Neurology, Icahn School of Medicine at Mount Sinai New York, NY, USA
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Marchi A, Bari V, De Maria B, Cerutti S, Heusser K, Tank J, Jordan J, Barbic F, Furlan R, Porta A. Evaluation of the correlation between cardiac and sympathetic baroreflex sensitivity before orthostatic syncope. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:2063-6. [PMID: 26736693 DOI: 10.1109/embc.2015.7318793] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The study investigates the two different aspects of the baroreflex control resulting in two baroreflex sensitivity (BRS) indexes: i) sympathetic BRS (sBRS); ii) cardiac BRS (cBRS). sBRS was assessed as the slope of the regression line of the conditional probability of detecting a burst on the integrated muscle nerve sympathetic activity (MSNA) given an assigned diastolic arterial pressure (DAP) on DAP. cBRS was estimated from spontaneous heart period (HP) and systolic arterial pressure (SAP) via a spectral approach in the low (0.04-0-15 Hz) and high (0.15-0.5 Hz) frequency bands respectively. Both sBRS and cBRS were assessed in eight healthy subjects undergoing three experimental sessions: supine resting position (REST), 80 degrees head-up tilt test (TILT) and before the occurrence of pre-syncope symptoms (TILT_PRE). Results showed a decrease of both sBRS and cBRS during TILT and a baroreflex impairment during TILT_PRE. sBRS and cBRS were linearly correlated during TILT but became uncorrelated during TILT_PRE. Findings suggest a failure of both "baroreflexes" and their disassociation during TILT_PRE.
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Klemenc M, Štrumbelj E. Predicting the outcome of head-up tilt test using heart rate variability and baroreflex sensitivity parameters in patients with vasovagal syncope. Clin Auton Res 2015; 25:391-8. [PMID: 26546357 DOI: 10.1007/s10286-015-0318-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 09/18/2015] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of the study was to investigate whether a statistical model could be used for an early prediction of the head-up tilt test (HUTT) outcome from heart rate variability (HRV) and baroreflex sensitivity (BRS) data obtained during early stages of the HUTT. METHODS A modified Italian protocol was used for HUTT in 105 patients with a previous history of vasovagal syncope. Beat-to-beat heart rate and blood pressure were continuously recorded. Fast Fourier transformation was used for spectral analysis of HRV and a sequence technique for measuring the BRS. RESULTS Linear statistical models based on HRV and BRS data from the first 15 min of HUTT were no more accurate than always naively predicted majority class that a syncope will occur (average model out-of-sample accuracy 56.2 ± 5.1 % vs. majority class relative frequency 54.2 %). Even when HRV and BRS data from the first 30 min were used in the model, we did not obtain any predictions of meaningful practical value (75.0 ± 5.1 % accuracy vs. 72.2 % majority class). CONCLUSIONS While there are discernible and meaningful differences between HUTT-P and HUTT-N subjects, they are not sufficient to discriminate between the two groups and predict a syncope early in the HUTT. The results might improve with a larger set of subjects; however, we can conclude that it is not likely that syncope predictions of practical value can be obtained from aggregate HRV spectral analysis and BRS values.
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Affiliation(s)
- Matjaž Klemenc
- Department of Cardiology, General Hospital of Nova Gorica, Padlih borcev 13a, 5290, Šempeter Pri Gorici, Slovenia.
| | - Erik Štrumbelj
- Faculty of Computer Science, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia
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Carter JR, Goldstein DS. Sympathoneural and adrenomedullary responses to mental stress. Compr Physiol 2015; 5:119-46. [PMID: 25589266 DOI: 10.1002/cphy.c140030] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This concept-based review provides historical perspectives and updates about sympathetic noradrenergic and sympathetic adrenergic responses to mental stress. The topic of this review has incited perennial debate, because of disagreements over definitions, controversial inferences, and limited availability of relevant measurement tools. The discussion begins appropriately with Cannon's "homeostasis" and his pioneering work in the area. This is followed by mental stress as a scientific idea and the relatively new notions of allostasis and allostatic load. Experimental models of mental stress in rodents and humans are discussed, with particular attention to ethical constraints in humans. Sections follow on sympathoneural responses to mental stress, reactivity of catecholamine systems, clinical pathophysiologic states, and the cardiovascular reactivity hypothesis. Future advancement of the field will require integrative approaches and coordinated efforts between physiologists and psychologists on this interdisciplinary topic.
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Affiliation(s)
- Jason R Carter
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan Clinical Neurocardiology Section, Clinical Neurosciences Program, Division of Intramural Research, National Institutes of Health, Bethesda, Maryland
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Dehghan B, Sabri MR, Javanmard SH, Ahmadi AR, Mansourian M. Neurally mediated syncope: Is it really an endothelial dysfunction? Anatol J Cardiol 2015; 16:701-6. [PMID: 26680551 PMCID: PMC5331356 DOI: 10.5152/anatoljcardiol.2015.6325] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Syncope is a common problem in children and adolescents. Neurally mediated syncope is the most frequent form of this disorder. Although several studies have evaluated the pathophysiology of neurally mediated syncope, it is still not completely understood. METHODS We performed a cross-sectional study that included 27 patients aged 5-20 years with unexplained syncope and 30 healthy subjects as a control group. All subjects in both groups were assessed for endothelial function by investigating the following physical and chemical factors: flow-mediated dilation (FMD), intima-media thickness (IMT), circulating vascular cell adhesion molecule (VCAM), intercellular adhesion molecule (ICAM)], and endothelial leucocyte adhesion molecule (E-selectin), as well as epinephrine and norepinephrine. The data were statistically analyzed utilizing the SPSS 20.Significant differences between the groups in terms of mean scores were assessed using an independent sample t-test. RESULTS Mean FMD was significantly higher in the syncope case group than in the control group (p=0.028). There was no significant difference in IMT between the two groups; however, mean levels of ICAM (p=0.02) and VCAM (p=0.008) were significantly higher in the case group than in the control group. The levels of E-selectin also increased in the case group, but not to a statistically significant extent. The mean levels of epinephrine (p=0.01) were significantly lower in the case group than in the control group, and the level of norepinephrine serum decreased slightly, but not significantly, in the syncope patients. CONCLUSION Our results showed that an endothelial dysfunction or augmented endothelial function might exist in patients with neurally mediated syncope.
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Affiliation(s)
- Bahar Dehghan
- Department of Pediatric, Isfahan University of Medical Sciences; Isfahan-Iran.
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Sheldon RS, Grubb BP, Olshansky B, Shen WK, Calkins H, Brignole M, Raj SR, Krahn AD, Morillo CA, Stewart JM, Sutton R, Sandroni P, Friday KJ, Hachul DT, Cohen MI, Lau DH, Mayuga KA, Moak JP, Sandhu RK, Kanjwal K. 2015 heart rhythm society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope. Heart Rhythm 2015; 12:e41-63. [PMID: 25980576 DOI: 10.1016/j.hrthm.2015.03.029] [Citation(s) in RCA: 557] [Impact Index Per Article: 61.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Indexed: 01/14/2023]
Affiliation(s)
| | | | | | | | | | | | - Satish R Raj
- Libin Cardiovascular Institute of Alberta, Alberta, Canada; Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Andrew D Krahn
- Division of Cardiology, University of British Columbia, Vancouver, Canada
| | - Carlos A Morillo
- Department of Medicine, Cardiology Division, McMaster University Population Health Research Institute, Hamilton, Canada
| | | | - Richard Sutton
- National Heart and Lung Institute, Imperial College, London, United Kingdom
| | | | - Karen J Friday
- (13)Stanford University School of Medicine, Stanford, California
| | | | - Mitchell I Cohen
- Phoenix Children's Hospital, University of Arizona School of Medicine-Phoenix, Arizona Pediatric Cardiology/Mednax, Phoenix, Arizona
| | - Dennis H Lau
- Centre for Heart Rhythm Disorders, University of Adelaide; Department of Cardiology, Royal Adelaide Hospital; and South Australian Health and Medical Research Institute, Adelaide, Australia
| | | | - Jeffrey P Moak
- Children's National Medical Center, Washington, District of Columbia
| | - Roopinder K Sandhu
- University of Alberta, Department of Medicine, Division of Cardiology, Alberta, Canada
| | - Khalil Kanjwal
- Michigan Cardiovascular Institute, Central Michigan University, Saginaw, Michigan
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Lin J, Han Z, Li H, Chen SY, Li X, Liu P, Wang Y, Tang C, Du J, Jin H. Plasma C-type natriuretic peptide as a predictor for therapeutic response to metoprolol in children with postural tachycardia syndrome. PLoS One 2015; 10:e0121913. [PMID: 25811760 PMCID: PMC4374798 DOI: 10.1371/journal.pone.0121913] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/05/2015] [Indexed: 01/17/2023] Open
Abstract
POTS is a global public-health disease, but predictor for therapeutic response to metoprolol in children with POTS is lacking. This study was designed to investigate predictive value of plasma C-type natriuretic peptide (CNP) in the therapeutic efficacy of metoprolol on postural tachycardia syndrome (POTS) in children. Totally 34 children with POTS and 27 healthy children were included in the study. The head-up test or head-up tilt test was used to check heart rate and blood pressure from supine to upright in subjects. A double antibody (competitive) sandwich immunoluminometric assay was used to detect plasma CNP. Metoprolol was used to treat children with POTS. The difference in plasma concentrations of CNP between responders and non-responders was compared. An ROC curve was used to analyze plasma CNP to predict efficacy of metoprolol on POTS in children. Plasma CNP in children with POTS was significantly higher than that of healthy children [(51.9 ± 31.4) vs. (25.1 ± 19.1) pg/ml, P <0.001]. Plasma CNP in responders to metoprolol was significantly higher than non-responders [(59.1 ± 33.5) vs. (34.8 ± 16.7) pg/ml, P = 0.037] before treatment. The ROC curve showed that area under the curve was 0.821 (95% CI 0.642–0.999). The cut-off value of plasma CNP > 32.55 pg/ml yielded a sensitivity of 95.8% and specificity of 70% in predicting therapeutic efficacy of metoprolol on POTS children. Plasma CNP might serve as a useful predictor for the therapeutic efficacy of metoprolol on POTS in children.
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Affiliation(s)
- Jing Lin
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhenhui Han
- Department of Pediatrics, Kaifeng Children’s Hospital, Henan, China
| | - Hongxia Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Selena Ying Chen
- University of California San Diego, La Jolla, California, United States of America
| | - Xueying Li
- Department of Medical Statistics, Peking University First Hospital, Beijing, China
| | - Ping Liu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuli Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Chaoshu Tang
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
- Key Laboratory of Molecular Cardiology, Ministry of Education, Beijing, China
| | - Junbao Du
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hongfang Jin
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- * E-mail:
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Barbic F, Heusser K, Marchi A, Zamunér AR, Gauger P, Tank J, Jordan J, Diedrich A, Robertson D, Dipaola F, Achenza S, Porta A, Furlan R. Cardiovascular parameters and neural sympathetic discharge variability before orthostatic syncope: role of sympathetic baroreflex control to the vessels. Physiol Meas 2015; 36:633-41. [PMID: 25798786 DOI: 10.1088/0967-3334/36/4/633] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We tested the hypothesis that altered sympathetic baroreceptor control to the vessels (svBRS) and disrupted coupling between blood pressure (BP) fluctuations and muscle sympathetic activity (MSNA) discharge pattern in the low frequency band (LF, around 0.1 Hz) precede vasovagal syncope. Seven healthy males underwent ECG, BP, respiratory, and MSNA recordings at baseline (REST) and during a 15 min 80° head-up tilt, followed by a -10 mmHg step wise increase of lower body negative pressure up to presyncope. Spectral and coherence analyses of systolic arterial pressure (SAP) and MSNA variability provided the indexes of vascular sympathetic modulation, LFSAP, and of the linear coupling between MSNA and SAP in the low frequency band (around 0.1 Hz), K(2)MSNA-SAP(LF). svBRS was assessed as the slope of the regression line between MSNA and diastolic arterial pressure (DAP). Data were analyzed at REST, during asymptomatic and presyncope periods of tilt. svBRS declined during presyncope period compared to REST and asymptomatic tilt. The presyncope period was characterized by a decrease of RR interval, LFMSNA, LFSAP, and K(2)MSNA-SAP(LF) values compared to the asymptomatic one, whereas MSNA burst rate was unchanged. The reduction of svBRS producing an altered coupling between MSNA and SAP variability at 0.1 Hz, may provoke circulatory changes leading to presyncope.
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Affiliation(s)
- Franca Barbic
- Internal Medicine, Humanitas Clinical and Research Center, Rozzano, BIOMETRA Department, University of Milan, Italy
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Lindenberger M, Länne T. Slower lower limb blood pooling in young women with orthostatic intolerance. Exp Physiol 2015; 100:2-11. [PMID: 25557726 DOI: 10.1113/expphysiol.2014.082867] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 10/20/2014] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Orthostatic stress is mostly caused by venous blood pooling in the lower limbs. Venous distension elicits sympathetic responses, and increased distension speed enhances the cardiovascular response. We examine whether lower limb blood pooling rate during lower body negative pressure is linked to orthostatic intolerance. What is the main finding and its importance? A similar amount of blood was pooled in the lower limb, but at a slower rate in women who developed signs of orthostatic intolerance. The difference in blood pooling rate increased with orthostatic stress and was most prominent at a presyncope-inducing level of lower body negative pressure. The findings have implications for the pathophysiology as well as treatment of orthostatic intolerance. Vasovagal syncope is common in young women, but its aetiology remains elusive. Orthostatic stress-induced lower limb blood pooling is linked with central hypovolaemia and baroreceptor unloading. Venous distension in the arm elicits a sympathetic response, which is enhanced with more rapid distension. Our aim was to study both the amount and the speed of lower limb pooling during orthostatic stress and its effects on compensatory mechanisms to maintain cardiovascular homeostasis in women with orthostatic intolerance. Twenty-seven healthy women, aged 20-27 years, were subjected to a lower body negative pressure (LBNP) of 11-44 mmHg. Five women developed symptoms of vasovagal syncope (orthostatic intolerant) and were compared with the remaining women, who tolerated LBNP well (orthostatic tolerant). Lower limb blood pooling, blood flow and compensatory mobilization of venous capacitance blood were measured. Lower body negative pressure induced equal lower limb blood pooling in both groups, but at a slower rate in orthostatic intolerant women (e.g. time to 50% of total blood pooling, orthostatic intolerant 44 ± 7 s and orthostatic tolerant 26 ± 2 s; P < 0.001). At presyncope-inducing LBNP, the mobilization of venous capacitance blood was both reduced (P < 0.05) and much slower in orthostatic intolerant women (P = 0.0007). Orthostatic intolerant women elicited blunted arterial vasoconstriction at low-grade LBNP, activating only cardiopulmonary baroreceptors, while orthostatic tolerant women responded with apparent vasoconstriction (P < 0.0001). In conclusion, slower lower limb blood pooling could contribute to orthostatic intolerance in women. Mobilization of venous capacitance blood from the peripheral to the central circulation was both slower and decreased; furthermore, reduced cardiopulmonary baroreceptor sensitivity was found in women who developed orthostatic intolerance. Further studies including women who experience syncope in daily life are needed.
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Affiliation(s)
- Marcus Lindenberger
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden; Department of Cardiology, County Council of Östergötland, Linköping, Sweden
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Goldstein DS. Concepts of scientific integrative medicine applied to the physiology and pathophysiology of catecholamine systems. Compr Physiol 2014; 3:1569-610. [PMID: 24265239 DOI: 10.1002/cphy.c130006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review presents concepts of scientific integrative medicine and relates them to the physiology of catecholamine systems and to the pathophysiology of catecholamine-related disorders. The applications to catecholamine systems exemplify how scientific integrative medicine links systems biology with integrative physiology. Concepts of scientific integrative medicine include (i) negative feedback regulation, maintaining stability of the body's monitored variables; (ii) homeostats, which compare information about monitored variables with algorithms for responding; (iii) multiple effectors, enabling compensatory activation of alternative effectors and primitive specificity of stress response patterns; (iv) effector sharing, accounting for interactions among homeostats and phenomena such as hyperglycemia attending gastrointestinal bleeding and hyponatremia attending congestive heart failure; (v) stress, applying a definition as a state rather than as an environmental stimulus or stereotyped response; (vi) distress, using a noncircular definition that does not presume pathology; (vii) allostasis, corresponding to adaptive plasticity of feedback-regulated systems; and (viii) allostatic load, explaining chronic degenerative diseases in terms of effects of cumulative wear and tear. From computer models one can predict mathematically the effects of stress and allostatic load on the transition from wellness to symptomatic disease. The review describes acute and chronic clinical disorders involving catecholamine systems-especially Parkinson disease-and how these concepts relate to pathophysiology, early detection, and treatment and prevention strategies in the post-genome era.
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Affiliation(s)
- David S Goldstein
- Clinical Neurocardiology Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
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47
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Barbic F, Casazza G, Zamunér AR, Costantino G, Orlandi M, Dipaola F, Capitanio C, Achenza S, Sheldon R, Furlan R. Driving and Working with Syncope. Auton Neurosci 2014; 184:46-52. [DOI: 10.1016/j.autneu.2014.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/28/2014] [Accepted: 05/06/2014] [Indexed: 11/25/2022]
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Alboni P, Alboni M. Vasovagal Syncope As A Manifestation Of An Evolutionary Selected Trait. J Atr Fibrillation 2014; 7:1035. [PMID: 27957092 PMCID: PMC5135249 DOI: 10.4022/jafib.1035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 08/19/2014] [Accepted: 08/20/2014] [Indexed: 01/10/2023]
Abstract
Some observations suggest that typical (emotional or orthostatic) vasovagal syncope (VVS) is not a disease, but rather a manifestation of a non-pathological trait. We conducted an extensive bibliographic research on the vasovagal reactions in animals, including humans, in order to investigate the possible factors that may explain the origin and evolution of VVS. We found two processes which appear relevant for the investigation of VVS evolution: fear/threat bradycardia (alarm bradycardia) in animals, mainly during tonic immobility and vasovagal reflex during hemorrhagic shock (thoracic hypovolemia) both in animals and humans. The available data suggest that VVS in humans, alarm bradycardia in animals and the vasovagal reflex during hemorrhagic shock share the same physiological mechanisms and that is indicative of a common evolutionary root. However, during the vasovagal reflex loss of consciousness occurs in humans, but it is absent (or extremely rare) in animals. That can be explained as a by-product due to the erect position and the large brain evolved in our species. If the vasovagal reflex persisted for millions of years along the vertebrates evolutionary history, we can reasonably assume that it has a function and it is not harmful. It could be neutral or beneficial, but the available data suggest it is beneficial; likely, it evolved as an advantageous response to stressful and possibly dangerous heart conditions. Emotional or orthostatic vasovagal reflex is preceded by enhanced sympathetic activity, which is harmful and possibly dangerous. The transient inhibition of the sympathetic system, together with activation of the vagal tone , characterizes VVS. The consequent slowing of the heart rate induced by the vasovagal reflex may constitute a beneficial break of the cardiac pump, thereby reducing myocardial oxygen consumption. We suggest that typical VVS should be regarded as a selected response, which probably evolved in the ancient past as a defense mechanism of the organism within some ancestral group(s) of vertebrates.
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Affiliation(s)
- Paolo Alboni
- Section of Cardiology and Syncope Unit, Ospedale Privato Quisisana, Ferrara, Italy
| | - Marco Alboni
- Department of Zoology and Anthropology, University of Sassari, Italy
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Lambert E, Lambert GW. Sympathetic dysfunction in vasovagal syncope and the postural orthostatic tachycardia syndrome. Front Physiol 2014; 5:280. [PMID: 25120493 PMCID: PMC4112787 DOI: 10.3389/fphys.2014.00280] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 07/08/2014] [Indexed: 01/29/2023] Open
Abstract
Orthostatic intolerance is the inability to tolerate the upright posture and is relieved by recumbence. It most commonly affects young women and has a major impact on quality of life and psychosocial well-being. Several forms of orthostatic intolerance have been described. The most common one is the recurrent vasovagal syncope (VVS) phenotype which presents as a transient and abrupt loss of consciousness and postural tone that is followed by rapid recovery. Another common type of orthostatic intolerance is the postural orthostatic tachycardia syndrome (POTS) which is characterized by an excessive rise in heart rate upon standing and is associated with symptoms of presyncope such as light-headedness, fatigue, palpitations, and nausea. Maintenance of arterial pressure under condition of reduced central blood volume during the orthostasis is accomplished in large part through sympathetic efferent nerve traffic to the peripheral vasculature. Therefore sympathetic nervous system (SNS) dysfunction is high on the list of possible contributors to the pathophysiology of orthostatic intolerance. Investigations into the role of the SNS in orthostatic intolerance have yielded mixed results. This review outlines the current knowledge of the function of the SNS in both VVS and POTS.
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Affiliation(s)
- Elisabeth Lambert
- Human Neurotransmitters Laboratory, Baker IDI Heart and Diabetes Institute Melbourne, VIC, Australia ; Departments of Physiology, Monash University Clayton, VIC, Australia
| | - Gavin W Lambert
- Human Neurotransmitters Laboratory, Baker IDI Heart and Diabetes Institute Melbourne, VIC, Australia ; Faculty of Medicine, Nursing and Health Sciences, Monash University Clayton, VIC, Australia
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Pathophysiology of neurally mediated syncope: Role of cardiac output and total peripheral resistance. Auton Neurosci 2014; 184:24-6. [PMID: 25081417 DOI: 10.1016/j.autneu.2014.07.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/07/2014] [Accepted: 07/09/2014] [Indexed: 11/24/2022]
Abstract
Syncope is a common clinical condition occurring even in otherwise healthy people without underlying cardiovascular disease. Neurally mediated syncope is by far the most common cause of syncope in individuals without any structural heart disease. Based on traditional wisdom, loss of sympathetic tone with relaxation of vascular smooth muscle is the key mechanism underlying the pathophysiology of syncope, especially in patients without an acute decrease in heart rate. However, this concept has recently been challenged. Some microneurographic studies indicate that sympathetic withdrawal may not always be a prerequisite even for the development of classic "vasodepressor" forms of syncope. Conversely, a decrease in cardiac output appears to be a determinant factor for syncope in most circumstances. This article reviews the relative contribution of cardiac output versus sympathetic vasoconstriction in neurally mediated syncope in otherwise healthy individuals. It is suggested that a moderate to severe fall in cardiac output with or without vasodilatation may contribute to syncope.
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