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Orthostatic intolerance

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https://www.readbyqxmd.com/read/29333725/chemoreflex-function-and-brain-blood-flow-during-upright-posture-in-men-and-women
#1
Christopher Hazlett, Heather Edgell
Orthostatic intolerance is more common in women than men, and some studies have found that women in the early follicular (EF) phase of the menstrual cycle experience the greatest feelings of lightheadedness. Chemoreflex function while supine or upright was investigated to determine the potential contribution of ventilatory control to these phenomena. Men (n = 13) and women (n = 14) were tested while supine and 70° upright (head-up tilt [HUT]) and given: (1) normoxia or (2) hypercapnia (5% CO2 ). Women were tested during the EF phase (days 2-5) and the midluteal phase (ML; days 18-24)...
January 2018: Physiological Reports
https://www.readbyqxmd.com/read/29331491/investigating-the-relationship-between-cardiac-interoception-and-autonomic-cardiac-control-using-a-predictive-coding-framework
#2
Andrew P Owens, Karl J Friston, David A Low, Christopher J Mathias, Hugo D Critchley
Predictive coding models, such as the 'free-energy principle' (FEP), have recently been discussed in relation to how interoceptive (afferent visceral feedback) signals update predictions about the state of the body, thereby driving autonomic mediation of homeostasis. This study appealed to 'interoceptive inference', under the FEP, to seek new insights into autonomic (dys)function and brain-body integration by examining the relationship between cardiac interoception and autonomic cardiac control in healthy controls and patients with forms of orthostatic intolerance (OI); to (i) seek empirical support for interoceptive inference and (ii) delineate if this relationship was sensitive to increased interoceptive prediction error in OI patients during head-up tilt (HUT)/symptom provocation...
January 9, 2018: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/29330767/ivabradine-for-the-treatment-of-postural-orthostatic-tachycardia-syndrome-a-systematic-review
#3
REVIEW
Megan E Gee, Alicia K Watkins, Jamie N Brown, Emily J A Young
INTRODUCTION: Postural orthostatic tachycardia syndrome (POTS) impacts millions of patients, but there is currently no gold standard treatment for this condition. Ivabradine is a novel heart rate (HR) lowering agent that acts on the sinoatrial node cells by selectively inhibiting the If-current. OBJECTIVE: The objective of this systematic review is to evaluate the evidence for the efficacy and safety of ivabradine for the treatment of POTS. METHODS: MEDLINE (from 1956 to August 2017) and EMBASE (from 1957 to August 2017) were queried with the following search term: "postural orthostatic tachycardia syndrome" OR "postural tachycardia syndrome" OR "chronic orthostatic intolerance" AND "ivabradine...
January 12, 2018: American Journal of Cardiovascular Drugs: Drugs, Devices, and Other Interventions
https://www.readbyqxmd.com/read/29295851/proteomic-profiling-for-cardiovascular-biomarker-discovery-in-orthostatic-hypotension
#4
Madeleine Johansson, Fabrizio Ricci, Nay Aung, Richard Sutton, Olle Melander, Artur Fedorowski
Orthostatic hypotension (OH) has been linked with higher incidence of cardiovascular disease, but little is known about the mechanisms behind this association. We aimed to identify cardiovascular disease biomarkers associated with OH through a proteomic profiling approach. Seven hundred seventy-eight patients with unexplained syncope or orthostatic intolerance underwent head-up tilt test and supine blood samples. Of these, 220 met diagnostic criteria of OH, and 179 demonstrated normal hemodynamic response during head-up tilt test...
January 2, 2018: Hypertension
https://www.readbyqxmd.com/read/29222399/pediatric-disorders-of-orthostatic-intolerance
#5
REVIEW
Julian M Stewart, Jeffrey R Boris, Gisela Chelimsky, Phillip R Fischer, John E Fortunato, Blair P Grubb, Geoffrey L Heyer, Imad T Jarjour, Marvin S Medow, Mohammed T Numan, Paolo T Pianosi, Wolfgang Singer, Sally Tarbell, Thomas C Chelimsky
Orthostatic intolerance (OI), having difficulty tolerating an upright posture because of symptoms or signs that abate when returned to supine, is common in pediatrics. For example, ∼40% of people faint during their lives, half of whom faint during adolescence, and the peak age for first faint is 15 years. Because of this, we describe the most common forms of OI in pediatrics and distinguish between chronic and acute OI. These common forms of OI include initial orthostatic hypotension (which is a frequently seen benign condition in youngsters), true orthostatic hypotension (both neurogenic and nonneurogenic), vasovagal syncope, and postural tachycardia syndrome...
January 2018: Pediatrics
https://www.readbyqxmd.com/read/29212807/the-independent-and-interactive-effects-of-incremental-heat-strain-orthostatic-stress-and-mild-hypohydration-on-cerebral-perfusion
#6
Rebekah A I Lucas, Luke C Wilson, Philip N Ainslie, Jui-Lin Fan, Kate N Thomas, James D Cotter
The purpose of this study was to identify the dose-dependent effects of heat strain and orthostasis (via lower-body negative pressure; LBNP), with and without mild hypohydration, on systemic function and cerebral perfusion. Eleven males (Mean ±SD: 27 ±7 y; body mass 77 ±6 kg), resting supine in a water-perfused suit, underwent progressive passive heating [0.5°C increments in core temperature (Tc, oesophageal to +2.0°C)] whilst euhydrated (EUH) or hypohydrated (HYPO, 1.5-2% body mass deficit). At each thermal state, mean cerebral artery blood velocity (MCAvmean, Transcranial Doppler), partial pressure of end-tidal carbon dioxide (PETCO2), heart rate (HR) and mean arterial blood pressure (MAP, photoplethysmography) were measured continuously during LBNP (0, -15, -30, -45 mm Hg)...
December 6, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/29190150/intravenous-saline-administration-in-patients-with-severe-acquired-brain-injury-and-orthostatic-intolerance-for-tilt-table-mobilization
#7
Christian Riberholt, Niels Olesen, Peter Hovind, Jesper Mehlsen, Tue Hvass Petersen
PRIMARY OBJECTIVE: This study aimed to investigate the effect of intravenous saline administration on orthostatic hypotension (OH) during head up tilt (HUT) and the change in the renin-angiotensin-aldosterone system before and after HUT in patients with severe acquired brain injury (ABI). RESEARCH DESIGN: The study is designed as an observational study. METHODS AND PROCEDURES: Fourteen patients with ABI, low level of consciousness and OH were monitored before, during and after HUT with non-invasive beat-to-beat blood pressure measurement, and transcranial Doppler determination of middle cerebral artery blood flow velocity...
November 30, 2017: Brain Injury: [BI]
https://www.readbyqxmd.com/read/29176950/cardiovascular-and-cutaneous-responses-to-the-combination-of-alcohol-and-soft-drinks-the-way-to-orthostatic-intolerance
#8
Claire Maufrais, Nathalie Charriere, Jean-Pierre Montani
Aim: Acute ingestion of alcohol is often accompanied by cardiovascular dysregulation, malaise and even syncope. The full hemodynamic and cutaneous responses to the combination of alcohol and sugar (i.e., alcopops), a common combination in young people, and the mechanisms for the propensity to orthostatic intolerance are not well established. Thus, the purpose of this study was to evaluate the cardiovascular and cutaneous responses to alcopops in young subjects. Methods: Cardiovascular and cutaneous responses were assessed in 24 healthy young subjects (12 men, 12 women) sitting comfortably and during prolonged active standing with a 30-min baseline and 130 min following ingestion of 400 mL of either: water, water + 48 g sugar, water + vodka (1...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29166666/evaluating-the-efficacy-of-an-active-compression-brace-on-orthostatic-cardiovascular-responses
#9
Hadi Moein, Ramandeep Jhalli, Andrew P Blaber, Victoria E Claydon, Carlo Menon
Orthostatic intolerance, one of the principle causes of syncope, can occur secondary to concomitant venous pooling and enhanced capillary filtration. We aimed to evaluate a prototype portable calf active compression brace (ACB) designed to improve orthostatic haemodynamic control. Fourteen healthy volunteers participated in a randomized, placebo controlled, cross-over, double-blind study. Testing consisted of head-upright tilting and walking on a treadmill conducted on two consecutive days with a pair of ACBs wrapped around both calves...
2017: PloS One
https://www.readbyqxmd.com/read/29163185/orthostatic-intolerance-in-older-persons-etiology-and-countermeasures
#10
REVIEW
Nandu Goswami, Andrew P Blaber, Helmut Hinghofer-Szalkay, Jean-Pierre Montani
Orthostatic challenge produced by upright posture may lead to syncope if the cardiovascular system is unable to maintain adequate brain perfusion. This review outlines orthostatic intolerance related to the aging process, long-term bedrest confinement, drugs, and disease. Aging-associated illness or injury due to falls often leads to hospitalization. Older patients spend up to 83% of hospital admission lying in bed and thus the consequences of bedrest confinement such as physiological deconditioning, functional decline, and orthostatic intolerance represent a central challenge in the care of the vulnerable older population...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29075195/falls-and-fall-prevention-in-older-persons-geriatrics-meets-spaceflight
#11
REVIEW
Nandu Goswami
This paper provides a general overview of key physiological consequences of microgravity experienced during spaceflight and of important parallels and connections to the physiology of aging. Microgravity during spaceflight influences cardiovascular function, cerebral autoregulation, musculoskeletal, and sensorimotor system performance. A great deal of research has been carried out to understand these influences and to provide countermeasures to reduce the observed negative consequences of microgravity on physiological function...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29056408/effect-of-gravitational-gradients-on-cardiac-filling-and-performance
#12
Kazuaki Negishi, Allen G Borowski, Zoran B Popović, Neil L Greenberg, David S Martin, Michael W Bungo, Benjamin D Levine, James D Thomas
BACKGROUND: Gravity affects every aspect of cardiac performance. When gravitational gradients are at their greatest on Earth (i.e., during upright posture), orthostatic intolerance may ensue and is a common clinical problem that appears to be exacerbated by the adaptation to spaceflight. We sought to elucidate the alterations in cardiac performance during preload reduction with progressive upright tilt that are relevant both for space exploration and the upright posture, particularly the preload dependence of various parameters of cardiovascular performance...
October 19, 2017: Journal of the American Society of Echocardiography
https://www.readbyqxmd.com/read/29045956/-co-morbidity-of-vasovagal-syncope-and-postural-tachycardia-syndrome-with-allergic-diseases-in-children
#13
Y Liao, Q Y Zhang, H X Li, Y L Wang, P Liu, J B DU
OBJECTIVE: To explore the clinical characteristics of the co-morbidity of vasovagal syncope (VVS) and postural tachycardia syndrome (POTS) with allergic diseases in children. METHODS: A re-trospective analysis was launched to summarize the clinical data of children with VVS and POTS. They were divided into allergic group and non-allergic group according to the history of allergic diseases. The participants' clinical characteristics were compared between allergic group and non-allergic group using independent sample t test or rank sum test; composition comparisons were completed by Chi-square test...
October 18, 2017: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
https://www.readbyqxmd.com/read/29036615/monitoring-of-cerebral-oximetry-during-head-up-tilt-test-in-adults-with-history-of-syncope-and-orthostatic-intolerance
#14
E Bachus, H Holm, V Hamrefors, O Melander, R Sutton, M Magnusson, A Fedorowski
Aims: We applied near-infrared-spectroscopy (NIRS) to measure absolute frontal cerebral tissue oxygen saturation (SctO2) during head-up tilt test (HUT) in patients investigated for unexplained syncope. Methods and results: Synchronized non-invasive beat-to-beat haemodynamic monitoring, ECG, SctO2 (NIRS; normal range: 60-80%), and peripheral oxygen saturation (left hand, SpO2) were applied during HUT in a random sample of patients with unexplained syncope. Tracings of 54 patients (mean-age: 55 ± 19 years, 39% male) with negative HUT, vasovagal syncope (VVS), or orthostatic hypotension (OH) were analysed...
September 28, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29025902/relative-contributions-of-systemic-hemodynamic-variables-to-cerebral-autoregulation-during-orthostatic-stress
#15
Hisao Yoshida, Jason W Hamner, Keita Ishibashi, Can Ozan Tan
Postural changes impair the ability of the cerebrovasculature to buffer against dynamic pressure fluctuations, but the mechanisms underlying this impairment have not been elucidated. We hypothesized that autoregulatory impairment may reflect the impact of static central volume shifts on hemodynamic factors other than arterial pressure (AP). In 14 young volunteers, we assessed the relation of fluctuations in cerebral blood flow (CBF) to those in AP, cardiac output, and CO2, during oscillatory lower body pressure (LBP) (±20 mmHg at 0...
October 12, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28983659/cardiac-and-peripheral-vasomotor-autonomic-functions-in-late-onset-transthyretin-val30met-familial-amyloid-polyneuropathy
#16
Haruki Koike, Tomohiko Nakamura, Atsushi Hashizume, Ryoji Nishi, Shohei Ikeda, Yuichi Kawagashira, Masahiro Iijima, Masahisa Katsuno, Gen Sobue
The objective of this study was to systematically investigate cardiac and peripheral vasomotor autonomic functions in late-onset transthyretin Val30Met familial amyloid polyneuropathy (FAP ATTR Val30Met) patients from non-endemic areas. The coefficient of variation of R-R intervals (CVR-R), responses to the Valsalva manoeuvre, head-up tilt test with impedance cardiography, noradrenaline infusion test, and (123)I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy were assessed in eight patients. Although only four patients manifested orthostatic hypotension during the head-up tilt test, CVR-R, responses to the Valsalva manoeuvre, and myocardial MIBG uptake indicated a higher prevalence of cardiac sympathetic and parasympathetic dysfunction...
November 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28955298/subjective-cognitive-fatigue-and-autonomic-abnormalities-in-multiple-sclerosis-patients
#17
Carina Sander, Helmut Hildebrandt, Hans-Peter Schlake, Paul Eling, Katrin Hanken
BACKGROUND: Cognitive fatigue and autonomic abnormalities are frequent symptoms in MS. Our model of MS-related fatigue assumes a shared neural network for cognitive fatigue and autonomic failures, i.e., aberrant vagus nerve activity induced by inflammatory processes. Therefore, they should occur in common. OBJECTIVE: To explore the relationship between cognitive fatigue and autonomic symptoms in MS patients, using self-reported questionnaires. METHODS: In 95 MS patients, cognitive fatigue was assessed with the Fatigue Scale for Motor and Cognitive Functions and autonomic abnormalities with the Composite Autonomic Symptom Scale-31 (COMPASS-31)...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28955249/altered-venous-function-during-long-duration-spaceflights
#18
Jacques-Olivier Fortrat, Ana de Holanda, Kathryn Zuj, Guillemette Gauquelin-Koch, Claude Gharib
Aims: Venous adaptation to microgravity, associated with cardiovascular deconditioning, may contribute to orthostatic intolerance following spaceflight. The aim of this study was to analyze the main parameters of venous hemodynamics with long-duration spaceflight. Methods: Venous plethysmography was performed on 24 cosmonauts before, during, and after spaceflights aboard the International Space Station. Venous plethysmography assessed venous filling and emptying functions as well as microvascular filtration, in response to different levels of venous occlusion pressure...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28948941/vitamin-d-and-cardiovascular-risk-in-children
#19
REVIEW
Wen-Rui Xu, Hong-Fang Jin, Jun-Bao Du
OBJECTIVE: Vitamin D is a group of fat-soluble molecules that are structurally similar to steroids. Emerging data have led to the hypothesis that Vitamin D plays a role in the regulation of many physiological processes beyond calcium and phosphorus homeostasis. With this review, we aimed to summarize the changes in Vitamin D levels in children with cardiovascular diseases based on the literature. In addition, we also reviewed the potential mechanisms underlying cardiovascular diseases associated with Vitamin D deficiency or insufficiency...
September 22, 2017: Chinese Medical Journal
https://www.readbyqxmd.com/read/28934906/autonomic-symptoms-in-patients-with-moderate-and-severe-chronic-obstructive-pulmonary-disease
#20
Jibril Mohammed, Eric Derom, Inge De Wandele, Lies Rombaut, Patrick Calders
OBJECTIVES: A synoptic description of the autonomic symptoms profile (ASP) of patients with COPD is not available. Therefore, we aimed to provide an overview of autonomic symptoms and its associates in COPD. METHODS: We evaluated 89 subjects with COPD (65 ± 7.3 years; 66 males; GOLD II-IV) with an equal number of age- and sex-matched control subjects by means of the composite autonomic symptom score (COMPASS 31) questionnaire, which assesses autonomic symptoms across six domains (orthostatic intolerance, vasomotor, secretomotor, gastrointestinal, urinary and pupillomotor)...
September 22, 2017: Acta Clinica Belgica
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