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Yu J. Research journey into multiple-sensor theory. J Neurophysiol 2023; 130:128-138. [PMID: 37341418 DOI: 10.1152/jn.00062.2023] [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: 02/06/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/22/2023] Open
Abstract
In 1998, I was asked by the American Physiological Society to review a book written by Dr. Michael de Burgh Daly, Peripheral Arterial Chemoreceptors and Respiratory-Cardiovascular Integration. Inspired by this work, I came to appreciate how researchers in the later stages of their careers and who provide a detailed review of their experimental approach might effectively contribute to science, especially to the benefit of young scientists (Yu J. The Physiologist 41: 231, 1998.). This article is written in that vein. Over several decades of intensive investigation of cardiopulmonary reflexes, focused on the sensory receptors, my colleagues and I advanced a novel multiple-sensor theory (MST) to explain the role of the vagal mechanosensory system. Described here is our research journey through various stages of developing MST and the process of how the problem was identified, approached, and tackled. MST redefines conventional mechanosensor doctrines and is supported by new studies that clarify a century of research data. It entails reinterpretation of many established findings. Hopefully, this article will benefit young scientists, such as graduate and postdoctoral students in the cardiopulmonary sensory research field.
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Affiliation(s)
- Jerry Yu
- Department of Pulmonary Medicine, University of Louisville, Louisville, Kentucky, United States
- Robley Rex VA Medical Center, Louisville, Kentucky, United States
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Abstract
This chapter broadly reviews cardiopulmonary sympathetic and vagal sensors and their reflex functions during physiologic and pathophysiologic processes. Mechanosensory operating mechanisms, including their central projections, are described under multiple sensor theory. In addition, ways to interpret evidence surrounding several controversial issues are provided, with detailed reasoning on how conclusions are derived. Cardiopulmonary sensory roles in breathing control and the development of symptoms and signs and pathophysiologic processes in cardiopulmonary diseases (such as cough and neuroimmune interaction) also are discussed.
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Affiliation(s)
- Jerry Yu
- Department of Medicine (Pulmonary), University of Louisville, and Robley Rex VA Medical Center, Louisville, KY, United States.
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Ministro G, Castaño JB, Barboza CA, Moura EG, Ferreira-Melo SE, Mostarda CT, Fattori A, Moreno-Junior H, Rodrigues B. ACUTE TRANSCRANIAL DIRECT CURRENT STIMULATION (tDCS) IMPROVES VENTILATORY VARIABILITY AND AUTONOMIC MODULATION IN RESISTANT HYPERTENSIVE PATIENTS. Respir Physiol Neurobiol 2021; 297:103830. [PMID: 34915178 DOI: 10.1016/j.resp.2021.103830] [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] [Received: 10/25/2021] [Revised: 11/29/2021] [Accepted: 12/13/2021] [Indexed: 10/19/2022]
Abstract
Here, we assessed the impact of one session of transcranial direct current stimulation (tDCS) or SHAM (20 min, each) on ventilatory responses to cardiopulmonary exercise test, central and peripheral blood pressure (BP), and autonomic modulation in resistant hypertensive (RHT) patients. RHT subjects (n = 13) were randomly submitted to SHAM and tDCS crossing sessions (1 week of "washout"). Patients and a technician who set the tDCS/Sham room up were both blind. After brain stimulation, patients were submitted to a cardiopulmonary exercise test to evaluate ventilatory and cardiovascular response to exercise. Hemodynamic (Finometer®, Beatscope), and autonomic variables were measured at baseline (before tDCS/Sham) and after incremental exercise. RESULTS: Our study shows that tDCS condition improved heart rate recovery, VO2 peak, and vagal modulation (after cardiopulmonary exercise test); attenuated the ventilatory variability response, central and peripheral blood pressure well as sympathetic modulation (after cardiopulmonary exercise test) in comparison with SHAM. These data suggest that acute tDCS sessions prevented oscillatory ventilation behavior during the cardiopulmonary exercise test and mitigated the increase of systolic blood pressure in RHT patients. After the exercise test, tDCS promotes better vagal reentry and improved autonomic modulation, possibly reducing central blood pressure and aortic augmentation index compared to SHAM. Brazilian Registry of Clinical Trials (ReBEC): https://ensaiosclinicos.gov.br/rg/RBR-8n7c9p.
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Affiliation(s)
- Gabriela Ministro
- Laboratory of Cardiovascular Investigation & Exercise, School of Physical Education, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Javier B Castaño
- Laboratory of Cardiovascular Investigation & Exercise, School of Physical Education, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Catarina A Barboza
- Laboratory of Cardiovascular Investigation & Exercise, School of Physical Education, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Eliezer G Moura
- Laboratory of Cardiovascular Investigation & Exercise, School of Physical Education, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Silvia E Ferreira-Melo
- Laboratory of Cardiovascular Pharmacology & Hypertension, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | | | - André Fattori
- Department of Clinical Medicine, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Heitor Moreno-Junior
- Laboratory of Cardiovascular Pharmacology & Hypertension, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Bruno Rodrigues
- Laboratory of Cardiovascular Investigation & Exercise, School of Physical Education, University of Campinas (UNICAMP), Campinas, SP, Brazil; Laboratory of Cardiovascular Pharmacology & Hypertension, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Walker JF, Yu J. A direct injection technique for investigation of lung sensory properties and reflex functions. Exp Physiol 2021; 106:1449-1459. [PMID: 33719104 DOI: 10.1113/ep089261] [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] [Received: 01/06/2021] [Accepted: 03/08/2021] [Indexed: 12/18/2022]
Abstract
NEW FINDINGS This article reviews a unique direct injection technique that complements the more conventional right atrial injection and aerosol delivery methods to study sensory and reflex effects of the lung sensors. Used in combination with other methods, this technique should contribute to the pulmonary sensory research. ABSTRACT The lungs house sensory receptors (sensors) that mediate a variety of sensory and reflex responses to mechanical or chemical changes. These reflexes are mainly carried through pulmonary sympathetic and vagal afferent pathways. The chemosensors in the lung periphery are especially important in pulmonary diseases and their reflex responses have traditionally been studied either by aerosol delivery, which also activates receptors in the central airways, or by right atrial injection, which also activates receptors lying outside the lung. Thus, these techniques may confound the interpretation of sensory function. Our laboratory has developed a direct injection technique to deliver agents into the lung parenchyma, which complements the conventional techniques with some important advantages. This article reviews the technique.
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Affiliation(s)
- Jerome F Walker
- Department of Respiratory Therapy, Bellarmine University, Louisville, KY, USA.,Robley Rex VA Medical Center, Louisville, KY, USA
| | - Jerry Yu
- Robley Rex VA Medical Center, Louisville, KY, USA.,Pulmonary Division, Department of Medicine, University of Louisville, Louisville, KY, USA
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Agostoni P, Emdin M, De Martino F, Apostolo A, Masè M, Contini M, Carriere C, Vignati C, Sinagra G. Roles of periodic breathing and isocapnic buffering period during exercise in heart failure. Eur J Prev Cardiol 2021; 27:19-26. [PMID: 33238742 PMCID: PMC7691624 DOI: 10.1177/2047487320952029] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In heart failure, exercise - induced periodic breathing and end tidal carbon dioxide pressure value during the isocapnic buffering period are two features identified at cardiopulmonary exercise testing strictly related to sympathetic activation. In the present review we analysed the physiology behind periodic breathing and the isocapnic buffering period and present the relevant prognostic value of both periodic breathing and the presence/absence of the identifiable isocapnic buffering period.
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Affiliation(s)
- Piergiuseppe Agostoni
- Centro Cardiologico Monzino, IRCCS, Italy.,Department of Clinical Sciences and Community Health, University of Milano, Italy
| | - Michele Emdin
- Life Science Institute, Scuola Superiore Sant'Anna, Italy.,Fondazione Gabriele Monasterio, CNR-Regione Toscana, Italy
| | | | | | - Marco Masè
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Italy
| | | | - Cosimo Carriere
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Italy
| | - Carlo Vignati
- Centro Cardiologico Monzino, IRCCS, Italy.,Department of Clinical Sciences and Community Health, University of Milano, Italy
| | - Gianfranco Sinagra
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Italy
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Treatment of Cheyne-Stokes respiration with adaptive servoventilation-analysis of patients with regard to therapy restriction. SOMNOLOGIE 2020; 25:226-231. [PMID: 33046962 PMCID: PMC7542574 DOI: 10.1007/s11818-020-00269-2] [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: 06/22/2020] [Accepted: 09/09/2020] [Indexed: 10/27/2022]
Abstract
Purpose The SERVE-HF study revealed no benefit of adaptive servoventilation (ASV) versus guideline-based medical treatment in patients with symptomatic heart failure, an ejection fraction (EF) ≤45% and a predominance of central events (apnoea-hypopnea Index [AHI] > 15/h). Because both all-cause and cardiovascular mortality were higher in the ASV group, an EF ≤ 45% in combination with AHI 15/h, central apnoea-hyponoea index [CAHI/AHI] > 50% and central apnoea index [CAI] > 10/h were subsequently listed as contraindications for ASV. The intention of our study was to analyse the clinical relevance of this limitation. Methods Data were analysed retrospectively for patients treated with ASV who received follow-up echocardiography to identify contraindications for ASV. Results Echocardiography was conducted in 23 patients. The echocardiogram was normal in 10 cases, a left ventricular hypertrophy with normal EF was found in 8 patients, there was an EF 45-50% in 2 cases and a valvular aortic stenosis (grade II) with normal EF was found in 1 case. EF <45% was present in just 2 cases, and only 1 of these patients also had more than 50% central events in the diagnostic night. Conclusion The population typically treated with ASV is entirely different from the study population in SERVE-HF, as nearly half of the patients treated with ASV showed a normal echocardiogram. Thus, the modified indication for ASV has little impact on the majority of treated patients. The current pathomechanistic hypothesis of central apnoea must be reviewed.
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Agostoni P, Salvioni E. Exertional Periodic Breathing in Heart Failure: Mechanisms and Clinical Implications. Clin Chest Med 2020; 40:449-457. [PMID: 31078221 DOI: 10.1016/j.ccm.2019.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Periodic breathing (PB) during exercise is a slow, prominent, consistent fluctuation in ventilation and derived parameters that may be persistent for the entire exercise or present only in the early phases of exercise. It is associated with a negative prognosis, particularly if concomitant with PB during sleep. Little is known about exercise-induced PB physiology, but hyperventilation is likely due to an increased sympathetic activity combined with an enhanced stimulation of intrapulmonary, chemoreceptors and metaboreceptors, low cardiac output leading to increased circulatory delay, and cerebrovascular reactivity to CO2, all with have a definite role.
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Affiliation(s)
- Piergiuseppe Agostoni
- Department of Clinical Sciences and Community Health, Cardiovascular Section, University of Milano, Via Parea 4, Milano 20138, Italy; Centro Cardiologico Monzino, IRCCS, Via Parea 4, Milano 20138, Italy.
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Herkenrath S, Randerath W. Zentrale Schlafapnoe bei Chiari-Malformation Typ I. SOMNOLOGIE 2020. [DOI: 10.1007/s11818-020-00236-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kahn D, Baele P, Pasquet A, Liistro G. Cheyne-Stokes respiration and cardiovascular oscillations ending abruptly when deploying transfemoral aortic valve. J Appl Physiol (1985) 2020; 128:345-349. [PMID: 31873067 DOI: 10.1152/japplphysiol.00193.2019] [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
A 86-yr-old man was referred for transfemoral aortic valve implantation. Transthoracic echocardiography revealed a severe stenosis (mean gradient: 58 mmHg, aortic valve area: 0.4 cm2), and after multidisciplinary discussion, the risk of surgery was judged too high (logistic Euroscore: 51%), and the patient was proposed for a transfemoral aortic valve implantation (TAVI). On arrival in the operating room, the patient, fully conscious, was noted to have Cheyne-Stokes breathing (CSB), which persisted after 40% oxygen administration. TAVI procedure was successful, and the CSB pattern was interrupted within 8 s. To the best of our knowledge, this report is the first to show an acute disappearance of CSB, occurring only seconds after TAVI and restoration of a normal hemodynamic situation. To explain such rapid changes in breathing pattern, we hypothesize a role played by the acute release of pulmonary hypertension and pulmonary volume overload.NEW & NOTEWORTHY Acute disappearance of Cheyne-Stokes breathing after transfemoral aortic valve implantation suggests a reflex pathway originating from the fall in pulmonary vessels congestion.
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Affiliation(s)
- David Kahn
- Department of Anaesthesiology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Philippe Baele
- Department of Anaesthesiology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Agnès Pasquet
- Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Giuseppe Liistro
- Pôle de Pneumologie, ORL et Dermatologie, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.,Service de Pneumologie, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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Herkenrath SD, Randerath WJ. More than Heart Failure: Central Sleep Apnea and Sleep-Related Hypoventilation. Respiration 2019; 98:95-110. [PMID: 31291632 DOI: 10.1159/000500728] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 05/02/2019] [Indexed: 12/29/2022] Open
Abstract
Central sleep apnea (CSA) comprises a variety of breathing patterns and clinical entities. They can be classified into 2 categories based on the partial pressure of carbon dioxide in the arterial blood. Nonhypercapnic CSA is usually characterized by a periodic breathing pattern, while hypercapnic CSA is based on hypoventilation. The latter CSA form is associated with central nervous, neuromuscular, and rib cage disorders as well as obesity and certain medication or substance intake. In contrast, nonhypercapnic CSA is typically accompanied by an overshoot of the ventilation and often associated with heart failure, cerebrovascular diseases, and stay in high altitude. CSA and hypoventilation syndromes are often considered separately, but pathophysiological aspects frequently overlap. An integrative approach helps to recognize underlying pathophysiological mechanisms and to choose adequate therapeutic strategies. Research in the last decades improved our insights; nevertheless, diagnostic tools are not always appropriately chosen to perform comprehensive sleep studies. This supports misinterpretation and misclassification of sleep disordered breathing. The purpose of this article is to highlight unresolved problems, raise awareness for different pathophysiological components and to discuss the evidence for targeted therapeutic strategies.
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Common Co-Morbidities in Heart Failure – Diabetes, Functional Mitral Regurgitation and Sleep Apnoea. ACTA ACUST UNITED AC 2019; 1:25-41. [PMID: 36262740 PMCID: PMC9536668 DOI: 10.36628/ijhf.2019.0004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 02/06/2023]
Abstract
Heart failure (HF) is a condition that carries a considerable burden of disability many now related to co-existing co-morbidities. The drive to find newer effective therapies targeting novel mechanisms has led to a recent emphasis on treating common co-morbidities that are clustered around contemporary HF patients. Here is renewed contemporary co-morbidities that until recently have received little attention but which are now subject of considerable interest and potential therapeutic advance. These include, diabetes, functional mitral regurgitation and sleep disordered breathing. These three contemporary co-morbidities that have recently been subject to major trial evaluation will be reviewed in this paper.
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Perger E, Inami T, Lyons OD, Alshaer H, Smith S, Floras JS, Logan AG, Arzt M, Duran Cantolla J, Delgado D, Fitzpatrick M, Fleetham J, Kasai T, Kimoff RJ, Leung RS, Lorenzi Filho G, Mayer P, Mielniczuk L, Morrison DL, Parati G, Parthasarathy S, Redolfi S, Ryan CM, Series F, Tomlinson GA, Woo A, Bradley TD. Distinct Patterns of Hyperpnea During Cheyne-Stokes Respiration: Implication for Cardiac Function in Patients With Heart Failure. J Clin Sleep Med 2017; 13:1235-1241. [PMID: 29065956 PMCID: PMC5656472 DOI: 10.5664/jcsm.6788] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 01/06/2023]
Abstract
STUDY OBJECTIVES In heart failure (HF), we observed two patterns of hyperpnea during Cheyne-Stokes respiration with central sleep apnea (CSR-CSA): a positive pattern where end-expiratory lung volume remains at or above functional residual capacity, and a negative pattern where it falls below functional residual capacity. We hypothesized the negative pattern is associated with worse HF. METHODS Patients with HF underwent polysomnography. During CSR-CSA, hyperpnea, apnea-hyperpnea cycle, and lung to finger circulation times (LFCT) were measured. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentration and left ventricular ejection fraction (LVEF) were assessed. RESULTS Of 33 patients with CSR-CSA (31 men, mean age 68 years), 9 had a negative hyperpnea pattern. There was no difference in age, body mass index, and apnea-hypopnea index between groups. Patients with a negative pattern had longer hyperpnea time (39.5 ± 6.4 versus 25.8 ± 5.9 seconds, P < .01), longer cycle time (67.8 ± 15.9 versus 51.7 ± 9.9 seconds, P < .01), higher NT-proBNP concentrations (2740 [6769] versus 570 [864] pg/ml, P = .01), and worse New York Heart Association class (P = .02) than those with a positive pattern. LFCT and LVEF did not differ between groups. CONCLUSIONS Patients with HF and a negative CSR-CSA pattern have evidence of worse cardiac function than those with a positive pattern. Greater positive expiratory pressure during hyperpnea is likely generated during the negative pattern and might support stroke volume in patients with worse cardiac function. COMMENTARY A commentary on this article appears in this issue on page 1227. CLINICAL TRIAL REGISTRATION The trial is registered with Current Controlled Trials (www.controlled-trials.com; ISRCTN67500535) and Clinical Trials (www.clinicaltrials.gov; NCT01128816).
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Affiliation(s)
- Elisa Perger
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, Ontario, Canada
| | - Toru Inami
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, Ontario, Canada
| | - Owen D. Lyons
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, Ontario, Canada
| | - Hisham Alshaer
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Stephanie Smith
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
| | - John S. Floras
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Alexander G. Logan
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Michael Arzt
- Universitätsklinikum Regensburg, Regensburg, Germany
| | | | - Diego Delgado
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
| | | | - John Fleetham
- Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - R. John Kimoff
- McGill University Health Centre, Montreal, Quebec, Canada
| | | | | | - Pierre Mayer
- Hôpital Hôtel-Dieu du CHUM, Université de Montréal, Montreal, Quebec, Canada
| | - Lisa Mielniczuk
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | | | | | | | | | - Clodagh M. Ryan
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, Ontario, Canada
| | - Frederic Series
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Quebec, Canada
| | | | - Anna Woo
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
| | - T. Douglas Bradley
- University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, Ontario, Canada
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O'Donnell DE, Elbehairy AF, Berton DC, Domnik NJ, Neder JA. Advances in the Evaluation of Respiratory Pathophysiology during Exercise in Chronic Lung Diseases. Front Physiol 2017; 8:82. [PMID: 28275353 PMCID: PMC5319975 DOI: 10.3389/fphys.2017.00082] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/30/2017] [Indexed: 11/13/2022] Open
Abstract
Dyspnea and exercise limitation are among the most common symptoms experienced by patients with various chronic lung diseases and are linked to poor quality of life. Our understanding of the source and nature of perceived respiratory discomfort and exercise intolerance in chronic lung diseases has increased substantially in recent years. These new mechanistic insights are the primary focus of the current review. Cardiopulmonary exercise testing (CPET) provides a unique opportunity to objectively evaluate the ability of the respiratory system to respond to imposed incremental physiological stress. In addition to measuring aerobic capacity and quantifying an individual's cardiac and ventilatory reserves, we have expanded the role of CPET to include evaluation of symptom intensity, together with a simple "non-invasive" assessment of relevant ventilatory control parameters and dynamic respiratory mechanics during standardized incremental tests to tolerance. This review explores the application of the new advances in the clinical evaluation of the pathophysiology of exercise intolerance in chronic obstructive pulmonary disease (COPD), chronic asthma, interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH). We hope to demonstrate how this novel approach to CPET interpretation, which includes a quantification of activity-related dyspnea and evaluation of its underlying mechanisms, enhances our ability to meaningfully intervene to improve quality of life in these pathologically-distinct conditions.
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Affiliation(s)
- Denis E. O'Donnell
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
| | - Amany F. Elbehairy
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
- Department of Chest Diseases, Faculty of Medicine, Alexandria UniversityAlexandria, Egypt
| | - Danilo C. Berton
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
| | - Nicolle J. Domnik
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
| | - J. Alberto Neder
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
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Pathophysiology of central sleep apneas. Sleep Breath 2016; 20:467-82. [DOI: 10.1007/s11325-015-1290-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 11/10/2015] [Accepted: 11/23/2015] [Indexed: 11/26/2022]
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16
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Lyons OD, Chan CT, Yadollahi A, Bradley TD. Effect of ultrafiltration on sleep apnea and sleep structure in patients with end-stage renal disease. Am J Respir Crit Care Med 2015; 191:1287-94. [PMID: 25822211 DOI: 10.1164/rccm.201412-2288oc] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
RATIONALE In end-stage renal disease (ESRD), a condition characterized by fluid overload, both obstructive and central sleep apnea (OSA and CSA) are common. This observation suggests that fluid overload is involved in the pathogenesis of OSA and CSA in this condition. OBJECTIVES To test the hypothesis that fluid removal by ultrafiltration (UF) will reduce severity of OSA and CSA in patients with ESRD. METHODS At baseline, on a nondialysis day, patients with ESRD on thrice-weekly hemodialysis underwent overnight polysomnography along with measurement of total body extracellular fluid volume (ECFV), and ECFV of the neck, thorax, and right leg before and after sleep. The following week, on a nondialysis day, subjects with an apnea-hypopnea index (AHI) greater than or equal to 20 had fluid removed by UF, followed by repeat overnight polysomnography with fluid measurements. MEASUREMENTS AND MAIN RESULTS Fifteen patients (10 men) with an AHI greater than or equal to 20 (10 OSA; 5 CSA) participated. Mean age was 53.5 ± 10.4 years and mean body mass index was 25.3 ± 4.8 kg/m(2). Following removal of 2.17 ± 0.45 L by UF, the AHI decreased by 36% (43.8 ± 20.3 to 28.0 ± 17.7; P < 0.001) without affecting uremia. The reduction in AHI correlated with the reduction in total body ECFV (r = 0.567; P = 0.027) and was associated with reductions in ECFV of the right leg (P = 0.001), overnight change in ECFV of the right leg (P = 0.044), ECFV of the thorax (P = 0.001), and ECFV of the neck (P = 0.003). CONCLUSIONS These findings indicate that fluid overload contributes to the pathogenesis of OSA and CSA in ESRD, and that fluid removal by UF attenuates sleep apnea without altering uremic status.
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Affiliation(s)
- Owen D Lyons
- 1 Sleep Research Laboratory, University Health Network Toronto Rehabilitation Institute, Toronto, Canada
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Costanzo MR, Khayat R, Ponikowski P, Augostini R, Stellbrink C, Mianulli M, Abraham WT. Mechanisms and clinical consequences of untreated central sleep apnea in heart failure. J Am Coll Cardiol 2015; 65:72-84. [PMID: 25572513 PMCID: PMC4391015 DOI: 10.1016/j.jacc.2014.10.025] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 09/22/2014] [Accepted: 10/15/2014] [Indexed: 01/08/2023]
Abstract
Central sleep apnea (CSA) is a highly prevalent, though often unrecognized, comorbidity in patients with heart failure (HF). Data from HF population studies suggest that it may present in 30% to 50% of HF patients. CSA is recognized as an important contributor to the progression of HF and to HF-related morbidity and mortality. Over the past 2 decades, an expanding body of research has begun to shed light on the pathophysiologic mechanisms of CSA. Armed with this growing knowledge base, the sleep, respiratory, and cardiovascular research communities have been working to identify ways to treat CSA in HF with the ultimate goal of improving patient quality of life and clinical outcomes. In this paper, we examine the current state of knowledge about the mechanisms of CSA in HF and review emerging therapies for this disorder.
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Affiliation(s)
| | - Rami Khayat
- Division of Pulmonary, Critical Care and Sleep, The Ohio State University, Columbus, Ohio
| | - Piotr Ponikowski
- Cardiac Department, 4th Military Hospital, Wroclaw, Poland; Cardiac Department, Medical University, Wroclaw, Poland
| | - Ralph Augostini
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio
| | - Christoph Stellbrink
- Department of Cardiology and Intensive Care Medicine, Bielefeld Medical Center, Bielefeld, Germany
| | | | - William T Abraham
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio
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Holbein WW, Toney GM. Activation of the hypothalamic paraventricular nucleus by forebrain hypertonicity selectively increases tonic vasomotor sympathetic nerve activity. Am J Physiol Regul Integr Comp Physiol 2014; 308:R351-9. [PMID: 25519737 DOI: 10.1152/ajpregu.00460.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We recently reported that mean arterial pressure (MAP) is maintained in water-deprived rats by an irregular tonic component of vasomotor sympathetic nerve activity (SNA) that is driven by neuronal activity in the hypothalamic paraventricular nucleus (PVN). To establish whether generation of tonic SNA requires time-dependent (i.e., hours or days of dehydration) neuroadaptive responses or can be abruptly generated by even acute circuit activation, forebrain sympathoexcitatory osmosensory inputs to PVN were stimulated by infusion (0.1 ml/min, 10 min) of hypertonic saline (HTS; 1.5 M NaCl) through an internal carotid artery (ICA). Whereas isotonic saline (ITS; 0.15 M NaCl) had no effect (n = 5), HTS increased (P < 0.001; n = 6) splanchnic SNA (sSNA), phrenic nerve activity (PNA), and MAP. Bilateral PVN injections of muscimol (n = 6) prevented HTS-evoked increases of integrated sSNA and PNA (P < 0.001) and attenuated the accompanying pressor response (P < 0.01). Blockade of PVN NMDA receptors with d-(2R)-amino-5-phosphonovaleric acid (AP5; n = 6) had similar effects. Analysis of respiratory rhythmic bursting of sSNA revealed that ICA HTS increased mean voltage (P < 0.001) without affecting the amplitude of inspiratory or expiratory bursts. Analysis of cardiac rhythmic sSNA likewise revealed that ICA HTS increased mean voltage. Cardiac rhythmic sSNA oscillation amplitude was also increased, which is consistent with activation of arterial baroreceptor during the accompanying pressor response. Increased mean sSNA voltage by HTS was blocked by prior PVN inhibition (muscimol) and blockade of PVN NMDA receptors (AP5). We conclude that even acute glutamatergic activation of PVN (i.e., by hypertonicity) is sufficient to selectively increase a tonic component of vasomotor SNA.
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Affiliation(s)
| | - Glenn M Toney
- Department of Physiology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas
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Ohmura T, Iwama Y, Kasai T, Kato T, Suda S, Takagi A, Daida H. Impact of predischarge nocturnal pulse oximetry (sleep-disordered breathing) on postdischarge clinical outcomes in hospitalized patients with left ventricular systolic dysfunction after acute decompensated heart failure. Am J Cardiol 2014; 113:697-700. [PMID: 24342759 DOI: 10.1016/j.amjcard.2013.10.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/23/2013] [Accepted: 10/23/2013] [Indexed: 01/06/2023]
Abstract
Stratifying patients at a high risk for readmission and mortality before their discharge after acute decompensated heart failure (ADHF) is important. Although sleep-disordered breathing (SDB) is prevalent in patients with chronic heart failure, only few studies have investigated the impact of SDB on hospitalized patients with left ventricular (LV) systolic dysfunction after ADHF. Thus, we assessed the prevalence of SDB using nocturnal pulse oximetry and the relation between SDB and clinical events in this patient group. One hundred consecutive patients with LV systolic dysfunction who were hospitalized for ADHF were enrolled in the study. Predischarge nocturnal oximetry was performed to determine if they had SDB (defined as an oxygen desaturation index of ≥5 events/hour with ≥4% decrease in saturation level). Data on death and readmission for ADHF were collected. Forty-one patients had SDB. Complete outcome data were collected in the mean follow-up period of 14.2 months during which 33 events occurred. On multivariate Cox proportional hazards regression analysis, the presence of SDB was a significant independent predictor of postdischarge readmission and mortality (hazard ratio 2.93, p = 0.006). In conclusion, SDB, as determined by predischarge nocturnal oximetry, is prevalent and is an independent predictor of the combined end point of readmission and mortality in hospitalized patients with LV systolic dysfunction after ADHF.
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Affiliation(s)
- Takayasu Ohmura
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan; Nihonbashi Cardiology Clinic, Tokyo, Japan
| | - Yoshitaka Iwama
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan; Nihonbashi Cardiology Clinic, Tokyo, Japan
| | - Takatoshi Kasai
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan; Cardio-Respiratory Sleep Medicine, Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan.
| | - Takao Kato
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Shoko Suda
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan; Cardio-Respiratory Sleep Medicine, Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Atsutoshi Takagi
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hiroyuki Daida
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan
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Khayat R, Small R, Rathman L, Krueger S, Gocke B, Clark L, Yamokoski L, Abraham WT. Sleep-disordered breathing in heart failure: identifying and treating an important but often unrecognized comorbidity in heart failure patients. J Card Fail 2013; 19:431-44. [PMID: 23743494 DOI: 10.1016/j.cardfail.2013.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/09/2013] [Accepted: 04/18/2013] [Indexed: 01/29/2023]
Abstract
Sleep-disordered breathing (SDB) is the most common comorbidity in patients with heart failure (HF) and has a significant impact on quality of life, morbidity, and mortality. A number of therapeutic options have become available in recent years that can improve quality of life and potentially the outcomes of HF patients with SDB. Unfortunately, SDB is not part of the routine evaluation and management of HF, so it remains untreated in most HF patients. Although recognition of the role of SDB in HF is increasing, clinical guidelines for the management of SDB in HF patients continue to be absent. This article provides an overview of SDB in HF and proposes a clinical care pathway to help clinicians to better recognize and treat SDB in their HF patients.
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Affiliation(s)
- Rami Khayat
- Ohio State University, Division of Pulmonary, Critical Care and Sleep, Columbus, OH 43210, USA.
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21
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Bradley TD, Kasai T. Reply. J Am Coll Cardiol 2013; 62:1037-8. [PMID: 23643499 DOI: 10.1016/j.jacc.2013.04.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 04/23/2013] [Indexed: 10/26/2022]
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Plataki M, Sands SA, Malhotra A. Clinical consequences of altered chemoreflex control. Respir Physiol Neurobiol 2013; 189:354-63. [PMID: 23681082 DOI: 10.1016/j.resp.2013.04.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 04/19/2013] [Accepted: 04/25/2013] [Indexed: 01/28/2023]
Abstract
Control of ventilation dictates various breathing patterns. The respiratory control system consists of a central pattern generator and several feedback mechanisms that act to maintain ventilation at optimal levels. The concept of loop gain has been employed to describe its stability and variability. Synthesizing all interactions under a general model that could account for every behavior has been challenging. Recent insight into the importance of these feedback systems may unveil therapeutic strategies for common ventilatory disturbances. In this review we will address the major mechanisms that have been proposed as mediators of some of the breathing patterns in health and disease that have raised controversies and discussion on ventilatory control over the years.
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Affiliation(s)
- Maria Plataki
- Department of Internal Medicine, Bridgeport Hospital, Yale New Haven Health, Bridgeport, CT, USA
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White LH, Bradley TD. Role of nocturnal rostral fluid shift in the pathogenesis of obstructive and central sleep apnoea. J Physiol 2013; 591:1179-93. [PMID: 23230237 PMCID: PMC3607865 DOI: 10.1113/jphysiol.2012.245159] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 12/06/2012] [Indexed: 12/25/2022] Open
Abstract
Obstructive sleep apnoea (OSA) is common in the general population and increases the risk of motor vehicle accidents due to hypersomnolence from sleep disruption, and risk of cardiovascular diseases owing to repetitive hypoxia, sympathetic nervous system activation, and systemic inflammation. In contrast, central sleep apnoea (CSA) is rare in the general population. Although their pathogenesis is multifactorial, the prevalence of both OSA and CSA is increased in patients with fluid retaining states, especially heart failure, where they are associated with increased mortality risk. This observation suggests that fluid retention may contribute to the pathogenesis of both OSA and CSA. According to this hypothesis, during the day fluid accumulates in the intravascular and interstitial spaces of the legs due to gravity, and upon lying down at night redistributes rostrally, again owing to gravity. Some of this fluid may accumulate in the neck, increasing tissue pressure and causing the upper airway to narrow, thereby increasing its collapsibility and predisposing to OSA. In heart failure patients, with increased rostral fluid shift, fluid may additionally accumulate in the lungs, provoking hyperventilation and hypocapnia, driving below the apnoea threshold, leading to CSA. This review article will explore mechanisms by which overnight rostral fluid shift, and its prevention, can contribute to the pathogenesis and therapy of sleep apnoea.
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Affiliation(s)
- Laura H White
- Department of Medicine, University Health Network Toronto General Hospital, Rehabilitation Institute, University of Toronto, Ontario, Canada
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Kasai T, Motwani SS, Yumino D, Gabriel JM, Montemurro LT, Amirthalingam V, Floras JS, Bradley TD. Contrasting effects of lower body positive pressure on upper airways resistance and partial pressure of carbon dioxide in men with heart failure and obstructive or central sleep apnea. J Am Coll Cardiol 2013; 61:1157-66. [PMID: 23375931 DOI: 10.1016/j.jacc.2012.10.055] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/23/2012] [Accepted: 10/28/2012] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This study sought to test the effects of rostral fluid displacement from the legs on transpharyngeal resistance (Rph), minute volume of ventilation (Vmin), and partial pressure of carbon dioxide (PCO2) in men with heart failure (HF) and either obstructive (OSA) or central sleep apnea (CSA). BACKGROUND Overnight rostral fluid shift relates to severity of OSA and CSA in men with HF. Rostral fluid displacement may facilitate OSA if it shifts into the neck and increases Rph, because pharyngeal obstruction causes OSA. Rostral fluid displacement may also facilitate CSA if it shifts into the lungs and induces reflex augmentation of ventilation and reduces PCO2, because a decrease in PCO2 below the apnea threshold causes CSA. METHODS Men with HF were divided into those with mainly OSA (obstructive-dominant, n = 18) and those with mainly CSA (central-dominant, n = 10). While patients were supine, antishock trousers were deflated (control) or inflated for 15 min (lower body positive pressure [LBPP]) in random order. RESULTS LBPP reduced leg fluid volume and increased neck circumference in both obstructive- and central-dominant groups. However, in contrast to the obstructive-dominant group in whom LBPP induced an increase in Rph, a decrease in Vmin, and an increase in PCO2, in the central-dominant group, LBPP induced a reduction in Rph, an increase in Vmin, and a reduction in PCO2. CONCLUSIONS These findings suggest mechanisms by which rostral fluid shift contributes to the pathogenesis of OSA and CSA in men with HF. Rostral fluid shift could facilitate OSA if it induces pharyngeal obstruction, but could also facilitate CSA if it augments ventilation and lowers PCO2.
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Affiliation(s)
- Takatoshi Kasai
- Sleep Research Laboratory of the Toronto Rehabilitation Institute, University of Toronto, Toronto, Ontario, Canada
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25
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Sekizuka H, Osada N, Miyake F. Sleep disordered breathing in heart failure patients with reduced versus preserved ejection fraction. Heart Lung Circ 2012; 22:104-9. [PMID: 23107286 DOI: 10.1016/j.hlc.2012.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 08/01/2012] [Accepted: 08/03/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND This study aimed to investigate and compare prevalence of sleep disordered breathing (SDB) in Japanese patients with heart failure with reduced ejection fraction (HFrEF) versus those with HF with preserved EF (HFpEF). METHODS This study consecutively included 101 Japanese patients (77 males) with de novo CHF. Echocardiography was performed twice, on admission and at discharge. All patients underwent portable overnight polygraphy within one week before discharge. The patients were stratified into two groups based on LVEF on admission, HFrEF (R group; LVEF<50%, n=82) or HFpEF (P group; LVEF≧50%, n=19); the prevalence of SDB and sleep study data were assessed. RESULTS When patients with the apnea hypopnea index ≥15 were defined as having SDB, 50% of the study patients had SDB (OSA, 10%; CSA, 39%; MSA, 1%). No significant differences in the prevalence of SDB or sleep data as well as RVSP, E/e' or plasma brain natriuretic peptide (BNP) were found between the two groups. CONCLUSIONS SDB was identified in 50% of de novo Japanese HF patients. When E/e', RVSP and plasma BNP did not significantly differ between the two groups, the prevalence of SDB was similar regardless of LVEF.
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Affiliation(s)
- Hiromitsu Sekizuka
- Division of Cardiology, Department of Internal Medicine, St. Marianna University School of Medicine, Japan.
| | - Naohiko Osada
- Division of Cardiology, Department of Internal Medicine, St. Marianna University School of Medicine, Japan
| | - Fumihiko Miyake
- Division of Cardiology, Department of Internal Medicine, St. Marianna University School of Medicine, Japan
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Bitter T, Körber B, Horstkotte D, Oldenburg O. [Sleep-disordered breathing and cardiac arrhythmias]. Herzschrittmacherther Elektrophysiol 2012; 23:22-6. [PMID: 22351149 DOI: 10.1007/s00399-011-0164-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Sleep-disordered breathing (SDB) is an important comorbidity in patients with cardiac arrhythmias. Previous studies confirmed associations between supraventricular and ventricular arrhythmias and SDB. In heart failure patients, SDB was also found independently associated with a shorter event-free survival to the occurrence of malignant ventricular arrhythmias requiring appropriate cardioverter-defibrillator therapy. In obstructive sleep apnea, repetitive hypoxemia, mechanical stress (wall tension), arousals from sleep, and activation of the sympathetic nervous system promote cardiac arrhythmias. Pathophysiological concepts for the link between Cheyne-Stokes respiration and malignant arrhythmias are not fully understood and require further research. In addition, large-scale, randomized, controlled trials are awaited to prove whether adequate treatment of SDB is associated with a risk reduction for the occurrence of arrhythmias, in general, and malignant ventricular arrhythmias, in particular, in these patients.
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Affiliation(s)
- T Bitter
- Klinik für Kardiologie, Herz- und Diabeteszentrum Nordrhein-Westfalen, Ruhr-Universität Bochum, Georgstr. 11, 32545, Bad Oeynhausen, Deutschland.
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Song N, Roberts AM, Yu J. Hypertonicity activates pulmonary vagal afferents independently of vasoconstriction. Respir Physiol Neurobiol 2011; 179:338-41. [PMID: 21983524 DOI: 10.1016/j.resp.2011.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 09/25/2011] [Accepted: 09/26/2011] [Indexed: 10/17/2022]
Abstract
Injecting hypertonic saline into the lung periphery causes a vagally mediated neural hyperpnea and tachypnea (the excitatory lung reflex, ELR). In the present study, we tested the hypothesis that hypertonic saline activates lung afferents mainly by increasing fluid flux from pulmonary vessels into the alveoli. If our hypothesis is correct, reducing perfusion of the vagal sensory region will reduce the fluid flux and attenuate the ELR. In anesthetized, open chest and mechanically ventilated rabbits, using intravital video microscopy, we confirmed that topical KCl (100 mM) constricted sub-pleural blood vessels and limited blood flow significantly, as indicated by a 43.3±9% decrease in arteriolar diameters (p<0.005), sluggish microvascular flow and paleness of alveolar walls. Then, we compared respiratory responses (assessed from phrenic nerve activity) to injections of hypertonic saline (8.1%, 0.1 ml) into the lung periphery before and after locally injecting KCl to limit fluid flux. The respiratory responses were the same with or without vasoconstriction. However, the responses were significantly decreased (from 22±5% to 1±2% for phrenic amplitude and from 75±9% to 13±6% for phrenic burst rate; n=14, p<0.02) after local injection of 2% lidocaine to block sensory endings. Since the ELR was not attenuated by vasoconstriction, increased transvascular fluid flux does not appear to be a major mechanism for hypertonic saline induced ELR.
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Affiliation(s)
- N Song
- Departments of Medicine, University of Louisville, Louisville, KY 40292, United States
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28
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Abstract
About half of the patients suffering from heart failure present with sleep-disordered breathing. In most cases obstructive and central breathing disturbances (including Cheyne-Stokes respiration [CSR]) coexist. CSR is defined by a waxing and waning pattern of the tidal volume. While its pathophysiology has not been elucidated completely, increased ventilatory sensitivity for CO2 and therefore an imbalance of the respiratory drive and effort, a chronic hyperventilatory state, and changes of the apnoeic threshold are considered to play a relevant role. However, CSR in heart failure impairs survival and quality of life of the patients and is therefore a major challenge of respiratory sleep medicine. If CSR persists despite optimal medical and interventional therapy of the underlying cardiac disorder, oxygen supply, continuous positive airway pressure (CPAP), and bilevel pressure are often trialled. However, there is insufficient evidence to recommend oxygen or bilevel treatment. CPAP has proven to improve left ventricular function. In addition, retrospective analyses suggested a reduction of mortality under CPAP in heart failure patients with CSR. However, these findings could not be reproduced in the prospective controlled CanPAP trial. More recently, adaptive servoventilation (ASV) has been introduced for treatment of CSR or coexisting sleep-related breathing disorders. ASV devices aim at counterbalancing the ventilatory overshoot and undershoot by applying variable pressure support with higher tidal volume (TV) during hypoventilation and reduced TV during hyperventilation. ASV has proven to be superior to CPAP but the long-term efficacy and the influences on cardiac parameters and survival are still under investigation.
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Affiliation(s)
- Winfried J. Randerath
- Institute of Pneumology at the University Witten/Herdecke, Clinic for Pneumology and Allergology, Center of Sleep Medicine and Respiratory Care, Bethanien Hospital, Aufderhöherstraße 169-175, 42699 Solingen, Germany,
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Yumino D, Redolfi S, Ruttanaumpawan P, Su MC, Smith S, Newton GE, Mak S, Bradley TD. Nocturnal rostral fluid shift: a unifying concept for the pathogenesis of obstructive and central sleep apnea in men with heart failure. Circulation 2010; 121:1598-605. [PMID: 20351237 DOI: 10.1161/circulationaha.109.902452] [Citation(s) in RCA: 322] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Obstructive sleep apnea (OSA) and central sleep apnea are common in patients with heart failure. We hypothesized that in such patients, severity of OSA is related to overnight rostral leg fluid displacement and increase in neck circumference, severity of central sleep apnea is related to overnight rostral fluid displacement and to sleep Pco(2), and continuous positive airway pressure alleviates OSA in association with prevention of fluid accumulation in the neck. METHODS AND RESULTS In 57 patients with heart failure (ejection fraction <or=45%), we measured change in leg fluid volume and neck circumference before and after polysomnography, and we measured transcutaneous Pco(2) during polysomnography. Patients were divided into an obstructive-dominant group (>or=50% of apneas and hypopneas obstructive) and a central-dominant group (>50% of events central). Patients with OSA received continuous positive airway pressure. In obstructive-dominant patients, there were inverse relationships between overnight change in leg fluid volume and both the overnight change in neck circumference (r=-0.780, P<0.001) and the apnea-hypopnea index (r=-0.881, P<0.001) but not transcutaneous Pco(2). In central-dominant patients, the overnight reduction in leg fluid volume correlated inversely with the apnea-hypopnea index (r=-0.919, P<0.001) and the overnight change in neck circumference (r=-0.568, P=0.013) and directly with transcutaneous Pco(2) (r=0.569, P=0.009). Continuous positive airway pressure alleviated OSA in association with prevention of the overnight increase in neck circumference (P<0.001). CONCLUSIONS Our findings suggest that nocturnal rostral fluid shift is a unifying concept contributing to the pathogenesis of both OSA and central sleep apnea in patients with heart failure.
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Affiliation(s)
- Dai Yumino
- Toronto General Hospital/University Health Network, 9N-943, 200 Elizabeth St, Toronto, Ontario M5G 2C4, Canada
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Impact of sleeping position on central sleep apnea/Cheyne–Stokes respiration in patients with heart failure. Sleep Med 2010; 11:143-8. [DOI: 10.1016/j.sleep.2009.05.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 05/18/2009] [Accepted: 05/24/2009] [Indexed: 11/22/2022]
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Therapie der Cheyne-Stokes-Atmung bei Herzinsuffizienz. SOMNOLOGIE 2009. [DOI: 10.1007/s11818-009-0443-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Sleep apnoea in patients with heart failure. Part I: Diagnosis, definitions, prevalence, pathophysiology and haemodynamic consequences. Arch Cardiovasc Dis 2009; 102:651-61. [DOI: 10.1016/j.acvd.2009.05.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 05/06/2009] [Accepted: 05/11/2009] [Indexed: 11/16/2022]
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Bitter T, Faber L, Hering D, Langer C, Horstkotte D, Oldenburg O. Sleep-disordered breathing in heart failure with normal left ventricular ejection fraction. Eur J Heart Fail 2009; 11:602-8. [PMID: 19468022 DOI: 10.1093/eurjhf/hfp057] [Citation(s) in RCA: 197] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Thomas Bitter
- Department of Cardiology, Heart and Diabetes Center North Rhine-Westphalia; Ruhr University Bochum; Georgstasse 11 D-32545 Bad Oeynhausen Germany
| | - Lothar Faber
- Department of Cardiology, Heart and Diabetes Center North Rhine-Westphalia; Ruhr University Bochum; Georgstasse 11 D-32545 Bad Oeynhausen Germany
| | - Detlef Hering
- Department of Cardiology, Heart and Diabetes Center North Rhine-Westphalia; Ruhr University Bochum; Georgstasse 11 D-32545 Bad Oeynhausen Germany
| | - Christoph Langer
- Department of Cardiology, Heart and Diabetes Center North Rhine-Westphalia; Ruhr University Bochum; Georgstasse 11 D-32545 Bad Oeynhausen Germany
| | - Dieter Horstkotte
- Department of Cardiology, Heart and Diabetes Center North Rhine-Westphalia; Ruhr University Bochum; Georgstasse 11 D-32545 Bad Oeynhausen Germany
| | - Olaf Oldenburg
- Department of Cardiology, Heart and Diabetes Center North Rhine-Westphalia; Ruhr University Bochum; Georgstasse 11 D-32545 Bad Oeynhausen Germany
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Abstract
In septic patients increased central drive and increased metabolic demands combine to increase energy demands on the ventilatory muscles. This occurs at a time when energy supplies are limited and energy production hindered, and it leads to an energy supply-demand imbalance and often ventilatory failure. Problems related to contractile function of the ventilatory muscles also contribute, especially when the clinical course is prolonged. The increased ventilatory activity increases interactions between the ventilatory and cardiovascular systems, and when ventilatory muscles fail and mechanical ventilatory support is required a new set of problems emerges. In this review I discuss factors related to ventilatory muscle failure, giving emphasis to mechanical and supply demand aspects. I also review the implications of changes in ventilatory patterns for heart-lung interactions.
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Affiliation(s)
- Sheldon Magder
- Department of Medicine, Division of Critical Care, McGill University Health Centre, Montreal, Quebec, Canada.
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35
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Saitoh Y, Oshima T, Nakata Y. Monitoring of vecuronium-induced neuromuscular blockade during one-lung ventilation. J Anesth 2008; 22:378-84. [PMID: 19011776 DOI: 10.1007/s00540-008-0666-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 07/09/2008] [Indexed: 11/29/2022]
Abstract
PURPOSE We investigated the monitoring of neuromuscular blockade caused by vecuronium in patients receiving one-lung ventilation (OLV) anesthesia for lung surgery. METHODS Eighteen adult patients requiring OLV for lung surgery (OLV group) and 18 undergoing two-lung ventilation (TLV) for colon surgery (control group) were enrolled in this study. In the two groups, anesthesia was maintained with sevoflurane, fentanyl, and epidural lidocaine. Time from vecuronium 0.1 mg.kg(-1) to the onset of neuromuscular blockade; times to the return of T1, T2, T3, or T4 (the first, second, third, or fourth response of the train-of-four [TOF]); and recovery of T1/control or TOF ratio (T4/T1) were compared between the two groups. RESULTS Time to the onset of neuromuscular blockade in the OLV group was similar to that in the control group (289 +/- 74 vs 270 +/- 85 s [mean +/- SD]; P = 0.482). Times from vecuronium to the return of T1, T2, T3, or T4 in the OLV group did not significantly differ from those in the control group (21.9 +/- 7.0 vs 25.8 +/- 6.7 min for T1; P = 0.099). T1/control in the OLV group was significantly higher than that in the control group 50-120 min after vecuronium (P < 0.05). The TOF ratio did not differ significantly between the two groups. CONCLUSION During OLV for lung surgery, recovery of T1/control is accelerated in anesthetized patients receiving vecuronium.
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Affiliation(s)
- Yuhji Saitoh
- Department of Anesthesiology, Satte General Hospital, 4-14-24 Higashi, Satte, Saitama, 340-0114, Japan
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Garcia-Touchard A, Somers VK, Olson LJ, Caples SM. Central sleep apnea: implications for congestive heart failure. Chest 2008; 133:1495-1504. [PMID: 18574295 DOI: 10.1378/chest.07-0871] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Congestive heart failure (HF), an exceedingly common and costly disease, is frequently seen in association with central sleep apnea (CSA), which often manifests as a periodic breathing rhythm referred to as Cheyne-Stokes respiration. CSA has historically been considered to be a marker of heart disease, since improvement in cardiac status is often associated with the attenuation of CSA. However, this mirroring of HF and CSA may suggest bidirectional importance to their relationship. In fact, observational data suggest that CSA, associated with repetitive oxyhemoglobin desaturations and surges in sympathetic neural activity, may be of pathophysiologic significance in HF outcomes. In light of the disappointing results from the first large trial assessing therapy with continuous positive airway pressure in patients with CSA and HF, further large-scale interventional trials will be needed to assess the role, if any, of CSA treatment on the outcomes of patients with HF. This review will discuss epidemiologic, pathophysiologic, diagnostic, and therapeutic considerations of CSA in the setting of HF.
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Affiliation(s)
| | - Virend K Somers
- Divisions of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
| | - Lyle J Olson
- Divisions of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
| | - Sean M Caples
- Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN.
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Terán Santos J, Alonso Alvarez ML, Cordero Guevara J, Ayuela Azcárate JM, Monserrat Canal JM. [Sleep apnea-hypopnea syndrome and the heart]. Rev Esp Cardiol 2006; 59:718-24. [PMID: 16938214 DOI: 10.1157/13091373] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cardiovascular and cerebrovascular diseases are the most common diseases in industrialized societies. The main objectives of this article were to summarize the physiological effects of sleep apnea on the circulatory system and to review how treatment of this condition influences cardiovascular disease. Acute sleep apnea has a number of hemodynamic consequences, such as pulmonary and systemic hypertension, increased ventricular afterload and reduced cardiac output, all of which result from sympathetic stimulation, arousal, alterations in intrathoracic pressure, hypoxia and hypercapnia. When chronic, sleep apnea-hypopnea syndrome is associated with systemic hypertension, ischemic heart disease, congestive heart failure, and Cheyne-Stokes respiration in patients with congestive heart failure. Nocturnal treatment with continuous positive airway pressure decreases both the number of central apneic episodes and blood pressure in patients with sleep apnea-hypopnea syndrome and arterial hypertension.
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Lavorini F, Pantaleo T, Geri P, Mutolo D, Pistolesi M, Fontana GA. Cough and ventilatory adjustments evoked by aerosolised capsaicin and distilled water (fog) in man. Respir Physiol Neurobiol 2006; 156:331-9. [PMID: 17134944 DOI: 10.1016/j.resp.2006.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 09/29/2006] [Accepted: 10/23/2006] [Indexed: 12/01/2022]
Abstract
Airway receptors mediate cough and ventilatory adjustments. Simultaneous assessment of cough sensory-motor components and changes in breathing pattern may provide insights into the receptor(s) prevailingly stimulated by inhaled irritants. Nineteen subjects inhaled capsaicin and fog up to threshold concentrations for cough. Cough intensity, respiratory sensations and changes in breathing pattern induced by the two irritants were compared. Capsaicin and fog cough threshold values did not correlate. Coughing induced by both agents was preceded by qualitatively similar sensations and by significant increases in minute ventilation and respiratory drive due to selective increases in tidal volume (P<0.01). Cough intensity was similar with both agents. Cough frequency and the intensity of the urge to cough were higher with capsaicin (P<0.01). The lack of correlation between fog and capsaicin cough threshold values suggests differences in the neural mechanisms activated. The selective increase in tidal volume suggests prevailing involvement of rapidly adapting receptors. The stronger sensations evoked by capsaicin may contribute to the higher cough frequency observed with this agent.
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Affiliation(s)
- Federico Lavorini
- Dipartimento di Area Critica Medico Chirurgica, Unità Funzionale di Medicina Respiratoria, Università di Firenze, Viale G.B. Morgagni 85, 50134 Firenze, Italy
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Fontana GA, Lavorini F. Cough motor mechanisms. Respir Physiol Neurobiol 2006; 152:266-81. [PMID: 16600697 DOI: 10.1016/j.resp.2006.02.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Revised: 02/21/2006] [Accepted: 02/23/2006] [Indexed: 11/29/2022]
Abstract
Cough is a defensive airway mechanisms which involves the sequential activation of several laryngeal and respiratory muscles in the generation of the typical four-phase motor pattern. Activation of such muscles can be considered to represent the "primary" cough motor mechanism, and its functional significance, although complex, appears to be fairly well established. Nonetheless, the outflows of cough are numerous, and may additionally involve the reflex or mechanical activation of other respiratory and non-respiratory motor systems. These additional, or "secondary", outflows of cough can mainly be regarded as being involved in either enhancing the defensive function of cough, or opposing the possible noxious effects exerted by the mechanical stresses of coughing. In addition, both the primary and secondary cough motor mechanisms are known to play multiple functional roles, thus considerably complicating the cough panorama. Finally, some of the secondary cough motor responses, such as the changes in the pattern of breathing, seem to be devoid of any favourable action and their functional meaning, if any, is not fully understood. Although it is well known that all patterns of cough can be produced voluntarily, the extent to which also volitional cough is accompanied by an array of motor responses similar to that of reflex cough remains to be elucidated.
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Affiliation(s)
- Giovanni A Fontana
- Dipartimento di Area Critica Medico Chirurgica, Unità Funzionale di Medicina Respiratoria, Viale G.B. Morgagni 85, 50134 Firenze, Italy.
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Soukhova-O'Hare GK, Zhang JW, Gozal D, Yu J. Bradykinin B2 receptors mediate pulmonary sympathetic afferents induced reflexes in rabbits. Life Sci 2006; 78:1990-7. [PMID: 16289619 DOI: 10.1016/j.lfs.2005.08.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Accepted: 08/31/2005] [Indexed: 11/20/2022]
Abstract
Endogenous bradykinin (BK) is an established mediator of pulmonary inflammation, yet its role in lung disease is unclear. In the rabbit, injecting BK into the lung parenchyma elicits reflex hyperpnea, tachypnea, hypotension, and bradycardia by stimulating pulmonary sympathetic afferents. To further explore bradykinin effects, breathing pattern (phrenic nerve and abdominal muscle activities) and hemodynamics (blood pressure and heart rate) were examined in anesthetized, open-chest, and mechanically ventilated rabbits. Three receptor agonists [bradykinin, selective B(1) (des-Arg(9)-BK), and selective B(2) (Tyr(8)-BK)], as well as three B(2) receptor antagonists, B6029 (N alpha-Adamantaneacetyl)-Bradykinin, B(1)650 (D-Arg-[Hyp(3), Thi(5,8), D-Phe(7)]-Bradykinin, or Hoe-140 (D-Arg-[Hyp(3), Thi(5), D-Tic(7), Oic(8)] bradykinin), were used to identify the responsible receptor subtype. In both intact and vagotomized rabbits, injecting BK or a selective B(2) agonist into the lung elicited similar cardiopulmonary responses. These reflex responses were greatly attenuated or blocked by pre-injecting B(2) antagonists into the right atrium or into the lung parenchyma. In contrast, the B(1) agonist elicited fewer cardiopulmonary effects in intact rabbits and had no effect in vagotomized rabbits. We conclude that BK stimulates pulmonary sympathetic afferents [Soukhova, G., Wang, Y., Ahmed, M., Walker, J., Yu, J., 2003. Bradykinin stimulates respiratory drive by activating pulmonary sympathetic afferents in the rabbit. J. Appl. Physiol. 95, 241-249.; Wang, Y., Soukhova, G., Proctor, M., Walker, J., Yu, J., 2003. Bradykinin causes hypotension by activating pulmonary sympathetic afferents in the rabbit. J. Appl. Physiol. 95, 233-240.], eliciting a characteristic cardiopulmonary reflex via B(2) receptors.
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Ferreira S, Winck J, Bettencourt P, Rocha-Goncalves F. Heart failure and sleep apnoea: to sleep perchance to dream. Eur J Heart Fail 2005; 8:227-36. [PMID: 16185920 DOI: 10.1016/j.ejheart.2005.07.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 05/12/2005] [Accepted: 07/26/2005] [Indexed: 11/17/2022] Open
Abstract
Heart failure and sleep apnoea are major health problems with an increasingly recognized association; evidence suggests that sleep apnoea may play a role in the progression of heart failure. However, confounding factors such as obesity, hypertension and coronary heart disease make this relationship uncertain and an independent correlation remains unproven. Diagnosis of sleep apnoea is suboptimal, as it is often asymptomatic and polysomnography is expensive and time-consuming. A simple and reliable screening protocol is required. All heart failure patients should be considered to be at high risk of sleep apnoea, as this association might be linked to adverse outcome. Continuous positive airway pressure has shown some beneficial effects, but long-term outcome and improvement in survival remains to be demonstrated. Despite recent advances in the understanding of the complex relationship between heart failure and sleep apnoea, there are a number of areas requiring further investigation, which may have important implications for the management and prognosis of a significant number of patients.
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Arzt M, Schulz M, Wensel R, Montalvàn S, Blumberg FC, Riegger GAJ, Pfeifer M. Nocturnal Continuous Positive Airway Pressure Improves Ventilatory Efficiency During Exercise in Patients With Chronic Heart Failure. Chest 2005; 127:794-802. [PMID: 15764759 DOI: 10.1378/chest.127.3.794] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVES Chronic heart failure is closely related to impaired cardiorespiratory reflex control, including decreased ventilatory efficiency during exercise (Ve/Vco(2)-slope) and central sleep apnea (CSA). Continuous positive airway pressure (CPAP) and nocturnal oxygen therapy alleviate CSA. The aim of the present study was to compare the effects of nocturnal CPAP and oxygen therapy on Ve/Vco(2)-slope. DESIGN AND SETTING Prospective controlled trial at a university hospital. PATIENTS Twenty-six stable patients with chronic heart failure and CSA. INTERVENTION AND MEASUREMENTS Ten patients received nocturnal oxygen, and 16 patients were assigned to CPAP treatment. At baseline and after 12 weeks of treatment, symptom-limited cardiopulmonary exercise testing was performed on a cycle ergometer. Expiratory gas was analyzed breath by breath for evaluation of ventilation and ventilatory efficiency in combination with arteriocapillary blood gas analysis during rest and exercise. RESULTS CPAP treatment significantly reduced the Ve/Vco(2)-slope (31.2 +/- 1.6 vs 26.2 +/- 1.0, p = 0.005) and improved the left ventricular ejection fraction (LVEF) [31.7 +/- 2.6% vs 35.7 +/- 2.7%, p = 0.041]. CPAP treatment significantly reduced the apnea-hypopnea index (AHI) [35.9 +/- 4.0/h vs 12.2 +/- 3.6/h, p = 0.002]. Peak oxygen consumption (Vo(2)) [16.2 +/- 1.1 L/min/kg vs 16.3 +/- 1.2 L/min/kg, p = 0.755] remained similar after CPAP treatment. Oxygen therapy reduced the AHI (28.8 +/- 3.2/h vs 8.7 +/- 4.1/h, p = 0.019), but did not improve exercise capacity (peak Vo(2), 15.4 +/- 1.5 L/min/kg vs 15.6 +/- 1.9 L/min/kg, p = 0.760), LVEF (30.9 +/- 2.4% vs 32.5 +/- 2.3%, p = 0.231), or the Ve/Vco(2)-slope (30.0 +/- 1.5 vs 29.8 +/- 1.5, p = 0.646). CONCLUSION Nocturnal CPAP and oxygen therapy alleviate CSA to a similar degree. Only CPAP therapy may improve ventilatory efficiency during exercise and may have favorable effects on LVEF. Therefore, our data suggest that CPAP is advantageous compared to oxygen in the treatment of CSA in patients with chronic heart failure.
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Affiliation(s)
- Michael Arzt
- Department of Internal Medicine II, University of Regensburg, Germany.
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Garrigue S, Bordier P, Barold SS, Clementy J. Sleep Apnea:. A New Indication for Cardiac Pacing? PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2004; 27:204-11. [PMID: 14764171 DOI: 10.1111/j.1540-8159.2004.00411.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In the general adult population, prevalence of sleep apnea syndrome reaches 4% in men and 2% in women. Continuous positive airway pressure is the most efficient treatment. At the present time, although severe atrial bradycardias could occur during sleep apnea episodes, cardiac pacing has not been demonstrated as an efficient treatment for those bradycardias. Treating sleep apnea generally reduces the number of bradyarrhythmias. However, recent studies reported a beneficial effect of atrial pacing on the sleep apnea burden. The mechanisms rely on two phenomena: first to counteract nocturnal hypervagotonia, and second to treat heart failure. By increasing the heart rate, cardiac output improves, which mitigates pulmonary subedema. Consequently, stimulation of the pulmonary afferent vagal fibers is diminished, which reduces central sleep apnea incidence. During nocturnal hypervagotonia, snoring and obstructive apnea episodes are increased, mainly due to an excessive muscular relaxation of the upper airway area inducing cyclical substantial decreases in the airway caliper. In patients with a low heart rate, atrial pacing can counteract hypervagotonia by enhancing the sympathetic tone and modifying the degree of vigilance. Accordingly, in the near future, sleep apnea treatment might potentially rely on atrial pacing in bradycardic patients with hypervagotonia (with or without heart failure). The role of the physician would then be not only to diagnose sleep apnea, but also to identify potential responders to cardiac pacing.
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Affiliation(s)
- Stephany Garrigue
- Clinical Electrophysiology and Cardiac Pacing Department, Hôpital Cardiologique du Haut Lévêque, Pessac, France.
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Garrigue S, Bordier P, Clémenty J. Apnées du sommeil et stimulation cardiaque : mécanismes d’action et perspectives. Ann Cardiol Angeiol (Paris) 2003; 52:239-45. [PMID: 14603705 DOI: 10.1016/s0003-3928(03)00083-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In an adult population, the prevalence of sleep apnea is 4% for men and 2% for women. Generally, nasal positive pressure ventilation is the best therapeutic option. To date, and in spite of the possible presence of marked brady-arrhythmias during sleep apnea, there is no recognised indication for Pacemaker implantation. However, recent data show the potential benefit of permanent cardiac stimulation in these patients. Increasing heart rate (using atrial pacing) improves cardiac output, and reduces pulmonary congestion and pulmonary vagal afferent nerves are no longer stimulated. The incidence of central sleep apnea is thereby reduced. Excessive nocturnal vagal tone increases snoring and sleep apnea, because of excessive relaxation of the oropharyngeal muscles. In patients with bradycardia, atrial stimulation may oppose increased vagal tone, by stimulating the sympathetic system or maintaining it at a minimal level. It is therefore possible that cardiac stimulation will become part of the treatment of sleep apnea in patients with documented bradycardia and/or heart failure.
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Affiliation(s)
- S Garrigue
- Hôpital cardiologique du Haut-Lévêque, 19, avenue de Magellan, 33600 Bordeaux-Pessac, France.
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Wang Y, Soukhova G, Proctor M, Walker J, Yu J. Bradykinin causes hypotension by activating pulmonary sympathetic afferents in the rabbit. J Appl Physiol (1985) 2003; 95:233-40. [PMID: 12679362 DOI: 10.1152/japplphysiol.00584.2002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bradykinin (BK) activates sympathetic afferents in the heart, intestine, and kidney, and it alters hemodynamics. However, we know little about the influence of pulmonary sympathetic afferents on circulation. Activation of pulmonary afferents by directly injecting stimulants into the lung parenchyma permits examination of reflexes that originate in the lung without confounding effects from the systemic circulation. In the present study, we tested the hypothesis that pulmonary sympathetic afferents exert a significant influence on hemodynamics. We examined reflex effects of injecting BK (1 microg/kg in 0.1 ml) into the lung parenchyma on circulation in anesthetized, open-chest, artificially ventilated rabbits. BK significantly decreased mean arterial blood pressure (BP) (27 +/- 3 mmHg) and heart rate (19 +/- 4 beats/min). Both effects remained after bilateral vagotomy. To rule out possible direct systemic vasodilation by BK, we examined renal sympathetic nerve activity (RSNA) in response to BK injection and examined BP responses to injection of ACh (0.1 ml of 10-4 M). BK suppressed the RSNA before and after vagotomy. ACh did not change BP when injected into the lung parenchyma, but it decreased BP (31 +/- 3 mmHg) when injected into the right atrium. Our data indicate that activating pulmonary sympathetic afferents reflexly suppresses hemodynamics.
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Affiliation(s)
- Y Wang
- Department of Medicine, University of Louisville, Louisville, KY 40292, USA
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Soukhova G, Wang Y, Ahmed M, Walker JF, Yu J. Bradykinin stimulates respiratory drive by activating pulmonary sympathetic afferents in the rabbit. J Appl Physiol (1985) 2003; 95:241-9. [PMID: 12679361 DOI: 10.1152/japplphysiol.00582.2002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We recently identified a vagally mediated excitatory lung reflex by injecting hypertonic saline into the lung parenchyma (Yu J, Zhang JF, and Fletcher EC. J Appl Physiol 85: 1485-1492, 1998). This reflex increased amplitude and burst rate of phrenic (inspiratory) nerve activity and suppressed external oblique abdominal (expiratory) muscle activity. In the present study, we tested the hypothesis that bradykinin may activate extravagal pathways to stimulate breathing by assessing its reflex effects on respiratory drive. Bradykinin (1 microg/kg in 0.1 ml) was injected into the lung parenchyma of anesthetized, open-chest and artificially ventilated rabbits. In most cases, bradykinin increased phrenic amplitude, phrenic burst rate, and expiratory muscle activity. However, a variety of breathing patterns resulted, ranging from hyperpnea and tachypnea to rapid shallow breathing and apnea. Bradykinin acts like hypertonic saline in producing hyperpnea and tachypnea, yet the two agents clearly differ. Bradykinin produced a higher ratio of phrenic amplitude to inspiratory time and had longer latency than hypertonic saline. Although attenuated, bradykinin-induced respiratory responses persisted after vagotomy. We conclude that bradykinin activates multiple afferent pathways in the lung; portions of its respiratory reflexes are extravagal and arise from sympathetic afferents.
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Affiliation(s)
- G Soukhova
- Department of Medicine, University of Louisville, Louisville, KY 40292, USA
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Yu J, Wang YF, Zhang JW. Structure of slowly adapting pulmonary stretch receptors in the lung periphery. J Appl Physiol (1985) 2003; 95:385-93. [PMID: 12665534 DOI: 10.1152/japplphysiol.00137.2003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary sensory receptors are the initiating sites for lung reflexes; however, little is known about their structure, especially the relationship between the structure and function of these receptors. Using a novel approach (combining electrophysiological and morphological techniques), we examined the structures of the typical slowly adapting pulmonary stretch receptors (SARs) located in the lung periphery. We recorded SAR activities in the cervical vagus nerve, identified the receptive field, dissected the SARs in blocks, fixed and processed these blocks for immunohistochemical staining using anti-Na+/K+-ATPase, and examined the blocks under a confocal microscope. These SAR structures have multiple endings that have terminal knobs. Some structures that are located in the airway walls have terminal knobs buried in smooth muscle. Others are in the most peripheral part of the lung, and their terminal knobs have no obvious relation to smooth muscle, suggesting that muscle contraction may not be a direct factor for SAR activation.
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Affiliation(s)
- J Yu
- Department of Medicine, University of Louisville, Louisville, KY 40292, USA. (
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Affiliation(s)
- T Douglas Bradley
- University of Toronto Centre for Sleep Medicine and Circadian Biology, Toronto, Ontario, Canada.
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Affiliation(s)
- T Douglas Bradley
- University of Toronto Centre for Sleep Medicine and Circadian Biology, Toronto, Ontario, Canada.
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50
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Affiliation(s)
- R S Leung
- University of Toronto Centre for Sleep and Chronobiology, the Cardiopulmonary Sleep Disorders and Research Centre of the Toronto General Hospital/University Health Network, Toronto, Ontario, Canada
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