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Javaheri S, Javaheri S, Somers VK, Gozal D, Mokhlesi B, Mehra R, McNicholas WT, Zee PC, Campos-Rodriguez F, Martinez-Garcia MA, Cistulli P, Malhotra A. Interactions of Obstructive Sleep Apnea With the Pathophysiology of Cardiovascular Disease, Part 1: JACC State-of-the-Art Review. J Am Coll Cardiol 2024; 84:1208-1223. [PMID: 39293884 DOI: 10.1016/j.jacc.2024.02.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 09/20/2024]
Abstract
The American Heart Association considers sleep health an essential component of cardiovascular health, and sleep is generally a time of cardiovascular quiescence, such that any deviation from normal sleep may be associated with adverse cardiovascular consequences. Many studies have shown that both impaired quantity and quality of sleep, particularly with obstructive sleep apnea (OSA) and comorbid sleep disorders, are associated with incident cardiometabolic consequences. OSA is associated with repetitive episodes of altered blood gases, arousals, large negative swings in intrathoracic pressures, and increased sympathetic activity. Recent studies show that OSA is also associated with altered gut microbiota, which could contribute to increased risk of cardiovascular disease. OSA has been associated with hypertension, atrial fibrillation, heart failure, coronary artery disease, stroke, and excess cardiovascular mortality. Association of OSA with chronic obstructive lung disease (overlap syndrome) and morbid obesity (obesity hypoventilation syndrome) increases the odds of mortality.
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Affiliation(s)
| | - Sogol Javaheri
- TriHealth Bethesda North Hospital, Cincinnati, Ohio, USA
| | | | - David Gozal
- TriHealth Bethesda North Hospital, Cincinnati, Ohio, USA
| | - Babak Mokhlesi
- TriHealth Bethesda North Hospital, Cincinnati, Ohio, USA
| | - Reena Mehra
- TriHealth Bethesda North Hospital, Cincinnati, Ohio, USA
| | | | - Phyllis C Zee
- TriHealth Bethesda North Hospital, Cincinnati, Ohio, USA
| | | | | | - Peter Cistulli
- TriHealth Bethesda North Hospital, Cincinnati, Ohio, USA
| | - Atul Malhotra
- TriHealth Bethesda North Hospital, Cincinnati, Ohio, USA
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2
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Valente R, Cordeiro M, Pinto B, Machado A, Alves F, Sousa-Pinto I, Ruivo R, Castro LFC. Alterations of pleiotropic neuropeptide-receptor gene couples in Cetacea. BMC Biol 2024; 22:186. [PMID: 39218857 PMCID: PMC11367936 DOI: 10.1186/s12915-024-01984-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/15/2024] [Indexed: 09/04/2024] Open
Abstract
BACKGROUND Habitat transitions have considerable consequences in organism homeostasis, as they require the adjustment of several concurrent physiological compartments to maintain stability and adapt to a changing environment. Within the range of molecules with a crucial role in the regulation of different physiological processes, neuropeptides are key agents. Here, we examined the coding status of several neuropeptides and their receptors with pleiotropic activity in Cetacea. RESULTS Analysis of 202 mammalian genomes, including 41 species of Cetacea, exposed an intricate mutational landscape compatible with gene sequence modification and loss. Specifically for Cetacea, in the 12 genes analysed we have determined patterns of loss ranging from species-specific disruptive mutations (e.g. neuropeptide FF-amide peptide precursor; NPFF) to complete erosion of the gene across the cetacean stem lineage (e.g. somatostatin receptor 4; SSTR4). CONCLUSIONS Impairment of some of these neuromodulators may have contributed to the unique energetic metabolism, circadian rhythmicity and diving response displayed by this group of iconic mammals.
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Affiliation(s)
- Raul Valente
- CIMAR/CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, 4450-208, Matosinhos, S/N, Portugal
- FCUP - Department of Biology, Faculty of Sciences, University of Porto (U. Porto), Rua Do Campo Alegre, Porto, Portugal
| | - Miguel Cordeiro
- CIMAR/CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, 4450-208, Matosinhos, S/N, Portugal
| | - Bernardo Pinto
- CIMAR/CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, 4450-208, Matosinhos, S/N, Portugal
- FCUP - Department of Biology, Faculty of Sciences, University of Porto (U. Porto), Rua Do Campo Alegre, Porto, Portugal
| | - André Machado
- CIMAR/CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, 4450-208, Matosinhos, S/N, Portugal
- FCUP - Department of Biology, Faculty of Sciences, University of Porto (U. Porto), Rua Do Campo Alegre, Porto, Portugal
| | - Filipe Alves
- MARE - Marine and Environmental Sciences Centre, Funchal, Madeira, Portugal
- ARNET - Aquatic Research Network, ARDITI, Funchal, Madeira, Portugal
| | - Isabel Sousa-Pinto
- CIMAR/CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, 4450-208, Matosinhos, S/N, Portugal
- FCUP - Department of Biology, Faculty of Sciences, University of Porto (U. Porto), Rua Do Campo Alegre, Porto, Portugal
| | - Raquel Ruivo
- CIMAR/CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, 4450-208, Matosinhos, S/N, Portugal.
| | - L Filipe C Castro
- CIMAR/CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, 4450-208, Matosinhos, S/N, Portugal.
- FCUP - Department of Biology, Faculty of Sciences, University of Porto (U. Porto), Rua Do Campo Alegre, Porto, Portugal.
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Shafer BM, West CR, Foster GE. Advancements in the neurocirculatory reflex response to hypoxia. Am J Physiol Regul Integr Comp Physiol 2024; 327:R1-R13. [PMID: 38738293 PMCID: PMC11380992 DOI: 10.1152/ajpregu.00237.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 04/16/2024] [Accepted: 04/29/2024] [Indexed: 05/14/2024]
Abstract
Hypoxia is a pivotal factor in the pathophysiology of various clinical conditions, including obstructive sleep apnea, which has a strong association with cardiovascular diseases like hypertension, posing significant health risks. Although the precise mechanisms linking hypoxemia-associated clinical conditions with hypertension remains incompletely understood, compelling evidence suggests that hypoxia induces plasticity of the neurocirculatory control system. Despite variations in experimental designs and the severity, frequency, and duration of hypoxia exposure, evidence from animal and human models consistently demonstrates the robust effects of hypoxemia in triggering reflex-mediated sympathetic activation. Both acute and chronic hypoxia alters neurocirculatory regulation and, in some circumstances, leads to sympathetic outflow and elevated blood pressures that persist beyond the hypoxic stimulus. Dysregulation of autonomic control could lead to adverse cardiovascular outcomes and increase the risk of developing hypertension.
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Affiliation(s)
- Brooke M Shafer
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Christopher R West
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, British Columbia, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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Simpson LL, Stembridge M, Siebenmann C, Moore JP, Lawley JS. Mechanisms underpinning sympathoexcitation in hypoxia. J Physiol 2024. [PMID: 38533641 DOI: 10.1113/jp284579] [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: 11/06/2023] [Accepted: 02/28/2024] [Indexed: 03/28/2024] Open
Abstract
Sympathoexcitation is a hallmark of hypoxic exposure, occurring acutely, as well as persisting in acclimatised lowland populations and with generational exposure in highland native populations of the Andean and Tibetan plateaus. The mechanisms mediating altitude sympathoexcitation are multifactorial, involving alterations in both peripheral autonomic reflexes and central neural pathways, and are dependent on the duration of exposure. Initially, hypoxia-induced sympathoexcitation appears to be an adaptive response, primarily mediated by regulatory reflex mechanisms concerned with preserving systemic and cerebral tissue O2 delivery and maintaining arterial blood pressure. However, as exposure continues, sympathoexcitation is further augmented above that observed with acute exposure, despite acclimatisation processes that restore arterial oxygen content (C a O 2 ${C_{{\mathrm{a}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ). Under these conditions, sympathoexcitation may become maladaptive, giving rise to reduced vascular reactivity and mildly elevated blood pressure. Importantly, current evidence indicates the peripheral chemoreflex does not play a significant role in the augmentation of sympathoexcitation during altitude acclimatisation, although methodological limitations may underestimate its true contribution. Instead, processes that provide no obvious survival benefit in hypoxia appear to contribute, including elevated pulmonary arterial pressure. Nocturnal periodic breathing is also a potential mechanism contributing to altitude sympathoexcitation, although experimental studies are required. Despite recent advancements within the field, several areas remain unexplored, including the mechanisms responsible for the apparent normalisation of muscle sympathetic nerve activity during intermediate hypoxic exposures, the mechanisms accounting for persistent sympathoexcitation following descent from altitude and consideration of whether there are sex-based differences in sympathetic regulation at altitude.
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Affiliation(s)
- Lydia L Simpson
- Department of Sport Science, Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | | | - Jonathan P Moore
- School of Psychology and Sport Science, Institute of Applied Human Physiology, Bangor University, Bangor, UK
| | - Justin S Lawley
- Department of Sport Science, Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
- Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy
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Dobashi K, Ichinose M, Fujii N, Fujimoto T, Nishiyasu T. Effects of Pre-Exercise Voluntary Hyperventilation on Metabolic and Cardiovascular Responses During and After Intense Exercise. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2023; 94:1141-1152. [PMID: 36170018 DOI: 10.1080/02701367.2022.2121371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 08/29/2022] [Indexed: 06/16/2023]
Abstract
Purpose: We investigated the effects of pre-exercise voluntary hyperventilation and the resultant hypocapnia on metabolic and cardiovascular responses during and after high-intensity exercise. Methods: Ten healthy participants performed a 60-s cycling exercise at a workload of 120% peak oxygen uptake in control (spontaneous breathing), hypocapnia and normocapnia trials. Hypocapnia was induced through 20-min pre-exercise voluntary hyperventilation. In the normocapnia trial, voluntary hyperpnea was performed with CO2 inhalation to prevent hypocapnia. Results: Pre-exercise end-tidal CO2 partial pressure was lower in the hypocapnia trial than the control or normocapnia trial, with similar levels in the control and normocapnia trials. Average V ˙ O 2 during the entire exercise was lower in both the hypocapnia and normocapnia trials than in the control trial (1491 ± 252vs.1662 ± 169vs.1806 ± 149 mL min-1), with the hypocapnia trial exhibiting a greater reduction than the normocapnia trial. Minute ventilation during exercise was lower in the hypocapnia trial than the normocapnia trial. In addition, minute ventilation during the first 10s of the exercise was lower in the normocapnia than the control trial. Pre-exercise hypocapnia also reduced heart rates and arterial blood pressures during the exercise relative to the normocapnia trial, a response that lasted through the subsequent early recovery periods, though end-tidal CO2 partial pressure was similar in the two trials. Conclusions: Our results suggest that pre-exercise hyperpnea and the resultant hypocapnia reduce V ˙ O 2 during high-intensity exercise. Moreover, hypocapnia may contribute to voluntary hyperventilation-mediated cardiovascular responses during the exercise, and this response can persist into the subsequent recovery period, despite the return of arterial CO2 pressure to the normocapnic level.
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Affiliation(s)
- Kohei Dobashi
- University of Tsukuba
- Japan Society for the Promotion of Science
- Hokkaido University of Education
| | | | | | - Tomomi Fujimoto
- University of Tsukuba
- Niigata University of Health and Welfare
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Tymko MM, Young D, Vergel D, Matenchuk BA, Maier LE, Sivak A, Davenport MH, Steinback CD. The effect of hypoxemia on muscle sympathetic nerve activity and cardiovascular function: a systematic review and meta-analysis. Am J Physiol Regul Integr Comp Physiol 2023; 325:R474-R489. [PMID: 37642283 DOI: 10.1152/ajpregu.00021.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 08/01/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023]
Abstract
We conducted a systematic review and meta-analysis to determine the effect of acute poikilocapnic, high-altitude, and acute isocapnia hypoxemia on muscle sympathetic nerve activity (MSNA) and cardiovascular function. A comprehensive search across electronic databases was performed until June 2021. All observational designs were included: population (healthy individuals); exposures (MSNA during hypoxemia); comparators (hypoxemia severity and duration); outcomes (MSNA; heart rate, HR; and mean arterial pressure, MAP). Sixty-one studies were included in the meta-analysis. MSNA burst frequency increased by a greater extent during high-altitude hypoxemia [P < 0.001; mean difference (MD), +22.5 bursts/min; confidence interval (CI) = -19.20 to 25.84] compared with acute poikilocapnic hypoxemia (P < 0.001; MD, +5.63 bursts/min; CI = -4.09 to 7.17) and isocapnic hypoxemia (P < 0.001; MD, +4.72 bursts/min; CI = -3.37 to 6.07). MSNA burst amplitude was only elevated during acute isocapnic hypoxemia (P = 0.03; standard MD, +0.46 au; CI = -0.03 to 0.90), and MSNA burst incidence was only elevated during high-altitude hypoxemia [P < 0.001; MD, 33.05 bursts/100 heartbeats; CI = -28.59 to 37.51]. Meta-regression analysis indicated a strong relationship between MSNA burst frequency and hypoxemia severity for acute isocapnic studies (P < 0.001) but not acute poikilocapnia (P = 0.098). HR increased by the same extent across each type of hypoxemia [P < 0.001; MD +13.81 heartbeats/min; 95% CI = 12.59-15.03]. MAP increased during high-altitude hypoxemia (P < 0.001; MD, +5.06 mmHg; CI = 3.14-6.99), and acute isocapnic hypoxemia (P < 0.001; MD, +1.91 mmHg; CI = 0.84-2.97), but not during acute poikilocapnic hypoxemia (P = 0.95). Both hypoxemia type and severity influenced sympathetic nerve and cardiovascular function. These data are important for the better understanding of healthy human adaptation to hypoxemia.
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Affiliation(s)
- Michael M Tymko
- Integrative Cerebrovascular and Environmental Physiology SB Laboratory, Department of Human Health and Nutritional Sciences, College of Biological Science, University of Guelph, Guelph, Ontario, Canada
- Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Desmond Young
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Daniel Vergel
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Brittany A Matenchuk
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sports and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Lauren E Maier
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Allison Sivak
- H.T. Coutts Education and Physical Education Library, University of Alberta, Edmonton, Alberta, Canada
| | - Margie H Davenport
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sports and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Craig D Steinback
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
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Karim S, Chahal A, Khanji MY, Petersen SE, Somers V. Autonomic Cardiovascular Control in Health and Disease. Compr Physiol 2023; 13:4493-4511. [PMID: 36994768 PMCID: PMC10406398 DOI: 10.1002/cphy.c210037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Autonomic neural control of the cardiovascular system is formed of complex and dynamic processes able to adjust rapidly to mitigate perturbations in hemodynamics and maintain homeostasis. Alterations in autonomic control feature in the development or progression of a multitude of diseases with wide-ranging physiological implications given the neural system's responsibility for controlling inotropy, chronotropy, lusitropy, and dromotropy. Imbalances in sympathetic and parasympathetic neural control are also implicated in the development of arrhythmia in several cardiovascular conditions sparking interest in autonomic modulation as a form of treatment. A number of measures of autonomic function have shown prognostic significance in health and in pathological states and have undergone varying degrees of refinement, yet adoption into clinical practice remains extremely limited. The focus of this contemporary narrative review is to summarize the anatomy, physiology, and pathophysiology of the cardiovascular autonomic nervous system and describe the merits and shortfalls of testing modalities available. © 2023 American Physiological Society. Compr Physiol 13:4493-4511, 2023.
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Affiliation(s)
- Shahid Karim
- Mayo Clinic, Rochester, Minnesota, USA
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
| | - Anwar Chahal
- Mayo Clinic, Rochester, Minnesota, USA
- University of Pennsylvania, Pennsylvania, USA
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
| | - Mohammed Y. Khanji
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
- Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
- Newham University Hospital, Barts Health NHS Trust, London, UK
| | - Steffen E. Petersen
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
- Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
- Health Data Research UK, London, UK
- Alan Turing Institute, London, UK
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Ikoma T, Naruse Y, Kaneko Y, Sakakibara T, Narumi T, Sano M, Mogi S, Suwa K, Ohtani H, Saotome M, Urushida T, Maekawa Y. Prevalence and Characteristics of Inspiration-Induced Negative Left Atrial Pressure during Pulmonary Vein Isolation. J Cardiovasc Dev Dis 2023; 10:jcdd10030101. [PMID: 36975865 PMCID: PMC10056480 DOI: 10.3390/jcdd10030101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/30/2023] [Accepted: 02/20/2023] [Indexed: 03/03/2023] Open
Abstract
Background: Atrial fibrillation (AF) ablation is performed under deep sedation, which may cause inspiration-induced negative left atrial pressure (INLAP) associated with deep inspiration. INLAP could be the cause of periprocedural complications. Methods: We retrospectively enrolled 381 patients with AF (mean age, 63.9 ± 10.8 years; 76 women; 216 cases of paroxysmal AF) who underwent CA under deep sedation using an adaptive servo ventilator (ASV). Patients whose LAP was not obtained were excluded. INLAP was defined as <0 mmHg of mean LAP during inspiration immediately after the transseptal puncture. The primary and secondary endpoints were the presence of INLAP and the incidence of periprocedural complications. Results: Among 381 patients, INLAP was observed in 133 (34.9%). Patients with INLAP had higher CHA2DS2-Vasc scores (2.3 ± 1.5 vs. 2.1 ± 1.6) and 3% oxygen desaturation indexes (median 18.6 (interquartile range 11.2–31.1) vs. 15.7 (8.1–25.3)), and higher prevalence of diabetes mellitus (23.3 vs. 13.3%) than patients without INLAP. Air embolism occurred in four patients with INLAP (3.0 vs. 0.0%). Conclusion: INLAP is not rare in patients undergoing CA for AF under deep sedation with ASV. Much attention should be paid to the possibility of air embolism in patients with INLAP.
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Haddon A, Kanhai J, Nako O, Smith TG, Hodkinson PD, Pollock RD. Cardiorespiratory Responses to Voluntary Hyperventilation During Normobaric Hypoxia. Aerosp Med Hum Perform 2023; 94:59-65. [PMID: 36755012 DOI: 10.3357/amhp.6163.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
BACKGROUND: Unexplained physiological events (PE), possibly related to hypoxia and hyperventilation, are a concern for some air forces. Physiological monitoring could aid research into PEs, with measurement of arterial oxygen saturation (Spo₂) often suggested despite potential limitations in its use. Given similar physiological responses to hypoxia and hyperventilation, the present study characterized the cardiovascular and respiratory responses to each.METHODS: Ten healthy subjects were exposed to 55 mins of normobaric hypoxia simulating altitudes of 0, 8000, and 12,000 ft (0, 2438, and 3658 m) while breathing normally and voluntarily hyperventilating (doubling minute ventilation). Respiratory gas analysis and spirometry measured end-tidal gases (PETo₂ and PETco₂) and minute ventilation. Spo₂ was assessed using finger pulse oximetry. Mean arterial, systolic, and diastolic blood pressure were measured noninvasively. Cognitive impairment was assessed using the Stroop test.RESULTS: Voluntary hyperventilation resulted in a doubling of minute ventilation and lowered PETco₂, while altitude had no effect on these. PETo₂ and Spo₂ declined with increasing altitude. However, despite a significant drop in PETo₂ of 15.2 mmHg from 8000 to 12,000 ft, Spo₂ was similar when hyperventilating (94.7 ± 2.3% vs. 93.4 ± 4.3%, respectively). The only cardiovascular response was an increase in heart rate while hyperventilating. Altitude had no effect on cognitive impairment, but hyperventilation did.DISCUSSION: For many cardiovascular and respiratory variables, there is minimal difference in responses to hypoxia and hyperventilation, making these challenging to differentiate. Spo₂ is not a reliable marker of environmental hypoxia in the presence of hyperventilation and should not be used as such without additional monitoring of minute ventilation and end-tidal gases.Haddon A, Kanhai J, Nako O, Smith TG, Hodkinson PD, Pollock RD. Cardiorespiratory responses to voluntary hyperventilation during normobaric hypoxia. Aerosp Med Hum Perform. 2023; 94(2):59-65.
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Patel M, Yarlagadda H, Upadhyay S, Neupane R, Qureshi U, Raco JD, Jain R, Jain R. Disturbed Sleep is Not Good for the Heart: A Narrative Review. Curr Cardiol Rev 2023; 19:e301122211378. [PMID: 36453501 PMCID: PMC10280991 DOI: 10.2174/1573403x19666221130100141] [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: 04/25/2022] [Revised: 10/11/2022] [Accepted: 10/31/2022] [Indexed: 12/04/2022] Open
Abstract
Sleep-related breathing disorders, including obstructive sleep apnea (OSA) and central sleep apnea (CSA), have a major impact on cardiovascular function. It has shown an association with hypertension, coronary artery disease, cardiac arrhythmias, sudden cardiac death, and congestive heart failure (CHF). This review focuses on highlighting the relationship between sleep apnea and CHF. We discuss the underlying pathophysiology, which involves the mechanical, neurohormonal, and inflammatory mechanisms; in addition, the similarities and differentiating clinical features of OSA in patients with CHF and without CHF. We have also discussed several treatment strategies, including weight loss, continuous positive airway pressure (CPAP), supplemental oxygen therapy, theophylline, acetazolamide, mandibular advancement device, and hypoglossal nerve stimulation (HGNS). We conclude that since there are several overlapping clinical features in patients with OSA with Heart Failure (HF) and without HF, early detection and treatment are crucial to decrease the risk of HF, coronary artery disease, and stroke.
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Affiliation(s)
- Meet Patel
- Department of Internal Medicine, Tianjin Medical University, Tianjin, P.R. China
| | | | | | - Ritesh Neupane
- Department of Internal Medicine, Penn State Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Umer Qureshi
- Penn State College of Medicine, Hershey, PA, USA
| | - Joseph D. Raco
- Department of Internal Medicine, Penn State Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Rahul Jain
- Avalon University School of Medicine, Willemstad, Curaçao
| | - Rohit Jain
- Avalon University School of Medicine, Willemstad, Curaçao
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Spiesshoefer J, Giannoni A, Borrelli C, Sciarrone P, Husstedt I, Emdin M, Passino C, Kahles F, Dawood T, Regmi B, Naughton M, Dreher M, Boentert M, Macefield VG. Effects of hyperventilation length on muscle sympathetic nerve activity in healthy humans simulating periodic breathing. Front Physiol 2022; 13:934372. [PMID: 36134331 PMCID: PMC9483206 DOI: 10.3389/fphys.2022.934372] [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: 05/02/2022] [Accepted: 08/10/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Periodic breathing (PB) is a cyclical breathing pattern composed of alternating periods of hyperventilation (hyperpnea, HP) and central apnea (CA). Differences in PB phenotypes mainly reside in HP length. Given that respiration modulates muscle sympathetic nerve activity (MSNA), which decreases during HP and increases during CA, the net effects of PB on MSNA may critically depend on HP length.Objectives: We hypothesized that PB with shorter periods of HP is associated with increased MSNA and decreased heart rate variability.Methods: 10 healthy participants underwent microelectrode recordings of MSNA from the common peroneal nerve along with non-invasive recording of HRV, blood pressure and respiration. Following a 10-min period of tidal breathing, participants were asked to simulate PB for 3 min following a computed respiratory waveform that emulated two PB patterns, comprising a constant CA of 20 s duration and HP of two different lengths: short (20 s) vs long (40 s). Results: Compared to (3 min of) normal breathing, simulated PB with short HP resulted in a marked increase in mean and maximum MSNA amplitude (from 3.2 ± 0.8 to 3.4 ± 0.8 µV, p = 0.04; from 3.8 ± 0.9 to 4.3 ± 1.1 µV, p = 0.04, respectively). This was paralleled by an increase in LF/HF ratio of heart rate variability (from 0.9 ± 0.5 to 2.0 ± 1.3; p = 0.04). In contrast, MSNA response to simulated PB with long HP did not change as compared to normal breathing. Single CA events consistently resulted in markedly increased MSNA (all p < 0.01) when compared to the preceding HPs, while periods of HP, regardless of duration, decreased MSNA (p < 0.05) when compared to normal breathing.Conclusion: Overall, the net effects of PB in healthy subjects over time on MSNA are dependent on the relative duration of HP: increased sympathetic outflow is seen during PB with a short but not with a long period of HP.
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Affiliation(s)
- Jens Spiesshoefer
- Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa, Italy
- Department of Pneumology and Intensive Care Medicine, University Hospital RWTH Aachen, Aachen, Germany
- *Correspondence: Jens Spiesshoefer,
| | - Alberto Giannoni
- Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | - Chiara Borrelli
- Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa, Italy
| | | | - Imke Husstedt
- Department of Neurology with Institute for Translational Neurology, University of Muenster, Muenster, Germany
| | - Michele Emdin
- Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | - Claudio Passino
- Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | - Florian Kahles
- Department of Cardiology and Vascular Medicine, University Hospital RWTH Aachen, Aachen, Germany
| | - Tye Dawood
- Human Autonomic Neurophysiology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Binaya Regmi
- Department of Pneumology and Intensive Care Medicine, University Hospital RWTH Aachen, Aachen, Germany
| | - Matthew Naughton
- Department of Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia
- Department of Medicine, Monash University, Melbourne, VIC, Australia
| | - Michael Dreher
- Department of Pneumology and Intensive Care Medicine, University Hospital RWTH Aachen, Aachen, Germany
| | - Matthias Boentert
- Fondazione Toscana Gabriele Monasterio, Pisa, Italy
- Department of Medicine, UKM Marienhospital Steinfurt, Steinfurt, Germany
| | - Vaughan G. Macefield
- Human Autonomic Neurophysiology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Anatomy & Physiology, University of Melbourne, Melbourne, VIC, Australia
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12
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Maier LE, Matenchuk BA, Vucenovic A, Sivak A, Davenport MH, Steinback CD. Influence of Obstructive Sleep Apnea Severity on Muscle Sympathetic Nerve Activity and Blood Pressure: a Systematic Review and Meta-Analysis. Hypertension 2022; 79:2091-2104. [PMID: 35766054 DOI: 10.1161/hypertensionaha.122.19288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND We conducted meta-analyses to identify relationships between obstructive sleep apnea (OSA) severity, muscle sympathetic nerve activity (MSNA), and blood pressure (BP). We quantified the effect of OSA treatment on MSNA. METHODS Structured searches of electronic databases were performed until June 2021. All observational designs (except reviews) were included: population (individuals with OSA); exposures (OSA diagnosis and direct measures of MSNA); comparator (individuals without OSA or different severity of OSA); outcomes (MSNA, BP, and heart rate). RESULTS Fifty-six studies (N=1872) were included. MSNA burst frequency was higher in OSA (27 studies; n=542) versus controls (n=488; mean differences [MDs], +15.95 bursts/min [95% CI, 12.6-17.6 bursts/min]; I2=86%). As was burst incidence (20 studies; n=357 OSA, n=312 Controls; MD, +22.23 bursts/100 hbs [95% CI, 18.49-25.97 bursts/100 hbs]; I2=67%). Meta-regressions indicated relationships between MSNA and OSA severity (burst frequency, R2=0.489; P<0.001; burst incidence, R2=0.573; P<0.001). MSNA burst frequency was related to systolic pressure (R2=0.308; P=0.016). OSA treatment with continuous positive airway pressure reduced MSNA burst frequency (MD, 11.91 bursts/min [95% CI, 9.36-14.47 bursts/min] I2=15%) and systolic (n=49; MD, 10.3 mm Hg [95% CI, 3.5-17.2 mm Hg]; I2=42%) and diastolic (MD, 6.9 mm Hg [95% CI, 2.3-11.6 mm Hg]; I2=37%) BP. CONCLUSIONS MSNA is higher in individuals with OSA and related to severity. This sympathoexcitation is also related to BP in patients with OSA. Treatment effectively reduces MSNA and BP, but limited data prevents an assessment of the link between these reductions. These data are clinically important for understanding cardiovascular disease risk in patients with OSA. REGISTRATION URL: https://www. CLINICALTRIALS gov; Unique identifier: CRD42021285159.
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Affiliation(s)
- Lauren E Maier
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation (L.E.M., A.V., C.D.S.), University of Alberta, Edmonton, Canada
| | - Brittany A Matenchuk
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation (B.A.M., M.H.D.), University of Alberta, Edmonton, Canada
| | - Ana Vucenovic
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation (L.E.M., A.V., C.D.S.), University of Alberta, Edmonton, Canada
| | - Allison Sivak
- H.T. Coutts Education and Physical Education Library (A.S.), University of Alberta, Edmonton, Canada
| | - Margie H Davenport
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation (B.A.M., M.H.D.), University of Alberta, Edmonton, Canada
| | - Craig D Steinback
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation (L.E.M., A.V., C.D.S.), University of Alberta, Edmonton, Canada
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13
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Marcoux C, Morin R, Mauger JF, Imbeault P. The Effect of Acute Intermittent and Continuous Hypoxia on Plasma Circulating ßOHB Levels Under Different Feeding Statuses in Humans. Front Physiol 2022; 13:937127. [PMID: 35874514 PMCID: PMC9298782 DOI: 10.3389/fphys.2022.937127] [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: 05/05/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction: Acute hypoxia is known to increase circulating nonesterified fatty acid (NEFA) levels. Adipose tissue lipolysis is a major source of NEFA into circulation and insulin suppresses this process when the tissue is insulin sensitive. NEFA can be esterified to triglycerides and/or completely/partially oxidized, the latter leading to ketogenesis in the liver. To our knowledge, the effect of hypoxia on ketogenesis, more specifically ß-hydroxybutyrate (ßOHB) levels, remains unknown in humans. Therefore, the objective of this study was to determine the effect of acute intermittent and continuous hypoxia on circulating ßOHB levels under different feeding status. Methods: Plasma samples from three different randomized crossover studies were assessed for ßOHB concentrations. In the first study, 14 healthy men (23 ± 3.5 years) were exposed to 6 h of normoxia or intermittent hypoxia (IH-Fed) (15 hypoxic events/hour) following an isocaloric meal. In the second study, 10 healthy men (26 ± 5.6 years) were exposed to 6 h of continuous normobaric hypoxia (CH-Fasted) (FiO2 = 0.12) or normoxia in the fasting state. In the third study (CH-Fed), 9 healthy men (24 ± 4.5 years) were exposed to 6 h of normoxia or CH in a constant prandial state. ßOHB, NEFA and insulin levels were measured during all sessions. Results: In the IH-Fed study, ßOHB and NEFA levels tended to be greater over 6 h of IH (condition × time interaction, ßOHB p = 0.108 and NEFA p = 0.062) compared to normoxia. In the CH-Fasted study, ßOHB and NEFA levels increased over time in both experimental conditions, this effect being greater under CH (condition × time interaction, ßOHB p = 0.070; NEFA p = 0.046). In the CH-Fed study, ßOHB levels slightly increased up to 180 min before falling back to initial concentrations by the end of the protocol in both normoxia and CH (main effect of time, p = 0.062), while NEFA were significantly higher under CH (p = 0.006). Conclusion: Acute normobaric hypoxia exposure tends to increase plasma ßOHB concentrations over time in healthy men. The stimulating effect of hypoxia on plasma ßOHB levels is however attenuated during postprandial and prandial states.
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Affiliation(s)
- Caroline Marcoux
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Renée Morin
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.,Institut du Savoir Montfort, Hôpital Montfort, Ottawa, ON, Canada
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14
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Clough RH, Minhas JS, Haunton VJ, Hanby MF, Robinson TG, Panerai RB. Dynamics of the cerebral autoregulatory response to paced hyperventilation assessed using sub-component and time-varying analyses. J Appl Physiol (1985) 2022; 133:311-319. [PMID: 35736950 DOI: 10.1152/japplphysiol.00100.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cerebral blood flow (CBF) can be altered by a change in partial pressure of arterial CO2 (pCO2), being reduced during hyperventilation (HPV). Critical closing pressure (CrCP) and resistance area product (RAP) are parameters which can be studied to understand this change, but their dynamic response has not been investigated during paced HPV (PHPV). Seventy five participants had recordings at rest and during PHPV. Blood pressure (BP) (Finometer), bilateral CBF velocity (CBFV) (transcranial Doppler), end-tidal CO2 (capnography) and heart rate (HR) were recorded continuously. Subcomponent analysis (SCA) and time-varying CrCP, RAP and dynamic cerebral autoregulation (Autoregulation Index, ARI) were estimated comparing PHPV to poikilocapnia. PHPV caused a change in CBFV (p<0.01), EtCO2, (p<0.01), HR (p<0.001) and RAP (p<0.01). SCA demonstrated RAP was the main parameter explaining the changes in CBFV due to PHPV. The time-varying step responses for CBFV and RAP during PHPV demonstrated considerable non-stationarity compared to poikilocapnia (p<0.00001). Although time-varying ARI was temporarily depressed, after 60 s of PHPV it was significantly higher (6.81 ± 1.88) (p<0.0001) than in poikilocapnia (5.08 ± 1.86). The mean plateau of the RAP step response was -98.3 ± 58.8 % 60 s after the onset of PHPV but -71.7 ± 45.0 % for poikilocapnia (p=0.0026), with no corresponding changes in CrCP (p=0.6). Further work is needed to assess the role of sex and aging in our findings, and the potential for using RAP and CrCP to improve the sensitivity and specificity of CO2 reactivity studies in cerebrovascular conditions.
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Affiliation(s)
- Rebecca H Clough
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Victoria J Haunton
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Martha Frances Hanby
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Thompson G Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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15
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Liang H, Yan J, Song K. Comprehensive lipidomic analysis reveals regulation of glyceride metabolism in rat visceral adipose tissue by high-altitude chronic hypoxia. PLoS One 2022; 17:e0267513. [PMID: 35522648 PMCID: PMC9075645 DOI: 10.1371/journal.pone.0267513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/10/2022] [Indexed: 11/18/2022] Open
Abstract
Adipose tissue plays a central role in energy substrate homeostasis and is a key regulator of lipid flow throughout these processes. As hypoxia affects lipid metabolism in adipose tissue, we aimed to investigate the effects of high-altitude chronic hypoxia on lipid metabolism in the adipose tissue of rats using a lipidomic analysis approach. Visceral adipose tissues from rats housed in a high-altitude hypoxia environment representing 4,300 m with 14.07% oxygen (hypoxia group) and from rats housed in a low-altitude normoxia environment representing 41 m with 20.95% oxygen (normoxia group) for 8 weeks were analyzed using an ultra-performance liquid chromatography-Orbitrap mass spectrometry system. After 8 weeks, the body weight and visceral adipose tissue weight of the hypoxia group were significantly decreased compared to those of the normoxia group (p < 0.05). The area and diameter of visceral adipose cells in the hypoxia group were significantly smaller than those of visceral adipose cells in the normoxia group (p < 0.05). The results of lipidomic analysis showed a total of 21 lipid classes and 819 lipid species. The total lipid concentration of the hypoxia group was lower than that in the normoxia group (p < 0.05). Concentrations of diacylglycerols and triacylglycerols in the hypoxia group were significantly lower than those in the normoxia group (p < 0.05). Using univariate and multivariate analyses, we identified 74 lipids that were significantly altered between the normoxia and hypoxia groups. These results demonstrate that high-altitude chronic hypoxia changes the metabolism of visceral adipose glycerides, which may potentially modulate other metabolic processes.
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Affiliation(s)
- Hong Liang
- Department of Basic Medical Sciences, Medical College, Qinghai University, Xining, PR, China
| | - Jun Yan
- Cardiovascular Medicine Department, Xuzhou Medical University affiliated Hospital, Xuzhou, PR China
| | - Kang Song
- Endocrinology Department, Qinghai Provincial People’s Hospital, Xining, PR, China
- Qinghai University affiliated Provincial People’s Hospital, Xining, PR, China
- * E-mail:
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16
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Kulas B, Klassen S, Moir ME, Shoemaker JK. Interactive effects of apneic and baroreflex stress on neural coding strategies in human muscle sympathetic nerve activity. J Neurophysiol 2022; 127:1086-1097. [PMID: 35294276 DOI: 10.1152/jn.00395.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The sympathetic nervous system exhibits patterns of action potential (AP) discharge in human muscle sympathetic nerve activity that suggest coding strategies express reflex specificity. This study explored the interactive effects of baroreceptor unloading using lower body negative pressure (LBNP) and volitional end-expiratory apnea (APN) on sympathetic postganglionic neuronal discharge patterns inferred from the firing patterns of differently sized sympathetic AP clusters. Seven individuals were studied using multi-unit microneurography (fibular) and a continuous wavelet approach to quantify AP discharge probability, recruitment, and latency during APN performed under ambient conditions, -10 and -40 mmHg LBNP. Compared to the ambient condition, LBNP increased AP discharge rate at -10 and -40 mmHg and recruited larger previously-silent sympathetic neurons at -40 mmHg. Compared to spontaneous breathing, APN increased AP discharge when performed during the ambient condition (∆351±132 AP/min), -10 mmHg (∆423±184 AP/min), and -40 mmHg (∆355±278 AP/min; main effect APN: P<0.01; LBNP-by-APN interaction: P=0.55). APN recruited larger previously-silent AP clusters during the ambient condition (∆4±3; P<0.02) and -10 mmHg (∆4±3; P<0.01), but not -40 mmHg (∆0±2; P=0.53; LBNP-by-APN: P<0.01). LBNP did not affect AP latency. However, APN reduced AP latency similarly during all conditions (ambient pressure: ∆-0.04±0.04s, -10 mmHg: ∆-0.03±0.03s, -40 mmHg: ∆-0.03±0.04s; main effect APN: P<0.01; LBNP-by-APN: P=0.48). These data indicate that apneic and baroreflex mechanisms appear to additively modify the axonal discharge rate of previously active sympathetic postganglionic neurons and interact to affect recruitment of previously-silent sympathetic neurons. Reductions in AP latency due to apneic stress were not impacted by baroreflex unloading.
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Affiliation(s)
- Bartek Kulas
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, London, Ontario, Canada
| | - Stephen Klassen
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, London, Ontario, Canada.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - M Erin Moir
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, London, Ontario, Canada
| | - J Kevin Shoemaker
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, London, Ontario, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
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17
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Hajika Y, Kawaguchi Y, Hamazaki K, Kumeda Y. Adaptive support ventilation as an effective treatment option for central sleep apnea in an older adult with heart failure with preserved ejection fraction: a case report. BMC Geriatr 2022; 22:55. [PMID: 35033005 PMCID: PMC8760753 DOI: 10.1186/s12877-021-02743-4] [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: 10/14/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
Background Adaptive support ventilation (ASV) is a proposed treatment option for central sleep apnea (CSA). Although the effectiveness of ASV remains unclear, some studies have reported promising results regarding the use of ASV in patients with heart failure with preserved ejection fraction (HfpEF). To illustrate the importance of suspecting and diagnosing sleep-disordered breathing (SDB) in older adults unable to recognize symptoms, we discuss a case in which ASV was effective in a patient with CSA and HfpEF, based on changes in the Holter electrocardiogram (ECG). Case presentation. An 82-year-old man presented to our hospital with vomiting on April 19, 2021. Approximately 10 years before admission, he was diagnosed with type 1 diabetes mellitus and recently required full support from his wife for daily activities due to cognitive dysfunction. Two days before admission, his wife was unable to administer insulin due to excessively high glucose levels, which were displayed as “high” on the patient’s glucose meter; therefore, we diagnosed the patient with diabetic ketoacidosis. After recovery, we initiated intensive insulin therapy for glycemic control. However, the patient exhibited excessive daytime sleepiness, and numerous premature ventricular contractions were observed on his ECG monitor despite the absence of hypoglycemia. As we suspected sleep-disordered breathing (SDB), we performed portable polysomnography (PSG), which revealed CSA. PSG revealed a central type of apnea and hypopnea due to an apnea–hypopnea index of 37.6, which was > 5. Moreover, the patient had daytime sleepiness; thus, we diagnosed him with CSA. We performed ASV and observed its effect using portable PSG and Holter ECG. His episodes of apnea and hypopnea were resolved, and an apparent improvement was confirmed through Holter ECG. Conclusion Medical staff should carefully monitor adult adults for signs of or risk factors for SDB to prevent serious complications. Future studies on ASV should focus on older patients with arrhythmia, as the prevalence of CSA may be underreported in this population and determine the effectiveness of ASV in patients with HfpEF, especially in older adults.
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Affiliation(s)
- Yuriko Hajika
- Department of Internal Medicine, Minami Osaka Hospital, 1-18-18 Higashikagaya, Suminoe-ku, Osaka, 559-0012, Japan.
| | - Yuji Kawaguchi
- Department of Internal Medicine, Minami Osaka Hospital, 1-18-18 Higashikagaya, Suminoe-ku, Osaka, 559-0012, Japan
| | - Kenji Hamazaki
- Department of Internal Medicine, Minami Osaka Hospital, 1-18-18 Higashikagaya, Suminoe-ku, Osaka, 559-0012, Japan
| | - Yasuro Kumeda
- Department of Internal Medicine, Minami Osaka Hospital, 1-18-18 Higashikagaya, Suminoe-ku, Osaka, 559-0012, Japan
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18
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Ma C, Xu H, Yan M, Huang J, Yan W, Lan K, Wang J, Zhang Z. Longitudinal Changes and Recovery in Heart Rate Variability of Young Healthy Subjects When Exposure to a Hypobaric Hypoxic Environment. Front Physiol 2022; 12:688921. [PMID: 35095540 PMCID: PMC8793277 DOI: 10.3389/fphys.2021.688921] [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: 03/31/2021] [Accepted: 11/23/2021] [Indexed: 11/13/2022] Open
Abstract
Background: The autonomic nervous system (ANS) is crucial for acclimatization. Investigating the responses of acute exposure to a hypoxic environment may provide some knowledge of the cardiopulmonary system’s adjustment mechanism.Objective: The present study investigates the longitudinal changes and recovery in heart rate variability (HRV) in a young healthy population when exposed to a simulated plateau environment.Methods: The study followed a strict experimental paradigm in which physiological signals were collected from 33 healthy college students (26 ± 2 years, 171 cm ± 7 cm, 64 ± 11 kg) using a medical-grade wearable device. The subjects were asked to sit in normoxic (approximately 101 kPa) and hypoxic (4,000 m above sea level, about 62 kPa) environments. The whole experimental process was divided into four stable resting measurement segments in chronological order to analyze the longitudinal changes of physical stress and recovery phases. Seventy-six time-domain, frequency-domain, and non-linear indicators characterizing rhythm variability were analyzed in the four groups.Results: Compared to normobaric normoxia, participants in hypobaric hypoxia had significantly lower HRV time-domain metrics, such as RMSSD, MeanNN, and MedianNN (p < 0.01), substantially higher frequency domain metrics such as LF/HF ratio (p < 0.05), significantly lower Poincaré plot parameters such as SD1/SD2 ratio and other Poincaré plot parameters are reduced considerably (p < 0.01), and Refined Composite Multi-Scale Entropy (RCMSE) curves are reduced significantly (p < 0.01).Conclusion: The present study shows that elevated heart rates, sympathetic activation, and reduced overall complexity were observed in healthy subjects exposed to a hypobaric and hypoxic environment. Moreover, the results indicated that Multiscale Entropy (MSE) analysis of RR interval series could characterize the degree of minor physiological changes. This novel index of HRV can better explain changes in the human ANS.
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Affiliation(s)
- Chenbin Ma
- Center for Artificial Intelligence in Medicine, Medical Innovation Research Department, PLA General Hospital, Beijing, China
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China
- School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Shenyuan Honors College, Beihang University, Beijing, China
| | - Haoran Xu
- Medical School of Chinese PLA, Beijing, China
| | - Muyang Yan
- Department of Hyperbaric Oxygen Therapy, The First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Jie Huang
- Department of Hyperbaric Oxygen Therapy, The First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Wei Yan
- Department of Hyperbaric Oxygen Therapy, The First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Ke Lan
- Beijing SensEcho Science & Technology Co., Ltd., Beijing, China
| | - Jing Wang
- School of Computer and Information Technology, Beijing Jiaotong University, Beijing, China
- *Correspondence: Jing Wang,
| | - Zhengbo Zhang
- Center for Artificial Intelligence in Medicine, Medical Innovation Research Department, PLA General Hospital, Beijing, China
- Zhengbo Zhang,
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19
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Čarná Z, Osmančík P. The Effect of Obesity, Hypertension, Diabetes Mellitus, Alcohol, and Sleep Apnea on the Risk of Atrial Fibrillation. Physiol Res 2021. [DOI: 10.33549//physiolres.934744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia associated with a two-fold increase in mortality caused by a higher risk of stroke and heart failure. Currently, AF is present in ~ 2 % of the general population, and its incidence and prevalence are increasing. Obesity, hypertension, diabetes mellitus, obstructive sleep apnea, and alcohol consumption increase the risk of AF. Each unit of increase in BMI increases the risk of AF by 3 %, and intensive weight loss is also associated with reduced AF recurrence. Hypertension increases the risk of AF by 50 % in men and by 40 % in women, and explains ≈ 20 % of new AF cases. Patients with obstructive sleep apnea are at four times higher risk of developing AF than subjects without sleep apnea. Higher concentrations of pro-inflammatory cytokines, higher amounts of epicardial adipose tissue, and a higher degree of ventricular diffuse myocardial fibrosis are present in AF patients and patients with the aforementioned metabolic disorders. Several prospective cohort studies and randomized trials have been initiated to show whether weight loss and treatment of other risk factors will be associated with a reduction in AF recurrences.
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Affiliation(s)
| | - P Osmančík
- Cardiocenter, Charles University Prague, Dept. Of Cardiology, Prague, Czech Republic.
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20
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Steele AR, Skow RJ, Fraser GM, Berthelsen LF, Steinback CD. Sympathetic neurovascular transduction following acute hypoxia. Clin Auton Res 2021; 31:755-765. [PMID: 34528146 DOI: 10.1007/s10286-021-00824-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/18/2021] [Indexed: 01/29/2023]
Abstract
PURPOSE Following an acute exposure to hypoxia, sympathetic nerve activity remains elevated. However, this elevated sympathetic nerve activity does not elicit a parallel increase in vascular resistance suggesting a blunted sympathetic signaling [i.e. blunted sympathetic neurovascular transduction (sNVT)]. Therefore, we sought to quantify spontaneous sympathetic bursts and related changes in total peripheral resistance following hypoxic exposure. We hypothesized that following hypoxia sNVT would be blunted. METHODS Nine healthy participants (n = 6 men; mean age 25 ± 2 years) were recruited. We collected data on muscle sympathetic nerve activity (MSNA) using microneurography and beat-by-beat total peripheral resistance (TPR) via finger photoplethysmography at baseline, during acute hypoxia and during two periods of recovery (recovery period 1, 0-10 min post hypoxia; recovery period 2, 10-20 min post hypoxia). MSNA burst sequences (i.e. singlets, doublets, triplets and quads+) were identified and coupled to changes in TPR over 15 cardiac cycles as an index of sNVT for burst sequences. A sNVT slope for each participant was calculated from the slope of the relationship between TPR plotted against normalized burst amplitude. RESULTS The sNVT slope was blunted during hypoxia [Δ 0.0044 ± 0.0014 (mmHg/L/min)/(a.u.)], but unchanged following termination of hypoxia [recovery 1, Δ 0.031 ± 0.0019 (mmHg/L/min)/(a.u.); recovery 2, Δ 0.0038 ± 0.0014 (mmHg/L/min)/(a.u.) compared to baseline (Δ 0.038 ± 0.0015 (L/min/mmHg)/(a.u.)] (main effect of group p = 0.012). CONCLUSIONS Contrary to our hypothesis, we have demonstrated that systemic sNVT is unchanged following hypoxia in young healthy adults.
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Affiliation(s)
- Andrew R Steele
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, , University of Alberta, 1-059D Li Ka Shing Centre for Health Research Innovation, Edmonton, AB, Canada, T6G 2E1
| | - Rachel J Skow
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, , University of Alberta, 1-059D Li Ka Shing Centre for Health Research Innovation, Edmonton, AB, Canada, T6G 2E1
- Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Graham M Fraser
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Lindsey F Berthelsen
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, , University of Alberta, 1-059D Li Ka Shing Centre for Health Research Innovation, Edmonton, AB, Canada, T6G 2E1
| | - Craig D Steinback
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, , University of Alberta, 1-059D Li Ka Shing Centre for Health Research Innovation, Edmonton, AB, Canada, T6G 2E1.
- Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada.
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
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21
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Morin R, Goulet N, Mauger JF, Imbeault P. Physiological Responses to Hypoxia on Triglyceride Levels. Front Physiol 2021; 12:730935. [PMID: 34497541 PMCID: PMC8419320 DOI: 10.3389/fphys.2021.730935] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/03/2021] [Indexed: 11/25/2022] Open
Abstract
Hypoxia is a condition during which the body or specific tissues are deprived of oxygen. This phenomenon can occur in response to exposure to hypoxic environmental conditions such as high-altitude, or because of pathophysiological conditions such as obstructive sleep apnea. Circumstances such as these can restrict supply or increase consumption of oxygen, leading to oxyhemoglobin desaturation and tissue hypoxia. In certain cases, hypoxia may lead to severe health consequences such as an increased risk of developing cardiovascular diseases and type 2 diabetes. A potential explanation for the link between hypoxia and an increased risk of developing cardiovascular diseases lies in the disturbing effect of hypoxia on circulating blood lipids, specifically its capacity to increase plasma triglyceride concentrations. Increased circulating triglyceride levels result from the production of triglyceride-rich lipoproteins, such as very-low-density lipoproteins and chylomicrons, exceeding their clearance rate. Considerable research in murine models reports that hypoxia may have detrimental effects on several aspects of triglyceride metabolism. However, in humans, the mechanisms underlying the disturbing effect of hypoxia on triglyceride levels remain unclear. In this mini-review, we outline the available evidence on the physiological responses to hypoxia and their impact on circulating triglyceride levels. We also discuss mechanisms by which hypoxia affects various organs involved in the metabolism of triglyceride-rich lipoproteins. This information will benefit scientists and clinicians interested in the mechanistic of the regulatory cascade responsible for the response to hypoxia and how this response could lead to a deteriorated lipid profile and an increased risk of developing hypoxia-related health consequences.
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Affiliation(s)
- Renée Morin
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Nicholas Goulet
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.,Hôpital Montfort, Institut du Savoir Montfort, Ottawa, ON, Canada
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22
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Voulgaris A, Archontogeorgis K, Steiropoulos P, Papanas N. Cardiovascular Disease in Patients with Chronic Obstructive Pulmonary Disease, Obstructive Sleep Apnoea Syndrome and Overlap Syndrome. Curr Vasc Pharmacol 2021; 19:285-300. [PMID: 32188387 DOI: 10.2174/1570161118666200318103553] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 12/12/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea syndrome (OSAS) are among the most prevalent chronic respiratory disorders. Accumulating data suggest that there is a significant burden of cardiovascular disease (CVD) in patients with COPD and OSAS, affecting negatively patients' quality of life and survival. Overlap syndrome (OS), i.e. the co-existence of both COPD and OSAS in the same patient, has an additional impact on the cardiovascular system multiplying the risk of morbidity and mortality. The underlying mechanisms for the development of CVD in patients with either OSAS or COPD and OS are not entirely elucidated. Several mechanisms, in addition to smoking and obesity, may be implicated, including systemic inflammation, increased sympathetic activity, oxidative stress and endothelial dysfunction. Early diagnosis and proper management of these patients might reduce cardiovascular risk and improve patients' survival. In this review, we summarize the current knowledge regarding epidemiological aspects, pathophysiological mechanisms and present point-to-point specific associations between COPD, OSAS, OS and components of CVD, namely, pulmonary hypertension, coronary artery disease, peripheral arterial disease and stroke.
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Affiliation(s)
- A Voulgaris
- MSc Programme in Sleep Medicine, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - K Archontogeorgis
- MSc Programme in Sleep Medicine, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - P Steiropoulos
- MSc Programme in Sleep Medicine, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - N Papanas
- Diabetes Centre, Second Department of Internal Medicine, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
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23
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Byun JI, Cha KS, Jun JE, Kim TJ, Jung KY, Jeong IK, Shin WC. Dynamic changes in nocturnal blood glucose levels are associated with sleep-related features in patients with obstructive sleep apnea. Sci Rep 2020; 10:17877. [PMID: 33087786 PMCID: PMC7578637 DOI: 10.1038/s41598-020-74908-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022] Open
Abstract
Obstructive sleep apnea (OSA) has a bidirectional relationship with insulin resistance conditions; however, the mechanism remains unclear. This study aimed to compare dynamic nocturnal glucose changes among patients with OSA of varying levels of severity and evaluate temporal changes associated with the cardinal features of OSA (sympathetic hyperactivation, intermittent hypoxemia, and sleep fragmentation) in nondiabetic subjects. Nocturnal glucose was measured with a continuous glucose monitoring device every 5 min during polysomnography (PSG). The OSA features were evaluated using heart rate variability (HRV), minimum saturation, and electroencephalography. Eleven subjects with moderate to severe OSA and 12 subjects with no or mild OSA were evaluated. Those with moderate to severe OSA showed an increasing trend in blood glucose levels after sleep onset, whereas those without or with mild OSA showed a decreasing trend (F = 8.933, p < 0.001). Delta band power also showed different trends during sleep between the two groups (F = 2.991, p = 0.009), and minimum saturation remained lower in the moderate to severe OSA group than in the no or mild OSA group. High degrees of coupling between nocturnal glucose levels and each OSA feature were observed. Altered trends in nocturnal glucose in moderate to severe OSA may reflect glucose intolerance and result in metabolic consequences. Managing the features of sleep-related OSA may have implications for metabolic management in the future.
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Affiliation(s)
- Jung-Ick Byun
- Department of Neurology, Kyung Hee University School of Medicine, Kyung Hee University Hospital At Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, 134-727, Republic of South Korea
| | - Kwang Su Cha
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of South Korea
| | - Ji Eun Jun
- Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Kyung Hee University Hospital At Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, 134-727, Republic of South Korea
| | - Tae-Joon Kim
- Department of Neurology, Ajou University School of Medicine, Suwon, Republic of South Korea
| | - Ki-Young Jung
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of South Korea
| | - In-Kyung Jeong
- Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Kyung Hee University Hospital At Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, 134-727, Republic of South Korea.
| | - Won Chul Shin
- Department of Neurology, Kyung Hee University School of Medicine, Kyung Hee University Hospital At Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, 134-727, Republic of South Korea.
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24
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Hess HW, Hostler D, Clemency BM, Johnson BD. Carotid body chemosensitivity at 1.6 ATA breathing air versus 100% oxygen. J Appl Physiol (1985) 2020; 129:247-256. [PMID: 32584669 DOI: 10.1152/japplphysiol.00275.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hyperoxia reduces the ventilatory response to hypercapnia by suppressing carotid body (CB) activation. This effect may contribute to CO2 retention during underwater diving due to the high arterial O2 content associated with hyperbaria. We tested the hypothesis that CB chemosensitivity to hypercapnia and hypoxia is attenuated during hyperbaria. Ten subjects completed two, 4-h dry dives at 1.6 atmosphere absolute (ATA) breathing either 21% O2 (Air) or 100% O2 (100% O2). CB chemosensitivity was assessed using brief hypercapnic ventilatory response ([Formula: see text]) and hypoxic ventilatory response ([Formula: see text]) tests predive, 75 and 155 min into the dives, and 15 and 55 min postdive. End-tidal CO2 pressure increased during the dive at 75 and 155 min [Air: +9 (SD 4) mmHg and +8 (SD 4) mmHg versus 100% O2: +6 (SD 4) mmHg and +5 (SD 3) mmHg; all P < 0.01] and was higher while breathing Air (P < 0.01). [Formula: see text] was unchanged during the dive (P = 0.73) and was not different between conditions (P = 0.47). However, [Formula: see text] was attenuated from predive during the dive at 155 min breathing Air [-0.035 (SD 0.037) L·min·mmHg-1; P = 0.02] and at both time points while breathing 100% O2 [-0.035 (SD 0.052) L·min·mmHg-1 and -0.034 (SD 0.064) L·min·mmHg-1; P = 0.02 and P = 0.02, respectively]. These data indicate that the CB chemoreceptors do not appear to contribute to CO2 retention in hyperbaria.NEW & NOTEWORTHY We demonstrate that carotid body chemosensitivity to brief exposures of hypercapnia was unchanged during a 4-h dive in a dry hyperbaric chamber at 1.6 ATA regardless of breathing gas condition [i.e., air (21% O2) versus 100% oxygen]. Therefore, it appears that an attenuation of carotid body chemosensitivity to hypercapnia does not contribute to CO2 retention in hyperbaria.
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Affiliation(s)
- Hayden W Hess
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - David Hostler
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Brian M Clemency
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York.,Department of Emergency Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - Blair D Johnson
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
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25
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Simpson LL, Meah VL, Steele A, Thapamagar S, Gasho C, Anholm JD, Drane AL, Dawkins TG, Busch SA, Oliver SJ, Lawley JS, Tymko MM, Ainslie PN, Steinback CD, Stembridge M, Moore JP. Evidence for a physiological role of pulmonary arterial baroreceptors in sympathetic neural activation in healthy humans. J Physiol 2020; 598:955-965. [PMID: 31977069 DOI: 10.1113/jp278731] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/20/2020] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS In an anaesthetised animal model, independent stimulation of baroreceptors in the pulmonary artery elicits reflex sympathoexcitation. In humans, pulmonary arterial pressure is positively related to basal muscle sympathetic nerve activity (MSNA) under conditions where elevated pulmonary pressure is evident (e.g. high altitude); however, a causal link is not established. Using a novel experimental approach, we demonstrate that reducing pulmonary arterial pressure lowers basal MSNA in healthy humans. This response is distinct from the negative feedback reflex mediated by aortic and carotid sinus baroreceptors when systemic arterial pressure is lowered. Afferent input from pulmonary arterial baroreceptors may contribute to sympathetic neural activation in healthy lowland natives exposed to high altitude. ABSTRACT In animal models, distension of baroreceptors located in the pulmonary artery induces a reflex increase in sympathetic outflow; however, this has not been examined in humans. Therefore, we investigated whether reductions in pulmonary arterial pressure influenced sympathetic outflow and baroreflex control of muscle sympathetic nerve activity (MSNA). Healthy lowlanders (n = 13; 5 females) were studied 4-8 days following arrival at high altitude (4383 m; Cerro de Pasco, Peru), a setting that increases both pulmonary arterial pressure and sympathetic outflow. MSNA (microneurography) and blood pressure (BP; photoplethysmography) were measured continuously during ambient air breathing (Amb) and a 6 min inhalation of the vasodilator nitric oxide (iNO; 40 ppm in 21% O2 ), to selectively lower pulmonary arterial pressure. A modified Oxford test was performed under both conditions. Pulmonary artery systolic pressure (PASP) was determined using Doppler echocardiography. iNO reduced PASP (24 ± 3 vs. 32 ± 5 mmHg; P < 0.001) compared to Amb, with a similar reduction in MSNA total activity (1369 ± 576 to 994 ± 474 a.u min-1 ; P = 0.01). iNO also reduced the MSNA operating point (burst incidence; 39 ± 16 to 33 ± 17 bursts·100 Hb-1 ; P = 0.01) and diastolic operating pressure (82 ± 8 to 80 ± 8 mmHg; P < 0.001) compared to Amb, without changing heart rate (P = 0.6) or vascular-sympathetic baroreflex gain (P = 0.85). In conclusion, unloading of pulmonary arterial baroreceptors reduced basal sympathetic outflow to the skeletal muscle vasculature and reset vascular-sympathetic baroreflex control of MSNA downward and leftward in healthy humans at high altitude. These data suggest the existence of a lesser-known reflex input involved in sympathetic activation in humans.
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Affiliation(s)
- Lydia L Simpson
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Wales, UK
| | - Victoria L Meah
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada
| | - Andrew Steele
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada
| | - Suman Thapamagar
- Division of Pulmonary and Critical Care, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Christopher Gasho
- Division of Pulmonary and Critical Care, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - James D Anholm
- Division of Pulmonary and Critical Care, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Aimee L Drane
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Wales, UK
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Wales, UK
| | - Stephen A Busch
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada
| | - Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Wales, UK
| | - Justin S Lawley
- Department of Sport Science, Division of Physiology, University of Innsbruck, Austria
| | - Michael M Tymko
- Centre for Heart, Lung, and Vascular Health, University of British Columbia Okanagan, Kelowna, Canada
| | - Phillip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia Okanagan, Kelowna, Canada
| | - Craig D Steinback
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Wales, UK
| | - Jonathan P Moore
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Wales, UK
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26
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Roder F, Wellmann B, Bitter T, Fox H, Türoff A, Spiesshoefer J, Tamisier R, Horstkotte D, Oldenburg O. Sleep duration and architecture during ASV for central sleep apnoea in systolic heart failure. Respir Physiol Neurobiol 2020; 271:103286. [DOI: 10.1016/j.resp.2019.103286] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 08/28/2019] [Accepted: 08/29/2019] [Indexed: 01/19/2023]
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27
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Ott EP, Baker SE, Holbein WW, Shoemaker JK, Limberg JK. Effect of varying chemoreflex stress on sympathetic neural recruitment strategies during apnea. J Neurophysiol 2019; 122:1386-1396. [PMID: 31389742 DOI: 10.1152/jn.00319.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We sought to examine the effect of varying chemoreflex stress on sympathetic neural recruitment strategies during end-expiratory apnea. We hypothesized that increases in the firing frequency and probability of low-threshold axons at the asphyxic "break point" would be exaggerated during hypoxia and attenuated during hyperoxia. Multiunit muscle sympathetic nervous system activity (MSNA) (peroneal nerve microneurography) was measured in 10 healthy male subjects (31 ± 2 yr, 25 ± 1 kg/m2). Individuals completed maximal voluntary end-expiratory apnea under normoxic, hypoxic (inspired O2 fraction: 0.17 ± 0.01), and hyperoxic (inspired O2 fraction: 0.92 ± 0.03) conditions. Action potential (AP) patterns were examined from the filtered raw signal with wavelet-based methodology. Multiunit MSNA was increased (P ≤ 0.05) during normoxic apnea, because of an increase in the frequency and incidence of AP spikes (243 ± 75 to 519 ± 134 APs/min, P = 0.048; 412 ± 133 to 733 ± 185 APs/100 heartbeats, P = 0.02). Multiunit MSNA increased from baseline (P < 0.01) during hypoxic apnea, which was due to an increase in the frequency and incidence of APs (192 ± 59 to 952 ± 266 APs/min, P < 0.01; 326 ± 89 to 1,212 ± 327 APs/100 heartbeats, P < 0.01). Hypoxic apnea also resulted in an increase in the probability of a particular AP cluster firing more than once per burst (P < 0.01). Hyperoxia attenuated any increase in MSNA with apnea, such that no changes in multiunit MSNA or frequency or incidence of AP spikes were observed (P > 0.05). We conclude that increases in frequency and incidence of APs during apnea are potentiated during hypoxia and suppressed when individuals are hyperoxic, highlighting the important impact of chemoreflex stress in AP discharge patterns. The results may have implications for neural control of the circulation in recreational activities and/or clinical conditions prone to apnea.NEW & NOTEWORTHY Our results demonstrate that, compared with normoxic end-expiratory apnea, hypoxic apnea increases the frequency and incidence of action potential spikes as well as the probability of multiple firing. We further show that this response is suppressed when individuals are hyperoxic. These data highlight the potentially important role of chemoreflex stress in neural firing and recruitment and may have implications for neural control of the circulation in recreational and/or clinical conditions prone to apnea.
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Affiliation(s)
- Elizabeth P Ott
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Sarah E Baker
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Walter W Holbein
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - J Kevin Shoemaker
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada
| | - Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
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28
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Reshetnik A, Puppe S, Bonnemeier H. Central Sleep Apnoea and Arrhythmogenesis After Myocardial Infarction-The CESAAR Study. Front Cardiovasc Med 2019; 6:108. [PMID: 31448290 PMCID: PMC6691753 DOI: 10.3389/fcvm.2019.00108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/19/2019] [Indexed: 12/26/2022] Open
Abstract
The prevalence of sleep disordered breathing (SDB) after acute myocardial infarction (AMI) is high. However, little is known about predominant SDB type and the impact of SDB severity on arrhythmogenesis. We conducted a prospective single-center observational study and performed an unattended sleep study and Holter monitoring within 10 days after AMI, and an unattended sleep study 11.3 months after AMI. All patients were included from the Department of Cardiology at the University Hospital Schleswig-Holstein, Lübeck, Germany. A total of 202 subjects with AMI (73.8% with ST-elevation; 59.8 years; 73.8% male) were included. The mean BMI was 27.8 kg/m2 and the mean neck/waist circumference was 41.7/103.3 cm. The mean left ventricular ejection fraction was 56.6%. The SDB prevalence defined as apnoea-hypopnea-index (AHI) ≥ 5/h was 66.7% with 44.9% having central (CSA), and 21.8% obstructive sleep apnoea (OSA). The mean AHI was 13.8 1/h. In 10.2% nsVT was detected in the Holter monitoring. AI >23/h was independently associated with higher risk of nsVT in the subacute AMI period. SDB is highly prevalent and CSA a predominant type of SDB in the subacute phase after uncomplicated AMI treated with modern revascularization procedures and evidence-based pharmacological therapy. Severe SDB is independently associated with higher risk for nsVT in the subacute AMI period and its course should be monitored as it can potentially have a negative impact on relevant outcomes of AMI patients. Further prospective studies are needed to assess long-term follow up of SDB after AMI and its impact on mortality and morbidity.
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Affiliation(s)
- Alexander Reshetnik
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Nephrology, Berlin, Germany
| | - Swetlana Puppe
- Department of Psychiatry, Evangelisches Krankenhaus Königin Elisabeth Herzberge gGmbH, Berlin, Germany
| | - Hendrik Bonnemeier
- Department of Cardiology, Universitätsklinik Schleswig-Holstein, Kiel, Germany
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29
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Katayama K, Saito M. Muscle sympathetic nerve activity during exercise. J Physiol Sci 2019; 69:589-598. [PMID: 31054082 PMCID: PMC10717921 DOI: 10.1007/s12576-019-00669-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 02/22/2019] [Indexed: 11/25/2022]
Abstract
Appropriate cardiovascular adjustment is necessary to meet the metabolic demands of working skeletal muscle during exercise. The sympathetic nervous system plays a crucial role in the regulation of arterial blood pressure and blood flow during exercise, and several important neural mechanisms are responsible for changes in sympathetic vasomotor outflow. Changes in sympathetic vasomotor outflow (i.e., muscle sympathetic nerve activity: MSNA) in inactive muscles during exercise differ depending on the exercise mode (static or dynamic), intensity, duration, and various environmental conditions (e.g., hot and cold environments or hypoxic). In 1991, Seals and Victor [6] reviewed MSNA responses to static and dynamic exercise with small muscle mass. This review provides an updated comprehensive overview on the MSNA response to exercise including large-muscle, dynamic leg exercise, e.g., two-legged cycling, and its regulatory mechanisms in healthy humans.
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Affiliation(s)
- Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, 464-8601, Japan.
- Graduate School of Medicine, Nagoya University, Nagoya, Japan.
| | - Mitsuru Saito
- Applied Physiology Laboratory, Toyota Technological Institute, Nagoya, Japan
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30
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Keir DA, Duffin J, Millar PJ, Floras JS. Simultaneous assessment of central and peripheral chemoreflex regulation of muscle sympathetic nerve activity and ventilation in healthy young men. J Physiol 2019; 597:3281-3296. [DOI: 10.1113/jp277691] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/13/2019] [Indexed: 12/20/2022] Open
Affiliation(s)
- Daniel A. Keir
- University Health Network and Mount Sinai Hospital Division of CardiologyDepartment of Medicine, University of Toronto Toronto Ontario Canada
| | - James Duffin
- Departments of Anaesthesia and PhysiologyUniversity of Toronto Toronto Ontario Canada
- Thornhill Research Inc. Toronto Ontario Canada
| | - Philip J. Millar
- University Health Network and Mount Sinai Hospital Division of CardiologyDepartment of Medicine, University of Toronto Toronto Ontario Canada
- Human Health and Nutritional ScienceUniversity of Guelph Guelph Ontario Canada
| | - John S. Floras
- University Health Network and Mount Sinai Hospital Division of CardiologyDepartment of Medicine, University of Toronto Toronto Ontario Canada
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31
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Agaltsov MV, Drapkina OM, Davtyan KV, Arutyunyan GG. The prevalence of sleep breathing disorders in patients with atrial fibrillation undergoing catheter treatment. RATIONAL PHARMACOTHERAPY IN CARDIOLOGY 2019. [DOI: 10.20996/1819-6446-2019-15-1-36-42] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aim. To study the prevalence of obstructive sleep apnea (OSA) among patients with atrial fibrillation (AF) who have undergone catheter treatment for this arrhythmia, as well as to study the possible interrelationships of these sleep breathing disorders with comorbid diseases and the received therapy in this cohort.Material and methods. 231 patients from a random sample were examined (men – 118 [51.1%], mean age 57.8±9.3 years) in the range of 1-6 months after catheter therapy for AF. All patients underwent cardiorespiratory sleep monitoring for one night. The criterion for OSA severity was apnea/hypopnea index (AHI) for hour (the norm is less than 5 events/h). Depending on the results obtained, all patients were divided into groups without apnea and with apnea of varying severity – a mild degree with an AHI value of 5 to 15 events/h, moderate severity with an AHI value of 16 to 30 events/h, and severe degree when the value of AHI more than 30 events/h. The study was performed without abolishing the basic therapy.Results. According to the results of cardiorespiratory sleep monitoring 127 patients (56.7%) with OSA criteria, were registered. Among them, a mild degree of OSA was found in 35.4% (n=45), a moderate degree – in 40.9% (n=52), and severe one – in 23.7% (n=30) of all patients with apnea. Among patients with obstructive sleep apnea 51.1% were males. Arterial hypertension was significantly more frequent in patients with OSA of pronounced degrees of severity compared with patients without apnea (p=0.047). Weight and body mass index of patients with OSA were significantly higher than in patients without apnea (p=0.001 and p=0.001, respectively). The left atrium (LA) size in patients with severe OSA was significantly larger than in patients without apnea (p=0.0005), which may indicate a possible contribution of severe obstructive apnea to the arrhythmia generating. OSA was the strongest independent factor among others related to the LA size (odds ratio was 1.6; 95% confidence interval 1.2-2.1; p<0.0003).Conclusion. Obstructive sleep apnea is very widespread among a cohort of patients with AF who have undergone a catheter procedure to isolate the pulmonary veins. Sleep breathing disorder is the strongest and most independent risk factor for AF associated with increased LA, among other risk factors such as age, hypertension, and obesity.
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Affiliation(s)
- M. V. Agaltsov
- National Medical Research Center for Preventive Medicine
| | - O. M. Drapkina
- National Medical Research Center for Preventive Medicine
| | - K. V. Davtyan
- National Medical Research Center for Preventive Medicine
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32
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Palma JA, Gileles-Hillel A, Norcliffe-Kaufmann L, Kaufmann H. Chemoreflex failure and sleep-disordered breathing in familial dysautonomia: Implications for sudden death during sleep. Auton Neurosci 2019; 218:10-15. [PMID: 30890343 DOI: 10.1016/j.autneu.2019.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/11/2019] [Indexed: 01/04/2023]
Abstract
Familial dysautonomia (Riley-Day syndrome, hereditary sensory and autonomic neuropathy type III) is a rare autosomal recessive disease characterized by impaired development of primary sensory and autonomic neurons resulting in a severe neurological phenotype, which includes arterial baroreflex and chemoreflex failure with high frequency of sleep-disordered breathing and sudden death during sleep. Although a rare disease, familial dysautonomia represents a unique template to study the interactions between sleep-disordered breathing and abnormal chemo- and baroreflex function. In patients with familial dysautonomia, ventilatory responses to hypercapnia are reduced, and to hypoxia are almost absent. In response to hypoxia, these patients develop paradoxical hypoventilation, hypotension, bradycardia, and potentially, death. Impaired ventilatory control due to chemoreflex failure acquires special relevance during sleep when conscious control of respiration withdraws. Overall, almost all adult (85%) and pediatric (95%) patients have some degree of sleep-disordered breathing. Obstructive apnea events are more frequent in adults, whereas central apnea events are more severe and frequent in children. The annual incidence rate of sudden death during sleep in patients with familial dysautonomia is 3.4 per 1000 person-year, compared to 0.5-1 per 1000 person-year of sudden unexpected death in epilepsy. This review summarizes recent developments in the understanding of sleep-disordered breathing in patients with familial dysautonomia, the risk factors for sudden death during sleep, and the specific interventions that could prevent it.
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Affiliation(s)
- Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States of America
| | - Alex Gileles-Hillel
- Departments of Pediatrics, Pediatric Pulmonology and Sleep, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States of America
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States of America.
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Busch SA, Bruce CD, Skow RJ, Pfoh JR, Day TA, Davenport MH, Steinback CD. Mechanisms of sympathetic regulation during Apnea. Physiol Rep 2019; 7:e13991. [PMID: 30693670 PMCID: PMC6349657 DOI: 10.14814/phy2.13991] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 12/26/2018] [Indexed: 12/11/2022] Open
Abstract
Volitional Apnea produces a robust peak sympathetic response through several interacting mechanisms. However, the specific contribution of each mechanism has not been elucidated. Muscle sympathetic activity was collected in participants (n = 10; 24 ± 3 years) that performed four maximal volitional apneas aimed at isolating lung-stretch (mechanical) and chemoreflex drive: (Ainslie and Duffin ) end-expiratory breath-hold, (Ainslie et al. ) end-inspiratory breath-hold, (Alpher et al. ) prehyperventilation breath-hold, and (Andersson and Schagatay ) prehyperoxia breath-hold. A final repeated rebreathe breath-hold protocol was performed to measure the peak sympathetic response during successive breath-holds at increasing chemoreflex stress. Finally, the influence of dynamic ventilation was assessed through asphyxic rebreathe. Muscle sympathetic activity was calculated as the change in burst frequency (burst/min), burst incidence (burst/100 heart-beats), and amplitude (au) between baseline and prevolitional breakpoint. Rebreathe was analyzed at similar chemoreflex stress as inspiratory breath-hold. All maneuvers increased muscle sympathetic activity compared to baseline (P < 0.01). However, prehyperoxia exhibited a smaller increase (+22.18 ± 9.13 burst/min; +25.52 ± 11.7 burst/100 heart-beats) compared to inspiratory, expiratory, and prehyperventilation breath-holds. At similar chemoreflex strain, rebreathe sympathetic activity was blunted compared to inspiratory breath-hold (P < 0.01). Finally, muscle sympathetic activity was not different between the repeated rebreathe trials, despite elevated chemoreflex stress and lower breath-hold duration with each subsequent breath-hold. We have demonstrated an obligatory role of the peripheral, but not central, chemoreflex (prehyperventilation vs. prehyperoxia) in producing peak sympathetic responses. At similar chemoreflex stresses the act of dynamic ventilation, but not static lung stretch per se, blunts muscle sympathetic activity. Finally, similar peak sympathetic responses during successive repeated breath-holds suggest a sympathetic ceiling may exist.
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Affiliation(s)
- Stephen A. Busch
- Neurovascular Health LaboratoryFaculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonAlbertaCanada
| | - Christina D. Bruce
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Rachel J. Skow
- Neurovascular Health LaboratoryFaculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonAlbertaCanada
| | - Jaime R. Pfoh
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Trevor A. Day
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Margie H. Davenport
- Neurovascular Health LaboratoryFaculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonAlbertaCanada
| | - Craig D. Steinback
- Neurovascular Health LaboratoryFaculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonAlbertaCanada
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Siebenmann C, Ryrsø CK, Oberholzer L, Fisher JP, Hilsted LM, Rasmussen P, Secher NH, Lundby C. Hypoxia-induced vagal withdrawal is independent of the hypoxic ventilatory response in men. J Appl Physiol (1985) 2019; 126:124-131. [DOI: 10.1152/japplphysiol.00701.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypoxia increases heart rate (HR) in humans by sympathetic activation and vagal withdrawal. However, in anaesthetized dogs hypoxia increases vagal activity and reduces HR if pulmonary ventilation does not increase and we evaluated whether that observation applies to awake humans. Ten healthy males were exposed to 15 min of normoxia and hypoxia (10.5% O2), while respiratory rate and tidal volume were volitionally controlled at values identified during spontaneous breathing in hypoxia. End-tidal CO2 tension was clamped at 40 mmHg by CO2 supplementation. β-Adrenergic blockade by intravenous propranolol isolated vagal regulation of HR. During spontaneous breathing, hypoxia increased ventilation by 3.2 ± 2.1 l/min ( P = 0.0033) and HR by 8.9 ± 5.5 beats/min ( P < 0.001). During controlled breathing, respiratory rate (16.3 ± 3.2 vs. 16.4 ± 3.3 breaths/min) and tidal volume (1.05 ± 0.27 vs. 1.06 ± 0.24 l) were similar for normoxia and hypoxia, whereas the HR increase in hypoxia persisted without (8.6 ± 10.2 beats/min) and with (6.6 ± 5.6 beats/min) propranolol. Neither controlled breathing ( P = 0.80), propranolol ( P = 0.64), nor their combination ( P = 0.89) affected the HR increase in hypoxia. Arterial pressure was unaffected ( P = 0.48) by hypoxia across conditions. The hypoxia-induced increase in HR during controlled breathing and β-adrenergic blockade indicates that hypoxia reduces vagal activity in humans even when ventilation does not increase. Vagal withdrawal in hypoxia seems to be governed by the arterial chemoreflex rather than a pulmonary inflation reflex in humans. NEW & NOTEWORTHY Hypoxia accelerates the heart rate of humans by increasing sympathetic activity and reducing vagal activity. Animal studies have indicated that hypoxia-induced vagal withdrawal is governed by a pulmonary inflation reflex that is activated by the increased pulmonary ventilation in hypoxia. The present findings, however, indicate that humans experience vagal withdrawal in hypoxia even if ventilation does not increase, indicating that vagal withdrawal is governed by the arterial chemoreflex rather than a pulmonary inflation reflex.
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Affiliation(s)
- Christoph Siebenmann
- The Centre for Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Camilla K. Ryrsø
- The Centre for Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Laura Oberholzer
- The Centre for Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - James P. Fisher
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, United Kingdom
| | - Linda M. Hilsted
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | | | - Niels H. Secher
- Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Carsten Lundby
- The Centre for Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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35
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Impact of Trendelenburg (head down) and reverse Trendelenburg (head up) position on respiratory and cardiovascular function in anaesthetized horses. Vet Anaesth Analg 2018; 45:760-771. [DOI: 10.1016/j.vaa.2018.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/26/2017] [Accepted: 01/09/2018] [Indexed: 01/23/2023]
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36
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De Souza LA, Ferreira JB, Schein ASDO, Dartora DR, Casali AG, Scassola CMC, Tobaldini E, Montano N, Guzzetti S, Porta A, Irigoyen MC, Casali KR. Optimization of Vagal Stimulation Protocol Based on Spontaneous Breathing Rate. Front Physiol 2018; 9:1341. [PMID: 30319449 PMCID: PMC6168675 DOI: 10.3389/fphys.2018.01341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/05/2018] [Indexed: 11/13/2022] Open
Abstract
Controlled breathing maneuver is being widely applied for cardiovascular autonomic control evaluation and cardiac vagal activation through reduction of breathing rate (BR). However, this maneuver presented contradictory results depending on the protocol and the chosen BR. These variations may be related to the individual intrinsic profile baseline sympathetic tonus, as described before by others. In this study, we evaluated the effect of controlled breathing maneuver on cardiovascular autonomic control in 26 healthy subjects allocated into two protocols: (1) controlled breathing in three different rates (10, 15, and 20 breaths/min) and (2) controlled breathing in rates normalized by the individual spontaneous breathing rate (SBR) at 100, 80, 70, and 50%. Our results showed autonomic responses favorable to vagal modulation with the lower BR maneuvers. Nevertheless, while this activation was variable using the standard protocol, all participants of the normalized protocol demonstrated an increase of vagal modulation at 80% BR (HFnu 80 = 67.5% vs. 48.2%, p < 0.0001). These results suggest that controlled breathing protocols to induce vagal activation should consider the SBR, being limited to values moderately lower than the baseline.
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Affiliation(s)
- Liliane Appratto De Souza
- Institute of Cardiology of Rio Grande do Sul, University Foundation of Cardiology, Porto Alegre, Brazil
| | | | | | - Daniela Ravizzoni Dartora
- Institute of Cardiology of Rio Grande do Sul, University Foundation of Cardiology, Porto Alegre, Brazil
| | - Adenauer Girardi Casali
- Department of Science and Technology, Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, Brazil
| | - Catharina M Carvalho Scassola
- Department of Science and Technology, Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, Brazil
| | - Eleonora Tobaldini
- Department of Clinical Science, Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Nicola Montano
- Department of Clinical Science, Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Stefano Guzzetti
- Department of Clinical Science, Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.,Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Maria Claudia Irigoyen
- Institute of Cardiology of Rio Grande do Sul, University Foundation of Cardiology, Porto Alegre, Brazil.,Hypertension Division, Medicine School, Heart Institute, São Paulo University, São Paulo, Brazil
| | - Karina Rabello Casali
- Institute of Cardiology of Rio Grande do Sul, University Foundation of Cardiology, Porto Alegre, Brazil.,Department of Science and Technology, Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, Brazil
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Fornasiero A, Savoldelli A, Skafidas S, Stella F, Bortolan L, Boccia G, Zignoli A, Schena F, Mourot L, Pellegrini B. Delayed parasympathetic reactivation and sympathetic withdrawal following maximal cardiopulmonary exercise testing (CPET) in hypoxia. Eur J Appl Physiol 2018; 118:2189-2201. [PMID: 30051338 DOI: 10.1007/s00421-018-3945-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/13/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE This study investigated the effects of acute hypoxic exposure on post-exercise cardiac autonomic modulation following maximal cardiopulmonary exercise testing (CPET). METHODS Thirteen healthy men performed CPET and recovery in normoxia (N) and normobaric hypoxia (H) (FiO2 = 13.4%, ≈ 3500 m). Post-exercise cardiac autonomic modulation was assessed during recovery (300 s) through the analysis of fast-phase and slow-phase heart rate recovery (HRR) and heart rate variability (HRV) indices. RESULTS Both short-term, T30 (mean difference (MD) 60.0 s, 95% CI 18.2-101.8, p = 0.009, ES 1.01), and long-term, HRRt (MD 21.7 s, 95% CI 4.1-39.3, p = 0.020, ES 0.64), time constants of HRR were higher in H. Fast-phase (30 and 60 s) and slow-phase (300 s) HRR indices were reduced in H either when expressed in bpm or in percentage of HRpeak (p < 0.05). Chronotropic reserve recovery was lower in H than in N at 30 s (MD - 3.77%, 95% CI - 7.06 to - 0.49, p = 0.028, ES - 0.80) and at 60 s (MD - 7.23%, 95% CI - 11.45 to - 3.01, p = 0.003, ES - 0.81), but not at 300 s (p = 0.436). Concurrently, Ln-RMSSD was reduced in H at 60 and 90 s (p < 0.01) but not at other time points during recovery (p > 0.05). CONCLUSIONS Affected fast-phase, slow-phase HRR and HRV indices suggested delayed parasympathetic reactivation and sympathetic withdrawal after maximal exercise in hypoxia. However, a similar cardiac autonomic recovery was re-established within 5 min after exercise cessation. These findings have several implications in cardiac autonomic recovery interpretation and in HR assessment in response to high-intensity hypoxic exercise.
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Affiliation(s)
- Alessandro Fornasiero
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy. .,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Aldo Savoldelli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Spyros Skafidas
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Federico Stella
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Lorenzo Bortolan
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Gennaro Boccia
- NeuroMuscularFunction Research Group, Department of Medical Sciences, School of Exercise and Sport Sciences, University of Turin, Turin, Italy
| | - Andrea Zignoli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy
| | - Federico Schena
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Laurent Mourot
- Laboratory of Prognostic Markers and Regulatory Factors of Cardiovascular Diseases and Exercise Performance, Health, Innovation Platform (EA 3920), University of Bourgogne Franche-Comté, Besançon, France.,Tomsk Polytechnic University, Tomsk, Russia
| | - Barbara Pellegrini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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Morgan BJ, Teodorescu M, Pegelow DF, Jackson ER, Schneider DL, Plante DT, Gapinski JP, Hetzel SJ, Dopp JM. Effects of losartan and allopurinol on cardiorespiratory regulation in obstructive sleep apnoea. Exp Physiol 2018; 103:941-955. [PMID: 29750475 DOI: 10.1113/ep087006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/08/2018] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the central question of this study? In sleep apnoea, a putative link between intermittent hypoxia and hypertension is the generation of oxygen radicals by angiotensin II and xanthine oxidase within the chemoreflex arc and vasculature. We tested whether chemoreflex control of sympathetic outflow, hypoxic vasodilatation and blood pressure are altered by angiotensin blockade (losartan) and/or xanthine oxidase inhibition (allopurinol). What is the main finding and its importance? Both drugs lowered blood pressure without altering sympathetic outflow, reducing chemoreflex sensitivity or enhancing hypoxic vasodilatation. Losartan and allopurinol are effective therapies for achieving blood pressure control in sleep apnoea. ABSTRACT Chemoreflex sensitization produced by chronic intermittent hypoxia in rats is attenuated by angiotensin II type 1 receptor (AT1 R) blockade. Both AT1 R blockade and xanthine oxidase inhibition ameliorate chronic intermittent hypoxia-induced endothelial dysfunction. We hypothesized that treatment with losartan and allopurinol would reduce chemoreflex sensitivity and improve hypoxic vasodilatation in patients with obstructive sleep apnoea. Eighty-six hypertensive patients with apnoea-hypopnoea index ≥25 events h-1 and no other cardiovascular, pulmonary, renal or metabolic disease were randomly assigned to receive allopurinol, losartan or placebo for 6 weeks. Treatment with other medications and/or continuous positive airway pressure remained unchanged. Tests of chemoreflex sensitivity and hypoxic vasodilatation were performed during wakefulness before and after treatment. Ventilation (pneumotachography), muscle sympathetic nerve activity (microneurography), heart rate (electrocardiography), arterial oxygen saturation (pulse oximetry), blood pressure (sphygmomanometry), forearm blood flow (venous occlusion plethysmography) and cerebral flow velocity (transcranial Doppler ultrasound) were measured during eupnoeic breathing and graded reductions in inspired O2 tension. Losartan and allopurinol lowered arterial pressure measured during eupnoeic breathing and exposure to acute hypoxia. Neither drug altered the slopes of ventilatory, sympathetic or cardiovascular responses to acute hypoxia. We conclude that losartan and allopurinol are viable pharmacotherapeutic adjuncts for achieving blood pressure control in hypertensive obstructive sleep apnoea patients, even those who are adequately treated with continuous positive airway pressure.
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Affiliation(s)
- Barbara J Morgan
- Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, WI, USA
| | - Mihaela Teodorescu
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - David F Pegelow
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, USA
| | - Emily R Jackson
- Pharmacy Practice Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
| | - Devin L Schneider
- Pharmacy Practice Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
| | - David T Plante
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Scott J Hetzel
- Department of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - John M Dopp
- Pharmacy Practice Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
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Sackett JR, Schlader ZJ, Sarker S, Chapman CL, Johnson BD. Peripheral chemosensitivity is not blunted during 2 h of thermoneutral head out water immersion in healthy men and women. Physiol Rep 2018; 5:5/20/e13472. [PMID: 29051306 PMCID: PMC5661233 DOI: 10.14814/phy2.13472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 09/17/2017] [Indexed: 11/24/2022] Open
Abstract
Carbon dioxide (CO2) retention occurs during water immersion, but it is not known if peripheral chemosensitivity is altered during water immersion, which could contribute to CO2 retention. We tested the hypothesis that peripheral chemosensitivity to hypercapnia and hypoxia is blunted during 2 h of thermoneutral head out water immersion (HOWI) in healthy young adults. Peripheral chemosensitivity was assessed by the ventilatory, heart rate, and blood pressure responses to hypercapnia and hypoxia at baseline, 10, 60, 120 min, and post HOWI and a time‐control visit (control). Subjects inhaled 1 breath of 13% CO2, 21% O2, and 66% N2 to test peripheral chemosensitivity to hypercapnia and 2–6 breaths of 100% N2 to test peripheral chemosensitivity to hypoxia. Each gas was administered four separate times at each time point. Partial pressure of end‐tidal CO2 (PETCO2), arterial oxygen saturation (SpO2), ventilation, heart rate, and blood pressure were recorded continuously. Ventilation was higher during HOWI versus control at post (P = 0.037). PETCO2 was higher during HOWI versus control at 10 min (46 ± 2 vs. 44 ± 2 mmHg), 60 min (46 ± 2 vs. 44 ± 2 mmHg), and 120 min (46 ± 3 vs. 43 ± 3 mmHg) (all P < 0.001). Ventilatory (P = 0.898), heart rate (P = 0.760), and blood pressure (P = 0.092) responses to hypercapnia were not different during HOWI versus control at any time point. Ventilatory (P = 0.714), heart rate (P = 0.258), and blood pressure (P = 0.051) responses to hypoxia were not different during HOWI versus control at any time point. These data indicate that CO2 retention occurs during thermoneutral HOWI despite no changes in peripheral chemosensitivity.
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Affiliation(s)
- James R Sackett
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Zachary J Schlader
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Suman Sarker
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Christopher L Chapman
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Blair D Johnson
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
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Kuwabara M, Tomitani N, Shiga T, Kario K. Polysomnography-derived sleep parameters as a determinant of nocturnal blood pressure profile in patients with obstructive sleep apnea. J Clin Hypertens (Greenwich) 2018; 20:1039-1048. [DOI: 10.1111/jch.13308] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 03/13/2018] [Accepted: 03/28/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Mitsuo Kuwabara
- Division of Cardiovascular Medicine; Department of Medicine; Jichi Medical University School of Medicine; Tochigi Japan
- Omron Healthcare Co., Ltd.; Kyoto Japan
| | - Naoko Tomitani
- Division of Cardiovascular Medicine; Department of Medicine; Jichi Medical University School of Medicine; Tochigi Japan
| | - Toshikazu Shiga
- Division of Cardiovascular Medicine; Department of Medicine; Jichi Medical University School of Medicine; Tochigi Japan
- Omron Healthcare Co., Ltd.; Kyoto Japan
| | - Kazuomi Kario
- Division of Cardiovascular Medicine; Department of Medicine; Jichi Medical University School of Medicine; Tochigi Japan
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41
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Roder F, Strotmann J, Fox H, Bitter T, Horstkotte D, Oldenburg O. Interactions of Sleep Apnea, the Autonomic Nervous System, and Its Impact on Cardiac Arrhythmias. CURRENT SLEEP MEDICINE REPORTS 2018. [DOI: 10.1007/s40675-018-0117-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Weippert M, Behrens M, Mau-Moeller A, Bruhn S, Behrens K. Cycling before and after Exhaustion Differently Affects Cardiac Autonomic Control during Heart Rate Matched Exercise. Front Physiol 2017; 8:844. [PMID: 29163192 PMCID: PMC5671980 DOI: 10.3389/fphys.2017.00844] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/10/2017] [Indexed: 11/17/2022] Open
Abstract
During cycling before (PRE) and after exhaustion (POST) different modes of autonomic cardiac control might occur due to different interoceptive input and altered influences from higher brain centers. We hypothesized that heart rate variability (HRV) is significantly affected by an interaction of the experimental period (PRE vs. POST) and exercise intensity (HIGH vs. LOW; HIGH = HR > HR at the lactate threshold (HRLT), LOW = HR ≤ HRLT) despite identical average HR. Methods: Fifty healthy volunteers completed an incremental cycling test until exhaustion. Workload started with 30 W at a constant pedaling rate (60 revolutions · min−1) and was gradually increased by 30 W · 5 min−1. Five adjacent 60 s inter-beat (R-R) interval segments from the immediate recovery period (POST 1–5 at 30 W and 60 rpm) were each matched with their HR-corresponding 60 s-segments during the cycle test (PRE 1–5). An analysis of covariance was carried out with one repeated-measures factor (PRE vs. POST exhaustion), one between-subject factor (HIGH vs. LOW intensity) and respiration rate as covariate to test for significant effects (p < 0.050) on the natural log-transformed root mean square of successive differences between adjacent R-R intervals (lnRMSSD60s). Results: LnRMSSD60s was significantly affected by the interaction of experimental period × intensity [F(1, 242) = 30.233, p < 0.001, ηp2 = 0.111]. LnRMSSD60s was higher during PRE compared to POST at LOW intensity (1.6 ± 0.6 vs. 1.4 ± 0.6 ms; p < 0.001). In contrast, at HIGH intensity lnRMSSD60s was lower during PRE compared to POST (1.0 ± 0.4 vs. 1.2 ± 0.4 ms; p < 0.001). Conclusion: Identical net HR during cycling can result from distinct autonomic modulation patterns. Results suggest a pronounced sympathetic-parasympathetic coactivation immediately after the cessation of peak workload compared to HR-matched cycling before exhaustion at HIGH intensity. On the opposite, at LOW intensity cycling, a stronger coactivational cardiac autonomic modulation pattern occurs during PRE-exhaustion if compared to POST-exhaustion cycling. The different autonomic modes during these phases might be the result of different afferent and/or central inputs to the cardiovascular control centers in the brainstem.
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Affiliation(s)
| | - Martin Behrens
- Institute of Sport Science, University of Rostock, Rostock, Germany
| | - Anett Mau-Moeller
- Institute of Sport Science, University of Rostock, Rostock, Germany.,Department of Orthopaedics, Rostock University Medical Center, Rostock, Germany
| | - Sven Bruhn
- Institute of Sport Science, University of Rostock, Rostock, Germany
| | - Kristin Behrens
- Institute of Sport Science, University of Rostock, Rostock, Germany
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Fisher JP, Flück D, Hilty MP, Lundby C. Carotid chemoreceptor control of muscle sympathetic nerve activity in hypobaric hypoxia. Exp Physiol 2017; 103:77-89. [DOI: 10.1113/ep086493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/12/2017] [Indexed: 12/16/2022]
Affiliation(s)
- James P. Fisher
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences; University of Birmingham; Edgbaston Birmingham UK
| | - Daniela Flück
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences; University of British Columbia - Okanagan; Kelowna British Columbia Canada
- Zurich Center for Integrative Human Physiology (ZIHP), Institute of Physiology; University of Zurich; Switzerland
| | - Matthias P. Hilty
- Intensive Care Unit; University Hospital of Zürich; Zürich Switzerland
| | - Carsten Lundby
- Zurich Center for Integrative Human Physiology (ZIHP), Institute of Physiology; University of Zurich; Switzerland
- Center for Physical Activity Research (CFAS); University Hospital of Copenhagen; Copenhagen Denmark
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44
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Endothelin contributes to the blood pressure rise triggered by hypoxia in severe obstructive sleep apnea. J Hypertens 2017; 35:118-124. [PMID: 27906839 DOI: 10.1097/hjh.0000000000001134] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Obstructive sleep apnea (OSA) is strongly correlated with an increased risk of systemic hypertension. However, the link between systemic hypertension and nocturnal apneas remains incompletely understood. Animal studies suggest an implication of the endothelin system. The aim of the present study is to determine if endogenous endothelin plays a role in the increase in blood pressure observed during hypoxic episodes in OSA patients, in addition to peripheral chemoreflex and neural sympathetic activation. METHODS We assessed the effects of the nonspecific endothelin antagonist bosentan (500 mg; Tracleer; Actelion; Basel, Switzerland) on ventilation, hemodynamics, and muscle sympathetic nerve activity (MSNA) during normoxia and isocapnic hypoxia using a randomized, crossover, double-blinded, placebo-controlled study design, and in 13 severely untreated sleep apneic patients (age 50 ± 9 years, apnea-hypopnea index 35 ± 21/h). RESULTS Hypoxia increased blood pressure, MSNA, and minute ventilation as oxygen saturation decreased. Bosentan suppressed completely the increase in SBP during a 5-min hypoxic challenge (143 ± 5 mmHg during hypoxia vs. 133 ± 5 mmHg during normoxia with placebo and 127 ± 3 mmHg during hypoxia vs. 125 ± 3 mmHg during normoxia under bosentan, P = 0.023). DBP as well as the rise in MSNA and ventilation during isocapnic hypoxia did not differ between bosentan and placebo. CONCLUSION Endothelin contributes to the rise in SBP in response to acute hypoxia in patients with severely untreated OSA. This was not due to lower chemoreflex activation with bosentan.
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Lundby C, Calbet J, van Hall G, Saltin B, Sander M. Sustained sympathetic activity in altitude acclimatizing lowlanders and high-altitude natives. Scand J Med Sci Sports 2017; 28:854-861. [DOI: 10.1111/sms.12976] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2017] [Indexed: 12/12/2022]
Affiliation(s)
- C. Lundby
- Copenhagen Muscle Research Centre (CMRC); Rigshospitalet; Copenhagen Denmark
- Center for Physical Activity Research; Rigshospitalet; Copenhagen Denmark
| | - J. Calbet
- Copenhagen Muscle Research Centre (CMRC); Rigshospitalet; Copenhagen Denmark
- Department of Physical Education; Research Institute of Biomedical and Health Sciences (IUIBS); University of Las Palmas de Gran Canaria; Las Palmas Spain
| | - G. van Hall
- Copenhagen Muscle Research Centre (CMRC); Rigshospitalet; Copenhagen Denmark
- Endocrinology Research Section; Rigshospitalet; Copenhagen Denmark
| | - B. Saltin
- Copenhagen Muscle Research Centre (CMRC); Rigshospitalet; Copenhagen Denmark
| | - M. Sander
- Copenhagen Muscle Research Centre (CMRC); Rigshospitalet; Copenhagen Denmark
- Kardiologisk Afdeling Y; Bispebjerg Hospital; Copenhagen Denmark
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Review of and Updates on Hypertension in Obstructive Sleep Apnea. Int J Hypertens 2017; 2017:1848375. [PMID: 29147581 PMCID: PMC5632858 DOI: 10.1155/2017/1848375] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/17/2017] [Indexed: 12/19/2022] Open
Abstract
Obstructive sleep apnea (OSA) is a prevalent sleep disorder as is hypertension (HTN) in the 21st century with the rising incidence of obesity. Numerous studies have shown a strong association of OSA with cardiovascular morbidity and mortality. There is overwhelming evidence supporting the relationship between OSA and hypertension (HTN). The pathophysiology of HTN in OSA is complex and dependent on various factors such as sympathetic tone, renin-angiotensin-aldosterone system, endothelial dysfunction, and altered baroreceptor reflexes. The treatment of OSA is multifactorial ranging from CPAP to oral appliances to lifestyle modifications to antihypertensive drugs. OSA and HTN both need prompt diagnosis and treatment to help address the growing cardiovascular morbidity and mortality due to these two entities.
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Badrov MB, Barak OF, Mijacika T, Shoemaker LN, Borrell LJ, Lojpur M, Drvis I, Dujic Z, Shoemaker JK. Ventilation inhibits sympathetic action potential recruitment even during severe chemoreflex stress. J Neurophysiol 2017; 118:2914-2924. [PMID: 28835525 PMCID: PMC5686238 DOI: 10.1152/jn.00381.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 01/26/2023] Open
Abstract
This study investigated the influence of ventilation on sympathetic action potential (AP) discharge patterns during varying levels of high chemoreflex stress. In seven trained breath-hold divers (age 33 ± 12 yr), we measured muscle sympathetic nerve activity (MSNA) at baseline, during preparatory rebreathing (RBR), and during 1) functional residual capacity apnea (FRCApnea) and 2) continued RBR. Data from RBR were analyzed at matched (i.e., to FRCApnea) hemoglobin saturation (HbSat) levels (RBRMatched) or more severe levels (RBREnd). A third protocol compared alternating periods (30 s) of FRC and RBR (FRC-RBRALT). Subjects continued each protocol until 85% volitional tolerance. AP patterns in MSNA (i.e., providing the true neural content of each sympathetic burst) were studied using wavelet-based methodology. First, for similar levels of chemoreflex stress (both HbSat: 71 ± 6%; P = NS), RBRMatched was associated with reduced AP frequency and APs per burst compared with FRCApnea (both P < 0.001). When APs were binned according to peak-to-peak amplitude (i.e., into clusters), total AP clusters increased during FRCApnea (+10 ± 2; P < 0.001) but not during RBRMatched (+1 ± 2; P = NS). Second, despite more severe chemoreflex stress during RBREnd (HbSat: 56 ± 13 vs. 71 ± 6%; P < 0.001), RBREnd was associated with a restrained increase in the APs per burst (FRCApnea: +18 ± 7; RBREnd: +11 ± 5) and total AP clusters (FRCApnea: +10 ± 2; RBREnd: +6 ± 4) (both P < 0.01). During FRC-RBRALT, all periods of FRC elicited sympathetic AP recruitment (all P < 0.001), whereas all periods of RBR were associated with complete withdrawal of AP recruitment (all P = NS). Presently, we demonstrate that ventilation per se restrains and/or inhibits sympathetic axonal recruitment during high, and even extreme, chemoreflex stress.NEW & NOTEWORTHY The current study demonstrates that the sympathetic neural recruitment patterns observed during chemoreflex activation induced by rebreathing or apnea are restrained and/or inhibited by the act of ventilation per se, despite similar, or even greater, levels of severe chemoreflex stress. Therefore, ventilation modulates not only the timing of sympathetic bursts but also the within-burst axonal recruitment normally observed during progressive chemoreflex stress.
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Affiliation(s)
- Mark B Badrov
- School of Kinesiology, Western University, London, Ontario, Canada
| | - Otto F Barak
- Department of Physiology, University of Split School of Medicine, Split, Croatia.,Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Tanja Mijacika
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | | | | | - Mihajlo Lojpur
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - Ivan Drvis
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia; and
| | - Zeljko Dujic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - J Kevin Shoemaker
- School of Kinesiology, Western University, London, Ontario, Canada; .,Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
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Eckberg DL, Cooke WH, Diedrich A, Biaggioni I, Buckey JC, Pawelczyk JA, Ertl AC, Cox JF, Kuusela TA, Tahvanainen KUO, Mano T, Iwase S, Baisch FJ, Levine BD, Adams-Huet B, Robertson D, Blomqvist CG. Respiratory modulation of human autonomic function on Earth. J Physiol 2016; 594:5611-27. [PMID: 27028958 PMCID: PMC5043049 DOI: 10.1113/jp271654] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/14/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We studied healthy supine astronauts on Earth with electrocardiogram, non-invasive arterial pressure, respiratory carbon dioxide concentrations, breathing depth and sympathetic nerve recordings. The null hypotheses were that heart beat interval fluctuations at usual breathing frequencies are baroreflex mediated, that they persist during apnoea, and that autonomic responses to apnoea result from changes of chemoreceptor, baroreceptor or lung stretch receptor inputs. R-R interval fluctuations at usual breathing frequencies are unlikely to be baroreflex mediated, and disappear during apnoea. The subjects' responses to apnoea could not be attributed to changes of central chemoreceptor activity (hypocapnia prevailed); altered arterial baroreceptor input (vagal baroreflex gain declined and muscle sympathetic nerve burst areas, frequencies and probabilities increased, even as arterial pressure climbed to new levels); or altered pulmonary stretch receptor activity (major breathing frequency and tidal volume changes did not alter vagal tone or sympathetic activity). Apnoea responses of healthy subjects may result from changes of central respiratory motoneurone activity. ABSTRACT We studied eight healthy, supine astronauts on Earth, who followed a simple protocol: they breathed at fixed or random frequencies, hyperventilated and then stopped breathing, as a means to modulate and expose to view important, but obscure central neurophysiological mechanisms. Our recordings included the electrocardiogram, finger photoplethysmographic arterial pressure, tidal volume, respiratory carbon dioxide concentrations and peroneal nerve muscle sympathetic activity. Arterial pressure, vagal tone and muscle sympathetic outflow were comparable during spontaneous and controlled-frequency breathing. Compared with spontaneous, 0.1 and 0.05 Hz breathing, however, breathing at usual frequencies (∼0.25 Hz) lowered arterial baroreflex gain, and provoked smaller arterial pressure and R-R interval fluctuations, which were separated by intervals that were likely to be too short and variable to be attributed to baroreflex physiology. R-R interval fluctuations at usual breathing frequencies disappear during apnoea, and thus cannot provide evidence for the existence of a central respiratory oscillation. Apnoea sets in motion a continuous and ever changing reorganization of the relations among stimulatory and inhibitory inputs and autonomic outputs, which, in our study, could not be attributed to altered chemoreceptor, baroreceptor, or pulmonary stretch receptor activity. We suggest that responses of healthy subjects to apnoea are driven importantly, and possibly prepotently, by changes of central respiratory motoneurone activity. The companion article extends these observations and asks the question, Might terrestrial responses to our 20 min breathing protocol find expression as long-term neuroplasticity in serial measurements made over 20 days during and following space travel?
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Affiliation(s)
- Dwain L Eckberg
- Departments of Medicine and Physiology, Hunter Holmes McGuire Department of Veterans Affairs, Medical Center and Virginia Commonwealth University School of Medicine, Richmond, VA, USA.
| | - William H Cooke
- Department of Kinesiology, Health, and Nutrition, University of Texas at San Antonio, San Antonio, TX, USA
| | - André Diedrich
- Department of Medicine, Division of Clinical Pharmacology, Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Italo Biaggioni
- Department of Medicine, Division of Clinical Pharmacology, Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Jay C Buckey
- Dartmouth Hitchcock Medical Center, Lebanon, NH, USA
| | - James A Pawelczyk
- Department of Physiology, Pennsylvania State University, University Park and Hershey, PA, USA
| | - Andrew C Ertl
- Department of Medicine, Division of Clinical Pharmacology, Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - James F Cox
- Departments of Medicine and Physiology, Hunter Holmes McGuire Department of Veterans Affairs, Medical Center and Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Tom A Kuusela
- Department of Physics, University of Turku, Turku, Finland
| | - Kari U O Tahvanainen
- Department of Clinical Physiology and Nuclear Medicine, South Karelia Central Hospital, Lappeenranta, Finland
| | - Tadaaki Mano
- Gifu University of Medical Science, 795-1 Nagamine Ichihiraga, Seki, Gifu, 501-3892, Japan
| | - Satoshi Iwase
- Department of Physiology, Aichi Medical University, Aichi, Japan
| | | | - Benjamin D Levine
- Department of Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA
| | | | - David Robertson
- Department of Medicine, Division of Clinical Pharmacology, Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - C Gunnar Blomqvist
- Department of Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
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Ventricular assist devices and sleep-disordered breathing. Sleep Med Rev 2016; 35:51-61. [PMID: 27641662 DOI: 10.1016/j.smrv.2016.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 08/16/2016] [Accepted: 08/17/2016] [Indexed: 11/22/2022]
Abstract
Congestive heart failure is one of the leading causes of morbidity and mortality in the United States, and left ventricular assist devices have revolutionized treatment of end-stage heart failure. Given that sleep apnea results in significant morbidity in these patients with advanced heart failure, practicing sleep physicians need to have an understanding of left ventricular assist devices. In this review, we summarize what is known about ventricular assist devices as they relate to sleep medicine.
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Badrov MB, Lalande S, Olver TD, Suskin N, Shoemaker JK. Effects of aging and coronary artery disease on sympathetic neural recruitment strategies during end-inspiratory and end-expiratory apnea. Am J Physiol Heart Circ Physiol 2016; 311:H1040-H1050. [PMID: 27542408 DOI: 10.1152/ajpheart.00334.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 08/17/2016] [Indexed: 11/22/2022]
Abstract
In response to acute physiological stress, the sympathetic nervous system modifies neural outflow through increased firing frequency of lower-threshold axons, recruitment of latent subpopulations of higher-threshold axons, and/or acute modifications of synaptic delays. Aging and coronary artery disease (CAD) often modify efferent muscle sympathetic nerve activity (MSNA). Therefore, we investigated whether CAD (n = 14; 61 ± 10 yr) and/or healthy aging without CAD (OH; n = 14; 59 ± 9 yr) modified these recruitment strategies that normally are observed in young healthy (YH; n = 14; 25 ± 3 yr) individuals. MSNA (microneurography) was measured at baseline and during maximal voluntary end-inspiratory (EI) and end-expiratory (EE) apneas. Action potential (AP) patterns were studied using a novel AP analysis technique. AP frequency increased in all groups during both EI- and EE-apnea (all P < 0.05). The mean AP content per integrated burst increased during EI- and EE-apnea in YH (EI: Δ6 ± 4 APs/burst; EE: Δ10 ± 6 APs/burst; both P < 0.01) and OH (EI: Δ3 ± 3 APs/burst; EE: Δ4 ± 5 APs/burst; both P < 0.01), but not in CAD (EI: Δ1 ± 3 APs/burst; EE: Δ2 ± 3 APs/burst; both P = NS). When APs were binned into "clusters" according to peak-to-peak amplitude, total clusters increased during EI- and EE-apnea in YH (EI: Δ5 ± 2; EE: Δ6 ± 4; both P < 0.01), during EI-apnea only in OH (EI: Δ1 ± 2; P < 0.01; EE: Δ1 ± 2; P = NS), and neither apnea in CAD (EI: Δ -2 ± 2; EE: Δ -1 ± 2; both P = NS). In all groups, the AP cluster size-latency profile was shifted downwards for every corresponding cluster during EI- and EE-apnea (all P < 0.01). As such, inherent dysregulation exists within the central features of apnea-related sympathetic outflow in aging and CAD.
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Affiliation(s)
- Mark B Badrov
- School of Kinesiology, Western University, London, Ontario, Canada
| | - Sophie Lalande
- School of Kinesiology, Western University, London, Ontario, Canada; Department of Kinesiology, University of Toledo, Toledo, Ohio
| | - T Dylan Olver
- School of Kinesiology, Western University, London, Ontario, Canada
| | - Neville Suskin
- Cardiac Rehabilitation and Secondary Prevention Program of St. Joseph's Health Care London, London, Ontario, Canada; Department of Medicine (Cardiology) and Program of Experimental Medicine, Western University, London, Ontario, Canada; and
| | - J Kevin Shoemaker
- School of Kinesiology, Western University, London, Ontario, Canada; Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
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