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Ikoma T, Narumi T, Akita K, Sato R, Masuda T, Kaneko H, Toda M, Mogi S, Sano M, Suwa K, Naruse Y, Ohtani H, Saotome M, Maekawa Y. Association of an Increased Abnormal Mitochondria Ratio in Cardiomyocytes with a Prolonged Oxygen Uptake Time Constant during Cardiopulmonary Exercise Testing of Patients with Non-ischemic Cardiomyopathy. Intern Med 2023; 62:2163-2170. [PMID: 36450468 PMCID: PMC10465282 DOI: 10.2169/internalmedicine.0697-22] [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: 07/20/2022] [Accepted: 10/04/2022] [Indexed: 12/03/2022] Open
Abstract
Objective The cardiac function, blood distribution, and oxygen extraction in the muscles as well as the pulmonary function determine the oxygen uptake (VO2) kinetics at the onset of exercise. This factor is called the VO2 time constant, and its prolongation is associated with an unfavorable prognosis for heart failure (HF). The mitochondrial function of skeletal muscle is known to reflect exercise tolerance. Morphological changes and dysfunction in cardiac mitochondria are closely related to HF severity and its prognosis. Although mitochondria play an important role in generating energy in cardiomyocytes, the relationship between cardiac mitochondria and the VO2 time constant has not been elucidated. Methods We calculated the ratio of abnormal cardiac mitochondria in human myocardial biopsy samples using an electron microscope and measured the VO2 time constant during cardiopulmonary exercise testing. The VO2 time constant was normalized by the fat-free mass index (FFMI). Patients Fifteen patients with non-ischemic cardiomyopathy (NICM) were included. Patients were divided into two groups according to their median VO2 time constant/FFMI value. Results Patients with a low VO2 time constant/FFMI value had a lower abnormal mitochondria ratio than those with a high VO2 time constant/FFMI value. A multiple linear regression analysis revealed that the ratio of abnormal cardiac mitochondria was independently associated with a high VO2 time constant/FFMI. Conclusion An increased abnormal cardiac mitochondria ratio might be associated with a high VO2 time constant/FFMI value in patients with NICM.
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Affiliation(s)
- Takenori Ikoma
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Taro Narumi
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Keitaro Akita
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Ryota Sato
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Takayuki Masuda
- Department of Rehabilitation, Hamamatsu University Hospital, Japan
| | - Hanami Kaneko
- Department of Rehabilitation, Hamamatsu University Hospital, Japan
| | - Masahiro Toda
- Department of Rehabilitation, Hamamatsu University Hospital, Japan
| | - Satoshi Mogi
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Makoto Sano
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Kenichiro Suwa
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Yoshihisa Naruse
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Hayato Ohtani
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Masao Saotome
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
| | - Yuichiro Maekawa
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan
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Relationships among norepinephrine levels, exercise capacity, and chronotropic responses in heart failure patients. Heart Fail Rev 2023; 28:35-45. [PMID: 35325323 DOI: 10.1007/s10741-022-10232-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/15/2022] [Indexed: 02/07/2023]
Abstract
In heart failure (HF) patients, the pathophysiological mechanisms of severe exercise intolerance and impaired exercise capacity are related to both central and peripheral abnormalities. The central abnormalities in HF patients include impaired cardiac function and chronotropic incompetence (CI). Indeed, CI, the inability to adequately increase heart rate (HR) from rest to exercise often exhibited by HF patients, is related to activation of the sympathetic nervous system (SNS) yielding a rise in circulating norepinephrine (NE). CI may result from downregulation of β-adrenergic receptors, β-blocker usage, high baseline HR, or due to a combination of factors. This paper discusses the role of elevated NE in altering chronotropic responses in HF patients and consequently resulting in impaired exercise capacity. We suggest that future research should focus on the potential treatment of CI with rate-adaptive pacing, using a sensor to measure physical activity, without inducing deleterious hormonal activation of the sympathetic system.
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Paulin FV, Goelzer LS, Müller PDT. Vitamin B 12 Supplementation and NT-proBNP Levels in COPD Patients: A Secondary Analysis of a Randomized and Controlled Study in Rehabilitation. Front Neurosci 2020; 14:740. [PMID: 32760247 PMCID: PMC7372128 DOI: 10.3389/fnins.2020.00740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 06/23/2020] [Indexed: 12/29/2022] Open
Abstract
Purpose There is evidence of complex interaction between vitamin B12 (vB12) level, hyperhomocysteinemia (HyCy), and natriuretic peptide secretion. Exercise training could also modulate such interaction. In this secondary analysis of a Randomized Clinical Trial performed in a chronic obstructive pulmonary disease (COPD) rehabilitation setting, our primary objective was to investigate the interaction between vB12 supplementation, exercise training, and changes in NT-proBNP levels after 8 weeks of intervention. Secondary objectives were to explore the correlations between acute changes in NT-proBNP levels with (i) acute exercise and (ii) oxygen uptake (V’O2) kinetics during rest-to-exercise transition. Methods Thirty-two subjects with COPD were randomized into four groups: Rehabilitation+vB12 (n = 8), Rehabilitation (n = 8), vB12 (n = 8), or Maltodextrin(n = 8). They were evaluated at baseline and after 8 weeks, during resting and immediately after maximal exercise constant work-rate tests (CWTs, Tlim), for NT-proBNP plasmatic levels. Results After interaction analysis, the supplementation with vB12 significantly changed the time course of NT-proBNP responses during treatment (p = 0.048). However, the final analysis could not support a significant change in NT-proBNP levels owing to high-intensity constant work-rate exercise (p-value > 0.05). There was a statistically significant correlation between V’O2 time constant and ΔNT-proBNP values (Tlim – rest) at baseline (p = 0.049) and 2 months later (p = 0.015), considering all subjects (n = 32). Conclusion We conclude that vB12 supplementation could modulate NT-proBNP secretion. Moreover, possibly, the slower the initial V’O2 adjustments toward a steady-state during rest-to-exercise transitions, the more severe the ventricular chamber volume/pressure stress recruitment, expressed through higher NT-proBNP secretion in subjects with larger V’O2 time constants, despite unchanged final acute exercise-induced neurohormone secretion.
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Affiliation(s)
- Fernanda Viana Paulin
- Laboratory of Respiratory Pathophysiology, Respiratory Division, Department of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - Leandro Steinhorst Goelzer
- Laboratory of Respiratory Pathophysiology, Respiratory Division, Department of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - Paulo de Tarso Müller
- Laboratory of Respiratory Pathophysiology, Respiratory Division, Department of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
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Hearon Jr CM, Sarma S, Dias KA, Hieda M, Levine BD. Impaired oxygen uptake kinetics in heart failure with preserved ejection fraction. Heart 2019; 105:1552-1558. [DOI: 10.1136/heartjnl-2019-314797] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/10/2019] [Accepted: 05/14/2019] [Indexed: 12/17/2022] Open
Abstract
ObjectiveThe time needed to increase oxygen utilisation to meet metabolic demand (V̇O2 kinetics) is impaired in heart failure (HF) with reduced ejection fraction and is an independent risk factor for HF mortality. It is not known if V̇O2 kinetics are slowed in HF with preserved ejection fraction (HFpEF). We tested the hypothesis that V̇O2 kinetics are slowed during submaximal exercise in HFpEF and that slower V̇O2 kinetics are related to impaired peripheral oxygen extraction.MethodsEighteen HFpEF patients (68±7 years, 10 women) and 18 healthy controls (69±6 years, 10 women) completed submaximal and peak exercise testing. Cardiac output (acetylene rebreathing, Q̇c), ventilatory oxygen uptake (V̇O2, Douglas bags) and arterial-venous O2 difference (a-vO2 difference) derived from Q̇c and V̇O2 were assessed during exercise. Breath-by-breath O2 uptake was measured continuously throughout submaximal exercise, and V̇O2 kinetics was quantified as mean response time (MRT).ResultsHFpEF patients had markedly slowed V̇O2 kinetics during submaximal exercise (MRT: control: 40.1±14.2, HFpEF: 65.4±27.7 s; p<0.002), despite no relative impairment in submaximal cardiac output (Q̇c: control: 8.6±1.7, HFpEF: 9.7±2.2 L/min; p=0.79). When stratified by MRT, HFpEF with an MRT ≥60 s demonstrated elevated Q̇c, and impaired peripheral oxygen extraction that was apparent during submaximal exercise compared with HFpEF with a MRT <60 s (submaximal a-vO2 difference: MRT <60 s: 9.7±2.1, MRT ≥60 s: 7.9±1.1 mL/100 mL; p=0.03).ConclusionHFpEF patients have slowed V̇O2 kinetics that are related to impaired peripheral oxygen utilisation. MRT can identify HFpEF patients with peripheral limitations to submaximal exercise capacity and may be a target for therapeutic intervention.
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5
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Yoshimura K, Urabe Y, Maeda N, Yuguchi S, Yoshida T. Dynamics of cardiorespiratory response during and after the six-minute walk test in patients with heart failure. Physiother Theory Pract 2018; 36:476-487. [DOI: 10.1080/09593985.2018.1489925] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Kae Yoshimura
- Department of Rehabilitation, The Sakakibara Heart Institute of Okayama, Okayama, Japan
- Department of Sports Rehabilitation, Graduate School of Biomedical & Health Sciences, Hiroshima University, Horoshima, Japan
| | - Yukio Urabe
- Department of Sports Rehabilitation, Graduate School of Biomedical & Health Sciences, Hiroshima University, Horoshima, Japan
| | - Noriaki Maeda
- Department of Sports Rehabilitation, Graduate School of Biomedical & Health Sciences, Hiroshima University, Horoshima, Japan
| | - Satoshi Yuguchi
- Department of Physical Therapy, Japan University of Health Sciences, Saitama, Japan
| | - Toshinobu Yoshida
- Department of Cardiovascular Medicine, The Sakakibara Heart Institute of Okayama, Okayama, Japan
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Woessner MN, Levinger I, Neil C, Smith C, Allen JD. Effects of Dietary Inorganic Nitrate Supplementation on Exercise Performance in Patients With Heart Failure: Protocol for a Randomized, Placebo-Controlled, Cross-Over Trial. JMIR Res Protoc 2018; 7:e86. [PMID: 29625952 PMCID: PMC5910532 DOI: 10.2196/resprot.8865] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 01/22/2023] Open
Abstract
Background Chronic heart failure is characterized by an inability of the heart to pump enough blood to meet the demands of the body, resulting in the hallmark symptom of exercise intolerance. Chronic underperfusion of the peripheral tissues and impaired nitric oxide bioavailability have been implicated as contributors to the decrease in exercise capacity in these patients. nitric oxide bioavailability has been identified as an important mediator of exercise tolerance in healthy individuals, but there are limited studies examining the effects in patients with chronic heart failure. Objective The proposed trial is designed to determine the effects of chronic inorganic nitrate supplementation on exercise tolerance in both patients with heart failure preserved ejection fraction (HFpEF) and heart failure reduced ejection fraction (HFrEF) and to determine whether there are any differential responses between the 2 cohorts. A secondary objective is to provide mechanistic insights into the 2 heart failure groups’ exercise responses to the nitrate supplementation. Methods Patients with chronic heart failure (15=HFpEF and 15=HFrEF) aged 40 to 85 years will be recruited. Following an initial screen cardiopulmonary exercise test, participants will be randomly allocated in a double-blind fashion to consume either a nitrate-rich beetroot juice (16 mmol nitrate/day) or a nitrate-depleted placebo (for 5 days). Participants will continue daily dosing until the completion of the 4 testing visits (maximal cardiopulmonary exercise test, submaximal exercise test with echocardiography, vascular function assessment, and vastus lateralis muscle biopsy). There will then be a 2-week washout period after which the participants will cross over to the other treatment and complete the same 4 testing visits. Results This study is funded by National Heart Foundation of Australia and Victoria University. Enrolment has commenced and the data collection is expected to be completed in mid 2018. The initial results are expected to be submitted for publication by the end of 2018. Conclusions If inorganic nitrate supplementation can improve exercise tolerance in patients with chronic heart failure, it has the potential to aid in further refining the treatment of patients in this population. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12615000906550; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=368912 (Archived by WebCite at http://www.webcitation.org/6xymLMiFK)
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Affiliation(s)
- Mary N Woessner
- Institute of Health and Sport, Victoria University, Melbourne, Australia.,Western Center for Health and Research Education, Victoria University, St Albans, Australia
| | - Itamar Levinger
- Institute of Health and Sport, Victoria University, Melbourne, Australia.,Australian Institute for Musculoskeletal Science, Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, Australia
| | - Christopher Neil
- Institute of Health and Sport, Victoria University, Melbourne, Australia.,Department of Medicine-Western Health, University of Melbourne, Melbourne, Australia
| | - Cassandra Smith
- Institute of Health and Sport, Victoria University, Melbourne, Australia.,Australian Institute for Musculoskeletal Science, Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, Australia
| | - Jason D Allen
- Institute of Health and Sport, Victoria University, Melbourne, Australia.,Western Center for Health and Research Education, Victoria University, St Albans, Australia.,Department of Kinesiology, University of Virginia, Charlottesville, VA, United States
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Benson AP, Bowen TS, Ferguson C, Murgatroyd SR, Rossiter HB. Data collection, handling, and fitting strategies to optimize accuracy and precision of oxygen uptake kinetics estimation from breath-by-breath measurements. J Appl Physiol (1985) 2017; 123:227-242. [PMID: 28450551 DOI: 10.1152/japplphysiol.00988.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 03/20/2017] [Accepted: 04/19/2017] [Indexed: 11/22/2022] Open
Abstract
Phase 2 pulmonary oxygen uptake kinetics (ϕ2 τV̇o2P) reflect muscle oxygen consumption dynamics and are sensitive to changes in state of training or health. This study identified an unbiased method for data collection, handling, and fitting to optimize V̇o2P kinetics estimation. A validated computational model of V̇o2P kinetics and a Monte Carlo approach simulated 2 × 105 moderate-intensity transitions using a distribution of metabolic and circulatory parameters spanning normal health. Effects of averaging (interpolation, binning, stacking, or separate fitting of up to 10 transitions) and fitting procedures (biexponential fitting, or ϕ2 isolation by time removal, statistical, or derivative methods followed by monoexponential fitting) on accuracy and precision of V̇o2P kinetics estimation were assessed. The optimal strategy to maximize accuracy and precision of τV̇o2P estimation was 1-s interpolation of 4 bouts, ensemble averaged, with the first 20 s of exercise data removed. Contradictory to previous advice, we found optimal fitting procedures removed no more than 20 s of ϕ1 data. Averaging method was less critical: interpolation, binning, and stacking gave similar results, each with greater accuracy compared with analyzing repeated bouts separately. The optimal procedure resulted in ϕ2 τV̇o2P estimates for transitions from an unloaded or loaded baseline that averaged 1.97 ± 2.08 and 1.04 ± 2.30 s from true, but were within 2 s of true in only 47-62% of simulations. Optimized 95% confidence intervals for τV̇o2P ranged from 4.08 to 4.51 s, suggesting a minimally important difference of ~5 s to determine significant changes in τV̇o2P during interventional and comparative studies.NEW & NOTEWORTHY We identified an unbiased method to maximize accuracy and precision of oxygen uptake kinetics (τV̇o2P) estimation. The optimum number of bouts to average was four; interpolation, bin, and stacking averaging methods gave similar results. Contradictory to previous advice, we found that optimal fitting procedures removed no more than 20 s of phase 1 data. Our data suggest a minimally important difference of ~5 s to determine significant changes in τV̇o2P during interventional and comparative studies.
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Affiliation(s)
- Alan P Benson
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom; .,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - T Scott Bowen
- Heart Centre, University of Leipzig, Leipzig, Germany
| | - Carrie Ferguson
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom.,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Scott R Murgatroyd
- Neurosciences Intensive Care Unit, Wessex Neurological Centre, University Hospital Southampton, Southampton, United Kingdom; and
| | - Harry B Rossiter
- Rehabilitation Clinical Trials Center, Division of Respiratory and Critical Care Physiology and Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California.,School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
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8
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Jung MH, Goetze JP, Boesgaard S, Gustafsson F. Neurohormonal activation and exercise tolerance in patients supported with a continuous-flow left ventricular assist device. Int J Cardiol 2016; 220:196-200. [DOI: 10.1016/j.ijcard.2016.06.245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 06/26/2016] [Indexed: 10/21/2022]
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9
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Hummel SL, Herald J, Alpert C, Gretebeck KA, Champoux WS, Dengel DR, Vaitkevicius PV, Alexander NB. Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction. J Geriatr Cardiol 2016; 13:450-7. [PMID: 27594875 PMCID: PMC4984569 DOI: 10.11909/j.issn.1671-5411.2016.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023] Open
Abstract
BACKGROUND Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction. METHODS Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake (VO2peak), oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go (GUG), Comfortable Gait Speed (CGS), Unipedal Stance (US)], and self-reported physical activity (PA). RESULTS Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO2peak, but weakly associated with PA. CONCLUSIONS Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO2 peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF.
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Affiliation(s)
- Scott L Hummel
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | - John Herald
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Craig Alpert
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | | | - Wendy S Champoux
- William Beaumont School of Medicine, Oakland University, Royal Oak, MI, USA
| | - Donald R Dengel
- School of Kinesiology, University of Minnesota, Minneapolis, MN, USA
| | | | - Neil B Alexander
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
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CHO YOUNGKUEN, KIM SEONGGUK, LIM DOHYUNG, KIM DONGHYUN, KIM HANSUNG, KO CHANGYONG. MUSCLES IMPULSES USING TOP-LOADER TYPE OF WASHING MACHINE WITH DIFFERENT ENTRANCE HEIGHTS AND DRUM DEPTHS. J MECH MED BIOL 2014. [DOI: 10.1142/s0219519414400168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study was conducted to evaluate impulses in muscles during washing using top-loader type of washing machine and to predict the risk of musculoskeletal disorders. Experimental and virtual three-dimensional motion analyses were performed repeatedly with six healthy females using a top-loader type of washing machine at different entrance heights and drum depths. We calculated impulses of muscles from the motion data. Impulses of the latissimus dorsi and erector spinae muscles were the highest of those in the muscles.
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Affiliation(s)
- YOUNG-KUEN CHO
- Department of Biomedical Engineering and Research, Yonsei University, Wonju, Gangwon, 220842, South Korea
| | - SEONG GUK KIM
- Department of Biomedical Engineering and Research, Yonsei University, Wonju, Gangwon, 220842, South Korea
| | - DOHYUNG LIM
- Department of Mechanical Engineering, Faculty of Mechanical and Aerospace Engineering, College of Engineering, Sejong University, Seoul, 143747, South Korea
| | - DONG HYUN KIM
- Department of Biomedical Engineering and Research, Yonsei University, Wonju, Gangwon, 220842, South Korea
| | - HAN SUNG KIM
- Department of Biomedical Engineering and Research, Yonsei University, Wonju, Gangwon, 220842, South Korea
| | - CHANG-YONG KO
- Korea Orthopedics & Rehabilitation Engineering Center, Incheon, 403-712, Republic of Korea
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Barton M, Schiffrin EL. In Memoriam: Wolfgang Kiowski, M.D. (1949–2012) - Pioneer in clinical endothelin research. Life Sci 2014; 118:91-6. [DOI: 10.1016/j.lfs.2014.08.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Sellar CM, Bell GJ, Haennel RG, Au HJ, Chua N, Courneya KS. Feasibility and efficacy of a 12-week supervised exercise intervention for colorectal cancer survivors. Appl Physiol Nutr Metab 2013; 39:715-23. [PMID: 24869975 DOI: 10.1139/apnm-2013-0367] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Exercise training improves health-related physical fitness and patient-reported outcomes in cancer survivors, but few interventions have targeted colorectal cancer (CRC) survivors. This investigation aimed to determine the feasibility and efficacy of a 12-week supervised exercise training program for CRC survivors. Feasibility was assessed by tracking participant recruitment, loss to follow-up, assessment completion rates, participant evaluation, and adherence to the intervention. Efficacy was determined by changes in health-related physical fitness. Over a 1-year period, 72 of 351 (21%) CRC survivors screened were eligible for the study and 29 of the 72 (40%) were enrolled. Two participants were lost to follow-up (7%) and the completion rate for all study assessments was ≥93%. Mean adherence to the exercise intervention was 91% (standard deviation = ±18%), with a median of 98%. Participants rated the intervention positively (all items ≥ 6.6/7) and burden of testing low (all tests ≤ 2.4/7). Compared with baseline, CRC survivors showed improvements in peak oxygen uptake (mean change (MC) = +0.24 L·min(-1), p < 0.001), upper (MC = +7.0 kg, p < 0.001) and lower (MC = +26.5 kg, p < 0.001) body strength, waist circumference (MC = -2.1 cm, p = 0.005), sum of skinfolds (MC = -7.9 mm, p = 0.006), and trunk forward flexion (MC = +2.5 cm, p = 0.019). Exercise training was found to be feasible and improved many aspects of health-related physical fitness in CRC survivors that may be associated with improved quality of life and survival in these individuals.
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Affiliation(s)
- Christopher M Sellar
- a Faculty of Physical Education and Recreation, E459 Van Vliet Center, University of Alberta, Edmonton, AB T6G 2H9, Canada
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Chatterjee NA, Murphy RM, Malhotra R, Dhakal BP, Baggish AL, Pappagianopoulos PP, Hough SS, Semigran MJ, Lewis GD. Prolonged mean VO2 response time in systolic heart failure: an indicator of impaired right ventricular-pulmonary vascular function. Circ Heart Fail 2013; 6:499-507. [PMID: 23572493 DOI: 10.1161/circheartfailure.112.000157] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND In patients with left ventricular systolic dysfunction (LVSD), the rate at which oxygen uptake (VO2) increases on initiation of exercise is inadequate to match metabolic demands. To gain mechanistic insights into delayed VO2 kinetics in LVSD, we simultaneously assessed hemodynamic measurements, ventilatory parameters, and peripheral oxygen usage during exercise. METHODS AND RESULTS Forty-two patients with symptomatic LVSD (age, 59±2 years [mean±SEM]; LV ejection fraction, 30±1%) and 17 controls (LV ejection fraction, 68±1%) underwent maximum upright cycle ergometry cardiopulmonary exercise testing. Hemodynamic monitoring and first-pass radionuclide ventriculography were performed at rest and during exercise. VO2 kinetics were quantified by mean response time (MRT), which was significantly longer in patients with LVSD compared with controls (64±3 versus 45±5 s; P=0.004). In LVSD patients, MRT was associated with higher biventricular filling pressures and reduced cardiac output during early exercise. LVSD patients with MRT ≥60 s, compared with LVSD subjects with MRT <60 s, demonstrated greater impairment in right ventricular-pulmonary vascular function during exercise as evidenced by lower right ventricular ejection fraction (35±2 versus 45±2%; P=0.03), steeper increment in transpulmonary gradient relative to cardiac output (3.7 versus 2.2 mm Hg/L; P<0.001), and increased ventilatory dead-space fraction (17±1 versus 12±2%; P=0.03). In contrast, MRT was not associated with LV ejection fraction (rest, exercise), PaO2, hemoglobin, or resting pulmonary function test results. CONCLUSIONS Delayed oxygen uptake on initiation of exercise (ie, MRT ≥60 s) in LVSD is closely related to impaired right ventricular-pulmonary vascular function and may represent an important surrogate for inability to augment RV performance during physical activity in patients with heart failure.
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Affiliation(s)
- Neal A Chatterjee
- Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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14
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Borghi-Silva A, Beltrame T, Reis MS, Sampaio LMM, Catai AM, Arena R, Costa D. Relationship between oxygen consumption kinetics and BODE Index in COPD patients. Int J Chron Obstruct Pulmon Dis 2012; 7:711-8. [PMID: 23118534 PMCID: PMC3484529 DOI: 10.2147/copd.s35637] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND AND OBJECTIVE Patients with chronic obstructive pulmonary disease (COPD) present with reduced exercise capacity due to impaired oxygen consumption (VO(2)), caused primarily by pulmonary dysfunction and deleterious peripheral adaptations. Assuming that COPD patients present with slower VO(2) and heart rate (HR) on-kinetics, we hypothesized that this finding is related to disease severity as measured by the BODE Index. In this context, the present study intends to evaluate the relationship between VO(2) uptake on-kinetics during high-intensity exercise and the BODE Index in patients with COPD. METHODS Twenty males with moderate-to-severe stable COPD and 13 healthy control subjects matched by age and sex were evaluated. COPD patients were screened by the BODE Index and then underwent an incremental cardiopulmonary exercise test and a constant speed treadmill session at 70% of maximal intensity for 6 minutes. The onset of the exercise (first 360 seconds) response for O(2) uptake and HR was modeled according to a monoexponential fit. RESULTS Oxygen consumption and HR on-kinetics were slower in the COPD group compared with controls. Additionally, VO(2) on-kinetic parameters revealed a strong positive correlation (r = 0.77, P < 0.05) with BODE scores and a moderate negative correlation with walking distance (r = -0.45, P < 0.05). CONCLUSION Our data show that moderate-to-severe COPD is related to impaired oxygen delivery and utilization during the onset of intense exercise.
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Affiliation(s)
- Audrey Borghi-Silva
- Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of São Carlos, São Carlos, SP, Brazil.
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Hogan CJ, Ward KR, Franzen DS, Rajendran B, Thacker LR. Sublingual tissue perfusion improves during emergency treatment of acute decompensated heart failure. Am J Emerg Med 2012; 30:872-80. [PMID: 21871763 PMCID: PMC3236806 DOI: 10.1016/j.ajem.2011.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/03/2011] [Accepted: 06/05/2011] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVES The aim of this study was to measure sublingual perfused capillary density (PCD) to assess sublingual microvascular perfusion during emergency department (ED) treatment of acute decompensated heart failure (ADHF). METHODS This prospective, observational study enrolled ED patients with ADHF, measuring pre- and post-ED treatment PCD. Sidestream dark-field imaging was analyzed by 3 investigators blinded to patient identifiers and time points. Patient demographics, ADHF etiology, serum brain natriuretic peptide, and hemoglobin were measured along with a visual analogue scale (VAS), which assessed patient baseline characteristics and response to ED treatment. A paired t test analyzed changes in PCD, mean arterial pressure (MAP), and patient assessment. Interrater variability was assessed with an intraclass correlation coefficient (ICC), with a P value <.05 considered significant for all testing. RESULTS Thirty-six patients were enrolled with a mean time between pretreatment and posttreatment PCD (±SD) of 138 ± 59 minutes and a hospital length of stay of 4.0 ± 4.1 days. During this time, PCD increased (difference, 1.3 mm/mm(2); 95% confidence interval, 0.4-2.1; P = .004), as did the MAP (P = .002), patient VAS score (P < .001), and observer VAS score (P < .001). There was no correlation between the change in PCD and time (R(2) = .016, P = .47), MAP (R(2) = .013, P = .54), or VAS scores. The ICC was 0.954. CONCLUSIONS Sublingual tissue perfusion is diminished in ADHF but increases with treatment. It may represent a quantitative way to evaluate ADHF in the ED setting.
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Affiliation(s)
- Christopher J Hogan
- Department of Emergency Medicine, Virginia Commonwealth University Medical Center, Medical College of Virginia Campus, Richmond, VA 23298-0401, USA.
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Fischler M, Maggiorini M, Dorschner L, Debrunner J, Bernheim A, Kiencke S, Mairbäurl H, Bloch KE, Naeije R, Rocca HPBL. Dexamethasone But Not Tadalafil Improves Exercise Capacity in Adults Prone to High-Altitude Pulmonary Edema. Am J Respir Crit Care Med 2009; 180:346-52. [DOI: 10.1164/rccm.200808-1348oc] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Candell-Riera J, Romero-Farina G, Aguadé-Bruix S, Castell-Conesa J, de León G, García-Dorado D. Prognostic value of myocardial perfusion-gated SPECT in patients with ischemic cardiomyopathy. J Nucl Cardiol 2009; 16:212-21. [PMID: 19159990 DOI: 10.1007/s12350-008-9042-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 11/17/2008] [Accepted: 11/20/2008] [Indexed: 11/29/2022]
Abstract
BACKGROUND There are no extensive series in which risk stratification of patients with ischemic cardiomyopathy (IC) is based on their rest and exercise and scintigraphic characteristics. The purpose of our study was to analyze rest and exercise myocardial perfusion-gated SPECT variables for prognosis in patients with ischemic IC. METHODS AND RESULTS Prospective cohort study. A study was performed in 167 patients with IC who consecutively underwent rest myocardial perfusion-gated SPECT. In addition, stress SPECT was performed on 137 of these patients. During an average follow-up of 2.3 +/- 1.2 years, cardiac mortality (CM) was 17.4%. Independent predictors of CM in rest-gated SPECT were the positive criteria for myocardial viability (P = 0.027; Hazard risk, HR: 5.1; 95% CI: 1.2-21.4). In the 137 patients who underwent stress-gated SPECT, predictors were scintigraphic criteria for viability plus ischemia (P = 0.026; HR: 3.6; 95% CI: 1.16-11.2) and exercise duration < or = 5 minutes (P = 0.04; HR: 2.7; 95% CI: 1.01-7.36). Coronary angiography variables, performed in 111 patients, did not significantly modify the prognostic value of non-invasive testing. CONCLUSION Myocardial perfusion-gated SPECT improves prognostic stratification of patients with IC.
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Affiliation(s)
- Jaume Candell-Riera
- Servei de Cardiologia, Area del Cor, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Paseo Vall d'Hebron 119-129, 08035, Barcelona, Spain.
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Baravelli M, Fantoni C, Rossi A, Cattaneo P, Forzani T, Bargiggia G, Anza' C. Can kinetics of oxygen uptake at onset of exercise identify contractile reserve in patients with ischemic left ventricular dysfunction? Int J Cardiol 2008; 129:427-9. [PMID: 17689747 DOI: 10.1016/j.ijcard.2007.06.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 06/30/2007] [Indexed: 10/23/2022]
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Improvement in Early Oxygen Uptake Kinetics With Left Ventricular Assist Device Support. ASAIO J 2008; 54:406-11. [DOI: 10.1097/mat.0b013e31817e2b79] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Maeder MT, Ammann P, Rickli H, Schoch OD, Korte W, Hürny C, Myers J, Münzer T. N-terminal pro-B-type natriuretic peptide and functional capacity in patients with obstructive sleep apnea. Sleep Breath 2007; 12:7-16. [PMID: 17906885 DOI: 10.1007/s11325-007-0143-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular abnormalities including left ventricular hypertrophy, left ventricular diastolic dysfunction, and endothelial dysfunction. The present study evaluated whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) and peak oxygen consumption (peak VO(2)), both integral markers of cardiovascular function, are related to OSAS severity. In addition, we tested whether NT-proBNP levels depend on body composition in OSAS patients, similar to what has been reported in patients without OSAS. Eighty-nine patients with untreated OSAS underwent NT-proBNP measurement, dual X-ray absorptiometry, and cardiopulmonary exercise testing. In a representative subgroup (n = 32), transthoracic echocardiography was performed. The severity of OSAS was classified based on apnea-hypopnea index (AHI) values as mild (AHI 5-15 h(-1)), moderate (AHI 15-30 h(-1)), and severe (AHI >30 h(-1)). OSAS was mild in 19 (21%), moderate in 21 (24%), and severe in 49 (55%) patients. NT-proBNP levels did not differ among patients with mild [30 (10-57)], moderate [37 (14-55)], and severe [24 (13-49) pg/ml; p = 0.8] OSAS and were not related to body mass index (r = 0.07; p = 0.5), percent lean body mass (r = -0.17; p = 0.1), and percent fat mass (r = 0.18; p = 0.1). Percent predicted peak VO(2) was on average normal and did not differ among patients with mild (115 +/- 26), moderate (112 +/- 23), and severe OSAS (106 +/- 29%; p = 0.4). Body weight-indexed peak VO(2) did not differ among patients with mild (31.9 +/- 10.3), moderate (32.1 +/- 7.9), and severe OSAS (30.0 +/- 9.9 ml kg(-1) min(-1); p = 0.6) either. Lower NT-proBNP (beta = -0.2; p = 0.02) was independently but weakly associated with higher body weight-indexed peak VO(2). In the echocardiography subgroup, NT-proBNP was not significantly related to left ventricular mass index (r = 0.26; p = 0.2). In conclusion, NT-proBNP and peak VO(2) are not related to OSAS severity, and NT-proBNP poorly reflects left ventricular hypertrophy in OSAS. The lack of a relationship between NT-proBNP and OSAS severity is not due to a significant influence of body composition on NT-proBNP. There is an association between higher NT-proBNP and lower peak VO(2), indicating that NT-proBNP is a marker of cardiorespiratory fitness in patients with OSAS. However, the association is too weak to be clinically useful.
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Affiliation(s)
- Micha T Maeder
- Division of Cardiology, Kantonsspital, St. Gallen, Switzerland.
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Maeder M, Wolber T, Rickli H, Myers J, Hack D, Riesen W, Weilenmann D, Ammann P. B-type natriuretic peptide kinetics and cardiopulmonary exercise testing in heart failure. Int J Cardiol 2007; 120:391-8. [PMID: 17182129 DOI: 10.1016/j.ijcard.2006.10.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2006] [Revised: 08/12/2006] [Accepted: 10/14/2006] [Indexed: 11/17/2022]
Abstract
BACKGROUND In patients with chronic heart failure (CHF), B-type natriuretic peptide (BNP) is related to peak oxygen consumption (peak VO2) and the relationship between minute ventilation and carbon dioxide production (VE/VCO2 slope). However, the exercise response depends on the mode of exercise. This study sought to compare peak treadmill and bicycle exercise responses with respect to their relationship with BNP and to assess whether BNP measured at rest or during exercise could identify patients with greater functional impairment and ventilatory inefficiency. METHODS Twenty-three patients with mild-to-moderate stable systolic CHF (age 72+/-8 years, left ventricular ejection fraction 32+/-7%) underwent treadmill and bicycle cardiopulmonary exercise testing within 5 (interquartile range 3-7) days. BNP was measured at rest and at peak exercise. RESULTS BNP at rest was an independent multivariate predictor of both peak VO2 and the VE/VCO2 slope for both exercise modes. However, the proportion of variance explained univariately and multivariately was < or = 0.55, indicating that BNP did not strongly explain the variation of peak VO2 and the VE/VCO2 slope. The exercise-induced rise in circulating BNP did not differ between the test modes [treadmill: 50 (24-89) pg/ml vs. bicycle: 46 (15-100) pg/ml; p=0.73]. BNP levels at peak exercise were strongly related to resting values, but did not provide additional information on peak VO2 or the VE/VCO2 slope. CONCLUSIONS In typical CHF patients, BNP measured at rest or at peak exercise does not strongly predict peak VO2 or the VE/VCO2 slope regardless of the exercise mode, and is therefore not a sufficiently accurate surrogate for cardiopulmonary exercise testing.
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Affiliation(s)
- Micha Maeder
- Division of Cardiology, Department of Internal Medicine, Kantonsspital St. Gallen, Switzerland.
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Witte KKA, Thackray SDR, Lindsay KA, Cleland JGF, Clark AL. Metabolic gas kinetics depend upon the level of exercise performed. Eur J Heart Fail 2007; 7:991-6. [PMID: 16115799 DOI: 10.1016/j.ejheart.2005.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2004] [Revised: 02/02/2005] [Accepted: 05/10/2005] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The kinetics of oxygen and carbon dioxide at the onset of and recovery from exercise are slowed in patients with chronic heart failure (CHF). The aim of the present study was to establish whether the kinetics of O2 are influenced by the work rate. METHODS Thirteen CHF patients and 12 control subjects underwent bicycle-based peak exercise testing with metabolic gas exchange analysis. Each subject then exercised at 15%, 25% and 50% of the maximal workload achieved until reaching steady state. Time constants for onset (T(onset)) and offset (T(offset)) for O2 uptake and CO2 output were correlated to the workload and the percentage of peak V(O2) performed during the steady state tests. RESULTS Patients had lower peak oxygen uptake (pV(O2)) and the relation between ventilation and carbon dioxide output was steeper in patients than controls. T(offset) for both oxygen (O2) and carbon dioxide (CO(2)) from peak exercise was significantly greater in the patients than the controls and correlated with peak V(O2) (r=0.56, p<0.005 and r=0.58, p<0.005). T(onset) and T(offset) for O2 were increased in patients for each of the steady state tests and peak V(O2) correlated with T for recovery of O2 (r=0.44; p<0.05 from 15%, r=0.35; p= or <0.05 from 25%, and r=0.54; p<0.01 from 50%). There was a correlation between the T(onset) (r=0.42; p<0.0005 for O2 and r=0.23; p<0.05 for CO2) and T(offset) (r=0.49; p<0.0001 for O2 and r=0.42; p<0.0005 for CO2) and oxygen uptake as a percentage of peak exercise. CONCLUSIONS This study demonstrates that the time constants of onset and offset for oxygen are dependent upon the degree of exertion performed relative to the individual's peak capacity.
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Affiliation(s)
- Klaus K A Witte
- Department of Academic Cardiology, Castle Hill Hospital, Castle Road, Cottingham, Hull HU16 5JQ, United Kingdom.
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Fitzsimons C, Simpson H, Young A, Greig C. Oxygen uptake kinetics measured at the onset of comfortable self-paced walking in elderly women after hip fracture. Eur J Appl Physiol 2007; 100:355-62. [PMID: 17429682 DOI: 10.1007/s00421-007-0437-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2007] [Indexed: 10/23/2022]
Abstract
The objectives of this study were to (1) evaluate the suitability of "comfortable" self-paced walking as a mode of exercise to study VO(2) kinetics, and (2) to investigate VO(2) kinetics after hip fracture using self-paced walking as the exercise mode. The study took place in a Scottish rehabilitation hospital physiotherapy gymnasium [hip fracture (HF) group] and a Scottish University Gymnasium [young (Y) and healthy elderly (HE) groups]. Fifteen women after HF (median age 81 years) and five Y and five older HE women (median ages 22 and 78 years, respectively) took part in the study. Volunteers completed three repeats of 3 min of "comfortable" self-paced walking on two occasions. The ensemble averaged VO(2) response from walks 2 and 3 on visits 1 and 2 were combined and characterised using nonlinear regression techniques to derive a Mean Response Time (MRT). Self-paced walking was described as "constant-load" exercise (coefficient of variation of lap speeds of <or=6%) in 13 of 15 cases in the HF group on at least one visit (100% of cases in Y and HE groups). Steady-state VO(2) was achieved in 3 min in 8 of HF group on Visit 1 and 10 on Visit 2 (100% of cases in Y and HE groups). MRTs for the HF group (51 s, N = 5, 4 repeats; N = 7, 2 repeats) were significantly higher than the Y and HE groups [Y group 22 s (N = 5, 4 repeats); HE group 36 s (N = 5, 4 repeats)]. Self-paced walking provided a suitable mode of exercise to investigate VO(2) kinetics in frail older women after HF and permitted the first characterisation of VO(2) kinetics in this patient group. This test provides a promising methodology to evaluate rehabilitation efforts in frail individuals.
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Affiliation(s)
- Claire Fitzsimons
- Sport, Culture and the Arts and SIPBS, University of Strathclyde, Glasgow, UK.
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Affiliation(s)
- Jorge P Ribeiro
- Cardiology Division, Hospital de Clínicas de Porto Alegre, RS, Brazil.
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Williams SG, Ng LL, O'Brien RJ, Taylor S, Wright DJ, Li YF, Tan LB. Complementary roles of simple variables, NYHA and N-BNP, in indicating aerobic capacity and severity of heart failure. Int J Cardiol 2005; 102:279-86. [PMID: 15982497 DOI: 10.1016/j.ijcard.2004.05.054] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Revised: 04/19/2004] [Accepted: 05/05/2004] [Indexed: 11/29/2022]
Abstract
AIMS The extent of exercise intolerance in patients with chronic heart failure (CHF) is dependent on and representative of the severity of heart failure. However, few primary care physicians have direct access to facilities for formal exercise testing. We have therefore explored whether information readily obtainable in the community can reliably predict the functional capacity of patients. METHODS AND RESULTS Ninety-six subjects with a wide range of cardiac function (10 healthy controls and 86 CHF patients with NYHA classes I-IV, LVEF 36.9+/-15.2%) were recruited into the study and had resting plasma N-BNP and cardiopulmonary exercise testing to measure peak oxygen consumption (VO2). Significantly higher N-BNP levels were found in the CHF group (299.3 [704.8] fmol/ml, median [IQR]) compared with the healthy control group (7.2 [51.2] fmol/ml), p<0.0001. There were significant correlations between peak VO2 and N-BNP levels (R=0.64, P<0.001), peak VO2 and NYHA class (R=0.76, P=0.001), but no significant correlation was seen between peak VO2 and LVEF (R=0.0788, P=0.33). Multivariate analysis identified plasma N-BNP (P<0.0001) and NYHA class (P<0.0001) as significant independent predictors of peak VO2. Logistic modelling with NYHA class and log N-BNP to predict peak VO2<20 ml/kg/min showed that the area under the curve of receiver-operating-characteristic (ROC) curve was 0.906 (95% CI 0.844-0.968). A nomogram based on the data has been constructed to allow clinicians to estimate the likelihood of peak VO2 to be <20 ml/kg/min for given values of plasma N-BNP and NYHA class. CONCLUSIONS By combining information from a simple objective blood test (N-BNP) and a simple scoring of functional status (NYHA), a clinician can deduce the aerobic exercise capacity and indirectly the extent of cardiac dysfunction of patients with CHF.
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Affiliation(s)
- S G Williams
- Academic Unit of Molecular Vascular Medicine, University of Leeds, Martin Wing, Leeds General Infirmary, Leeds, LS1 3EX, UK
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Hogenhuis J, Jaarsma T, Voors AA, van Veldhuisen DJ. BNP and functional status in heart failure. Cardiovasc Drugs Ther 2005; 18:507; author reply 509. [PMID: 15770439 DOI: 10.1007/s10557-004-6229-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abdulla J, K�ber L, Torp-Pedersen C. BNP and Functional Status in Heart Failure (Response). Cardiovasc Drugs Ther 2004. [DOI: 10.1007/s10557-004-6230-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dayi SU, Terzi S, Akbulut T, Akgöz H, Tartan Z, Gürkan U, Yilmazer S, Tayyareci G. Effect of acute blood pressure reduction on oxygen uptake kinetics at the onset of exercise in hypertensive patients. JAPANESE HEART JOURNAL 2004; 45:799-805. [PMID: 15557721 DOI: 10.1536/jhj.45.799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
The aim of the present study was to investigate the adverse effects of hypertension on the cardiovascular system in daily activities and the effect of acute blood pressure reduction on oxygen (O(2)) uptake kinetics. Twenty hypertensive patients were included in the study group. Patients performed treadmill exercise tests (2.5 km/hour and 5 inclines) twice, before and after blood pressure reduction with sublingual captopril. In the control group, ten hypertensive patients underwent two tests one hour apart without blood pressure reduction brought about by drug therapy. The changes in O(2) kinetic values (O(2) deficit and mean response time [MRT]) between the two tests were investigated. In the study group, the O(2) deficit and MRT values measured during the first exercise testing were found to be 547 +/- 183 mL and 40 +/- 9 seconds, while those in the second exercise testing were 401 +/- 127 mL and 34 +/- 7 seconds, respectively. In the control group, the O(2) deficit and MRT values measured during the first exercise test were 491 +/- 217 mL and 42 +/- 16 seconds and 515 +/- 159 mL and 41 +/- 13 seconds in the second exercise test. The differences in O(2) deficit and MRT in the study group were considered to be statistically significant (P = 0.008 and P = 0.004, respectively). Based on our findings, there was a significant improvement in O(2) kinetic values with an acute reduction in blood pressure in hypertensive patients, most likely as a result of an improved response in cardiac output.
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Affiliation(s)
- Sennur Unal Dayi
- Department of Cardiology, Siyami Ersek Thoracic and Cardiovascular Surgery Center, Istanbul, Turkey
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Williams SG, Ng LL, O'Brien RJ, Taylor S, Wright DJ, Tan LB. Is plasma N-BNP a good indicator of the functional reserve of failing hearts? The FRESH-BNP study. Eur J Heart Fail 2004; 6:891-900. [PMID: 15556051 DOI: 10.1016/j.ejheart.2004.03.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Revised: 02/16/2004] [Accepted: 03/13/2004] [Indexed: 11/22/2022] Open
Abstract
AIMS Whether plasma N-terminal brain natriuretic peptide (N-BNP) is useful in the diagnosis of heart failure (HF) depends traditionally on whether it is as good as the putative 'gold-standard', left ventricular ejection fraction (LVEF), in indicating cardiac dysfunction. However, since HF is primarily an impairment of function of the cardiac pump, we explored the relationship between N-BNP and direct and indirect indicators of cardiac pump dysfunction. METHODS AND RESULTS Eighty-six HF patients (mean age 56 years) with a range of LVEF's (mean 36.9+/-15.2%, range 15-66%) and 10 age-matched healthy controls were recruited into the study and had resting N-BNP measured. Cardiopulmonary exercise testing was performed to assess peak oxygen consumption (Vo(2)). A subgroup of 23 subjects underwent further exercise haemodynamic assessment to evaluate peak cardiac power output (CPO). The CHF group had significantly higher N-BNP (median [interquartile range]) levels (299 [705] fmol/ml) than the control group (7 [51] fmol/ml, P<0.005). Significant correlations between N-BNP and peak Vo(2), and N-BNP and peak CPO were observed (R> or =0.5, P<0.005). Although significant correlation was observed between N-BNP and LVEF (R=0.34, P=0.01), the correlations between LVEF and peak Vo(2) or peak CPO (all R<0.3, P>0.3) were not significant. Multivariate analysis identified plasma N-BNP and NYHA class, but not LVEF, as independent predictors of peak Vo(2). CONCLUSIONS We have found that N-BNP was surprisingly good as a simple indicator of cardiac pump dysfunction. Since heart failure is an inadequacy of function, these results strongly support the notion that N-BNP is a useful blood test in estimating the extent of cardiac pump dysfunction and helpful in establishing positive diagnosis of heart failure.
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Affiliation(s)
- Simon G Williams
- Academic Unit of Molecular Vascular Medicine, University of Leeds, Martin Wing, Leeds General Infirmary, Leeds LS1 3EX, UK
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de Groote P, Soudan B, Lamblin N, Rouaix-Emery N, Mc Fadden E, Meurice T, Mouquet F, Bauters C. Is hormonal activation during exercise useful for risk stratification in patients with moderate congestive heart failure? Am Heart J 2004; 148:349-55. [PMID: 15309008 DOI: 10.1016/j.ahj.2004.03.044] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND We previously demonstrated that A-type natriuretic peptide (ANP) at peak exercise was an independent predictor of cardiac survival. No data are available concerning the predictive value of B-type natriuretic peptide (BNP) at peak exercise. METHODS One hundred and fifty consecutive stable patients with moderate congestive heart failure (CHF) underwent echocardiography and a cardiopulmonary exercise test. Blood samples were drawn at rest and at peak exercise for the determination of plasma levels of ANP, BNP, and norepinephrine. RESULTS Exercise significantly increased plasma values of ANP, BNP, and norepinephrine. After a median follow-up period of 1171 days, there were 35 cardiac related deaths. Mortality rates at 1 and 2 years were 4% and 8%, respectively. Independent predictors of cardiac survival were percent of maximal predicted oxygen consumption (RR = 4.8 [2.1-11], P =.002), BNP at rest (RR = 2.5 [1.2-5.6], P =.01), and left atrial diameter (RR = 2.8 [1.2-6.5], P =.02). CONCLUSIONS In patients with stable, moderate CHF, plasma levels of ANP, BNP, and norepinephrine measured at peak exercise did not improve risk stratification. However, in addition to percent of maximal predicted oxygen consumption and left atrial diameter, plasma level of BNP at rest was an independent predictor of survival in CHF patients with low risk of cardiac events.
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Affiliation(s)
- Pascal de Groote
- TOP Service de Cardiologie C, Hôpital Cardiologique, Lille Cedex, France.
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Cade WT, Fantry LE, Nabar SR, Shaw DK, Keyser RE. Impaired oxygen on-kinetics in persons with human immunodeficiency virus are not due to highly active antiretroviral therapy. Arch Phys Med Rehabil 2004; 84:1831-8. [PMID: 14669191 DOI: 10.1016/j.apmr.2003.03.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To determine the effects of human immunodeficiency virus (HIV) and highly active antiretroviral therapy (HAART) on oxygen on-kinetics in HIV-positive persons. DESIGN Quasi-experimental cross-sectional. SETTING Infectious disease clinic and exercise laboratory. PARTICIPANTS Referred participants (N=39) included 13 HIV-positive participants taking HAART, 13 HIV-positive participants not taking HAART, and 13 noninfected controls. INTERVENTIONS Participants performed 1 submaximal exercise treadmill test below the ventilatory threshold, 1 above the ventilatory threshold, and 1 maximal treadmill exercise test to exhaustion. MAIN OUTCOME MEASURES Change in oxygen consumption (Delta.VO2) and oxidative response index (Delta.VO2/mean response time). RESULTS Delta.VO2 was significantly lower in both HIV-positive participants taking (946.5+/-68.1mL) and not taking (871.6+/-119.6mL) HAART than in controls (1265.3+/-99.8mL) during submaximal exercise above the ventilatory threshold. The oxidative response index was also significantly lower (P<.05) in HIV-positive participants both taking (15.0+/-1.3mL/s) and not taking (15.1+/-1.7mL/s) HAART than in controls (20.8+/-2.1mL/s) during exercise above the ventilatory threshold. CONCLUSION Oxygen on-kinetics during submaximal exercise above the ventilatory threshold was impaired in HIV-positive participants compared with a control group, and it appeared that the attenuated oxygen on-kinetic response was primarily caused by HIV infection rather than HAART.
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Affiliation(s)
- W Todd Cade
- Department of Physical Therapy, University of Maryland School of Medicine, Baltimore, MD, USA.
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Taniguchi Y, Ueshima K, Chiba I, Segawa I, Kobayashi N, Saito M, Hiramori K. A new method using pulmonary gas-exchange kinetics to evaluate efficacy of beta-blocking agents in patients with dilated cardiomyopathy. Chest 2003; 124:954-61. [PMID: 12970023 DOI: 10.1378/chest.124.3.954] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND AND OBJECTIVES The effects of beta-blocking agents on exercise tolerance in cardiopulmonary exercise testing (CPX) have not been fully identified. Because the negative chronotropic effects of these agents produce a sluggish increase in heart rate (HR) during CPX, exercise capacity is actually underestimated by methods that depend on HR-related variables such as peak oxygen uptake (O(2)) and anaerobic threshold (AT). The aim of this study was to clarify the efficacy of beta-blocking agents by means of O(2) kinetics, a parameter independent of HR, in patients with dilated cardiomyopathy (DCM). DESIGN AND PATIENTS The exercise capacity of 12 patients (9 men and 3 women; mean +/- SD age, 54 +/- 12 years; New York Heart Association class I [n = 1], NYHA class 2 [n = 4], and NYHA class III [n = 6]) with DCM, who were treated with beta-blocking agents, was evaluated by CPX. O(2) was calculated from respiratory gas analysis on a breath-by-breath basis. Nine patients were treated with metoprolol (30 mg or 60 mg), two with carteolol (10 mg or 20 mg), and one patient with atenolol (25 mg). RESULTS All patients showed a significantly favorable results (ie, improvement in symptoms of congestive heart failure). Peak O(2) (20.4 +/- 5.1 to 18.8 +/- 5.8 mL/min/kg), AT (12.7 +/- 3.5 to 12.1 +/- 2.1 mL/min/kg), and exercise time (4.8 +/- 2.2 to 4.5 +/- 2.1 s) were unchanged. The time constant of O(2) kinetics (tau) on response to constant low-dose work loading (warm up) decreased significantly (64 +/- 30 to 44 +/- 24 s; p < 0.01) and ejection fraction increased (30 +/- 14 to 44 +/- 15%, p < 0.01) significantly following treatment with beta-blocking agents. In spite of excluding two NYHA I patients, these changes were also statistically correlated. CONCLUSION In the low level of exercise, tau was prolonged in patients with DCM. Although indexes of total exercise time and AT were not useful markers for clinical improvement in cardiac performance as assessed by echocardiography, measuring can validly assess the beneficial effects in heart failure treated with beta-blocking agents.
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Affiliation(s)
- Yasuyo Taniguchi
- Second Department of Internal Medicine, Iwate Medical University, Uchimaru 19-1, Morioka City, Iwate, Japan.
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Schalcher C, Rickli H, Brehm M, Weilenmann D, Oechslin E, Kiowski W, Brunner-La Rocca HP. Prolonged oxygen uptake kinetics during low-intensity exercise are related to poor prognosis in patients with mild-to-moderate congestive heart failure. Chest 2003; 124:580-6. [PMID: 12907546 DOI: 10.1378/chest.124.2.580] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVE To investigate the prognostic value of oxygen uptake (O(2)) kinetics during low-intensity exercise in patients with congestive heart failure. DESIGN Prospective cohort study. SETTING Tertiary care center. PATIENTS One hundred forty-six consecutive patients (128 men) with chronic heart failure, followed up for a mean (+/- SD) duration of 25 +/- 15 months. MEASUREMENTS A treadmill exercise test was performed with "breath by breath" gas-exchange monitoring. VO(2) kinetics were defined as the VO(2) deficit (ie, Delta VO(2) x time[rest to steady state] - Sigma VO(2)[rest to steady state]) and mean response time (MRT) [ie, VO(2) deficit/Delta VO(2)]. Cardiac death, urgent cardiac transplantation, and hospitalization due to worsening heart failure were considered as the end points. RESULTS Thirty patients (21%) died, 11 patients (8%) underwent urgent transplantation, and 32 patients (22%) were hospitalized. In univariate analysis, MRT was the most powerful predictor of survival, survival free of urgent transplantation, and survival free of hospitalization (hazard ratios [HRs] per 10 s, 1.65, 1.72, and 1.61, respectively; all p < 0.0001). The predictive value of MRT exceeded that of peak VO(2) (HR per mL/kg/min, 0.90; p = 0.02, 0.91; p = 0.007, and 0.95; p = 0.08, respectively). In multivariate analysis, MRT (HR per 10 s, 1.73; p = 0.0002), resting systolic BP (HR per 10 mm Hg, 0.65; p = 0.003), and the slope of the ventilatory response to exercise (HR per 10 U, 1.68; p = 0.02) were independent predictors of survival. CONCLUSIONS Our results suggest that VO(2) kinetics are strongly related to outcome in heart failure patients. Since it has several additional advantages over peak exercise testing (eg, less time-consuming, less demanding for the patients, less dependent on motivation, and applicable in patients with limitations other than cardiopulmonary disease), it has the potential to become a prognostic test for the assessment of heart failure patients.
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Affiliation(s)
- Christoph Schalcher
- Division of Cardiology, Department of Internal Medicine, University Hospital, Zurich, Switzerland
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Rickli H, Kiowski W, Brehm M, Weilenmann D, Schalcher C, Bernheim A, Oechslin E, Brunner-La Rocca HP. Combining low-intensity and maximal exercise test results improves prognostic prediction in chronic heart failure. J Am Coll Cardiol 2003; 42:116-22. [PMID: 12849670 DOI: 10.1016/s0735-1097(03)00502-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES This study investigated the combination of maximal and low-intensity exercise testing in predicting prognosis in chronic heart failure (CHF), using one single exercise test (two-step protocol). BACKGROUND Risk assessment based on any single factor has limited accuracy and reproducibility. METHODS Treadmill exercise testing was performed in 202 consecutive CHF patients (174 male; mean age 52 +/- 11 years) using "breath-by-breath" gas exchange monitoring. Oxygen uptake (VO(2)) kinetics were defined as oxygen deficit (DeltaVO(2) x time [rest to steady state] - Sigma VO(2) [rest to steady state]) and mean response time (MRT = oxygen-deficit/DeltaVO(2)). Peak VO(2) (VO(2)max) was defined as the highest VO(2). Mean follow-up was 873 +/- 628 days. The primary end point was cardiac mortality and the need for urgent heart transplantation. RESULTS Forty-four patients (22%) died and 15 (7%) were urgently transplanted. In both univariate and multivariate analyses, MRT >50 s was the most powerful predictor of the primary end point (hazard ratio [HR] 4.44), followed by predicted VO(2)max <50% (HR 3.50) and resting systolic blood pressure <105 mm Hg (HR 2.49, all p < 0.001). A majority (n = 130 [64%]) had one or none of these risk factors, with a one-year event rate of only 3%. Patients with two risk factors (n = 45 [22%]) were at medium risk (one-year event rate of 33%). Twenty-seven patients (13%) had all three risk factors, with a one-year event rate of 59%. The area under the curve, using the number of risk factors, was 0.86 +/- 0.04 for the primary end point at one year. These results were independent of medication, in particular, beta-blockade. CONCLUSIONS A combination of low-intensity and maximal exercise test results improves assessment of prognosis in patients with CHF.
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Affiliation(s)
- Hans Rickli
- Division of Cardiology, Department of Internal Medicine, University Hospital, Zürich, Switzerland
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Behnke BJ, McDonough P, Musch TI, Poole DC, Arena R. Comparison of oxygen uptake on-kinetics calculations in heart failure. Med Sci Sports Exerc 2003; 35:708-9; author reply 709. [PMID: 12673159 DOI: 10.1249/01.mss.0000058444.43322.05] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jourdain P, Funck F, Bellorini M, Guillard N, Loiret J, Thebault B, Desnos M, Duboc D. Bedside B-type natriuretic peptide and functional capacity in chronic heart failure. Eur J Heart Fail 2003; 5:155-60. [PMID: 12644005 DOI: 10.1016/s1388-9842(02)00247-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES To determine if B-type natriuretic peptide (BNP) measurement could be useful in determination of functional capacity in patients suffering from chronic heart failure. BACKGROUND Evaluating functional capacity is a crucial factor in the follow-up of patients with chronic heart failure. There are numerous methods for measuring functional capacity and their relative merits remain under discussion. Clinical classifications are very subjective and other methods are difficult to use in clinical practice. METHODS We evaluated functional capacity in 151 consecutive patients using the 6-min walk test. All patients were clinically classified using the New York Heart Association (NYHA) classification. We measured BNP plasma levels using a bedside BNP test. RESULTS Six minute walk test performance decreased through NYHA classes 1 to 4 (469+/-87, 411+/-82, 325+/-83 and 196+/-63 m, respectively, P<0.01) and BNP levels increased through NYHA classes 1 to 4 (26.3+/-7.2, 73+/-13, 401+/-74 and 924+/-84 pg/ml, respectively, P<0.001). There was a significant correlation between 6-min walk test performance and BNP plasma levels (R=0.69 P<0.001) and a weaker correlation between BNP and left ventricular ejection fraction (R=0.45 P<0.04). In some patients there was a mismatch between NYHA classification and 6-min walk test performance. In all cases BNP could correct the clinical estimation of functional capacity. When we divided the patients into three sub-groups within each NYHA class, we showed that using BNP could better define functional capacity in patients suffering from chronic heart failure in NYHA classes I to III. CONCLUSION The measurement of BNP levels thus usefully supplements the clinical examination. The existence of bedside BNP testing methods facilitates its use in routine clinical practice. It also permits easier follow-up of patients with chronic heart failure.
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Affiliation(s)
- P Jourdain
- Service de Cardiologie Centre Hospitalier René Dubos, 6 avenue d'Ile de France 95300, Pontoise, France.
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Scharf C, Merz T, Kiowski W, Oechslin E, Schalcher C, Brunner-La Rocca HP. Noninvasive assessment of cardiac pumping capacity during exercise predicts prognosis in patients with congestive heart failure. Chest 2002; 122:1333-9. [PMID: 12377861 DOI: 10.1378/chest.122.4.1333] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Prognostic parameters in patients with congestive heart failure (CHF) are important for guiding therapeutic options. Maximal oxygen uptake (O(2)max) is a widely used parameter for prognostic assessment in patients with CHF and correlates with exercise cardiac output; however, afterload is not taken into account. METHODS The concept of a noninvasive surrogate of cardiac power output combines exercise systolic BP (SBP), as an estimate of afterload, with O(2)max, as an estimate of exercise cardiac output neglecting preload. Thus, a variable termed exercise cardiac power (ECP) is defined as the product of O(2)max (expressed as a percent predicted value) and SBP (ECP, expressed as %mm Hg, is the product of O(2)max, expressed as percentage of predicted maximum, times systolic pressure. The prognostic value of ECP obtained during routine treadmill ergospirometry was assessed in patients referred to our heart failure clinic. Patients undergoing heart transplantation were censored at the time of transplantation. RESULTS One hundred fifty-four patients were followed prospectively for a mean (+/- SE) duration of 625 +/- 32 days. Thirty-two patients (21%) died. ECP was the most powerful predictor of mortality, was the combined end point of mortality or hospitalization for worsening heart failure (all p < 0.001), and was an independent predictor in multivariate analysis. An ECP of < 5,000 %mm Hg indicated a poor prognosis with a 1-year mortality rate of 37%, whereas only 2% of the patients having an ECP of > 9,000 %mm Hg died during the first year. CONCLUSION The integration of afterload and O(2)max improves the prognostic value of each indicator, and provides an easily available and independent predictor of mortality and morbidity in CHF patients. This integrative concept of cardiac hydraulic performance is superior to O(2)max and can be used in routine ergospirometry.
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Affiliation(s)
- Christoph Scharf
- Heart Failure and Cardiac Transplantation Unit, Division of Cardiology, University Hospital of Zürich, Zürich, Switzerland.
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Arena R, Humphrey R, Peberdy MA, Madigan M. Comparison of oxygen uptake on-kinetic calculations in heart failure. Med Sci Sports Exerc 2002; 34:1563-9. [PMID: 12370556 DOI: 10.1097/00005768-200210000-00006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The analysis of oxygen (O(2)) uptake on-kinetics during steady-rate is gaining interest in the heart failure (HF) population. The rate change in O(2) at the initiation of exercise can be assessed via nonlinear regression time constant (TC) or an algebraic equation (mean response time [MRT]). These calculations are presumed to be interchangeable, but research supporting this claim is limited. This investigation compares and contrasts two of the more commonly used O(2) uptake on-kinetic calculations. METHOD Twenty-eight subjects diagnosed with compensated HF and 19 age, sex, and activity-matched controls underwent a symptom-limited exercise test and a steady-rate exercise session (6 min). Peak O(2) uptake, O(2) uptake at ventilatory threshold, the O(2) uptake TC (TC), and the O(2) uptake mean response time (MRT) were calculated for each subject. RESULTS O(2) uptake on-kinetics was significantly faster for the control group ( < 0.05) regardless of calculation method. There was a significant difference between the O(2) uptake TC and MRT for the HF group. All O(2) uptake on-kinetic calculations were significantly correlated with aerobic capacity. CONCLUSIONS O(2) uptake TC and MRT values may not be interchangeable in the HF population. All O(2) uptake on-kinetic calculations did produce a significant difference between experimental and control groups and correlated with indicators of aerobic capacity. The 10-s O(2) uptake on-kinetic calculations may be preferable secondary to expired gas fluctuations associated with breath-by-breath measures. Further work is, however, needed to determine which averaged O(2) uptake on-kinetic expression is optimal given the significant difference between TC and MRT. A mechanism for this difference may be the oscillatory ventilatory expired gas pattern demonstrated by some patients with HF.
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Affiliation(s)
- Ross Arena
- Department of Physical Therapy, Virginia Commonwealth University, Medical College of Virginia, Health Sciences Campus, Richmond, VA, USA
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Arena R, Humphrey R, Peberdy MA. Measurement of oxygen consumption on-kinetics during exercise: implications for patients with heart failure. J Card Fail 2001; 7:302-10. [PMID: 11782852 DOI: 10.1054/jcaf.2001.27666] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Oxygen consumption (VO(2)) on-kinetics describes the rate change in oxygen uptake at the initiation of exercise. Several mathematical and graphical methods are used to assess VO(2) on-kinetics during constant-load or progressive exercise. VO(2) on-kinetics is prolonged in patients with heart failure (HF) compared with individuals who have normal cardiopulmonary function. Cardiac function has been implicated as one of the controlling mechanism for this observation. The contribution that pulmonary, vascular, and skeletal muscle function makes to delayed VO(2) on-kinetics in HF has yet to be determined. VO(2) on-kinetics also appears to have clinical value in HF, although evidence supporting this claim is limited. Questions about the controlling mechanism(s) and practical application of VO(2) on-kinetics in HF therefore remain unanswered. This report provides an overview of VO(2) on-kinetics assessment techniques, reviews research pertaining to the HF population, and provides direction for future investigations.
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Affiliation(s)
- R Arena
- Department of Physical Therapy, New York University, New York, NY 10010, USA
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Lauer MS, Snader CE. Using exercise testing to prognosticate patients with heart failure. Which parameter should we measure? Cardiol Clin 2001; 19:573-81. [PMID: 11715178 DOI: 10.1016/s0733-8651(05)70244-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Peak oxygen consumption, as measured by direct gas exchange analysis during exercise testing, is well established as a powerful and independent predictor of risk for death among patients with chronic, but stable, heart failure. Although there is still some debate about whether peak oxygen consumption should be indexed against a predicted value and what the best cut-off point may be, most authorities agree that peak oxygen consumption is such a powerful predictor of outcome that it routinely should be incorporated into the evaluation of all ambulatory heart transplant candidates. A few recent studies have demonstrated that a hyperventilatory response to exercise, as measured by the VE/VCO2 slope, also may be a powerful and independent predictor of death; however, more large studies, with large numbers of end-points, will be needed before this measure can deservedly take a place alongside peak oxygen consumption as a primary component of the heart failure staging process.
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Affiliation(s)
- M S Lauer
- Department of Cardiology, Cleveland Clinic Foundation, Cleveland, Ohio, USA.
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M'Bouh S, Bellmont S, Lampert E, Epailly E, Zoll J, N'Guessan B, Ribera F, Geny B, Oyono S, Arnold P, Lonsdorfer J, Mettauer B. An impaired cardiodynamic phase contributes to the abnormal VO(2) kinetics at exercise onset in both congestive heart failure and heart transplant patients but results from differing mechanisms. Transplant Proc 2001; 33:3543-5. [PMID: 11750508 DOI: 10.1016/s0041-1345(01)02426-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- S M'Bouh
- Department of Physiology, Faculty of Medicine, Strasbourg, France
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MacDonald MJ, Naylor HL, Tschakovsky ME, Hughson RL. Peripheral circulatory factors limit rate of increase in muscle O(2) uptake at onset of heavy exercise. J Appl Physiol (1985) 2001; 90:83-9. [PMID: 11133896 DOI: 10.1152/jappl.2001.90.1.83] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We used an exercise paradigm with repeated bouts of heavy forearm exercise to test the hypothesis that alterations in local acid-base environment that remain after the first exercise result in greater blood flow and O(2) delivery at the onset of the second bout of exercise. Two bouts of handgrip exercise at 75% peak workload were performed for 5 min, separated by 5 min of recovery. We continuously measured blood flow using Doppler ultrasound and sampled venous blood for O(2) content, PCO(2), pH, and lactate and potassium concentrations, and we calculated muscle O(2) uptake (VO(2)). Forearm blood flow was elevated before the second exercise compared with the first and remained higher during the first 30 s of exercise (234 +/- 18 vs. 187 +/- 4 ml/min, P < 0.05). Flow was not different at 5 min. Arteriovenous O(2) content difference was lower before the second bout (4.6 +/- 0.9 vs. 7.2 +/- 0.7 ml O(2)/dl) and higher by 30 s of exercise (11.2 +/- 0.7 vs. 10.8 +/- 0.7 ml O(2)/dl, P < 0. 05). Muscle VO(2) was unchanged before the start of exercise but was elevated during the first 30 s of the transition to the second exercise bout (26.0 +/- 2.1 vs. 20.0 +/- 0.9 ml/min, P < 0.05). Changes in venous blood PCO(2), pH, and lactate concentration were consistent with reduced reliance on anaerobic glycolysis at the onset of the second exercise bout. These data show that limitations of muscle blood flow can restrict the adaptation of oxidative metabolism at the onset of heavy muscular exertion.
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Affiliation(s)
- M J MacDonald
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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Rickli H, Brunner-La Rocca HP, Maccarter DJ, Duru F, Candinas R. Importance of AV synchronous pacing during low intensity exercise evaluated by oxygen kinetics. Pacing Clin Electrophysiol 2000; 23:174-9. [PMID: 10709225 DOI: 10.1111/j.1540-8159.2000.tb00798.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It has been shown that dual chamber pacing with preservation of AV synchrony (DDD) is superior to fixed rate ventricular (VVI) or rate responsive ventricular (VVIR) pacing modes, as evaluated by ventilatory response to exercise. Previous studies have focused on the benefits of maintained AV synchrony at maximal exercise. However, there are limited data comparing O2 kinetics in different pacing modes during low intensity exercise, representing the majority of daily activities. This study aimed to provide an evaluation of different pacing modes using O2 kinetics during low intensity exercise. Nineteen patients (age 61 +/- 18 years) with complete AV block underwent low intensity treadmill exercise (35 W) with simultaneous evaluation of symptoms and O2 kinetics in three pacing modes. The first test was performed in DDD mode followed by a second test in VVIR mode with a programmed heart rate corresponding to the sinus rate during the first test. After 6 minutes of each test, the mode was switched from DDD to VVIR and vice versa. The third test was performed in VVI mode at 70 beats/min. O2 kinetics were defined as O2 deficit (time [rest to steady state] x delta VO2-sigma VO2 [rest to steady state]) and mean response time (MRT) of oxygen consumption (O2 deficit/delta VO2). The O2 deficit was 551 +/- 134 mL in DDD pacing, 634 +/- 139 mL in VVIR pacing, and 648 +/- 179 mL in VVI pacing (P = 0.001). MRT was 49 +/- 7.8 seconds in DDD pacing, 54.7 +/- 9.5 seconds in VVIR pacing, and 57.4 +/- 11.0 seconds in VVI pacing (P = 0.002). Ten (53%) patients developed symptoms during switch from DDD to VVIR mode whereas the switch from VVIR to DDD mode was not perceived by any patient (P < 0.001). In conclusion, our study shows an impact of AV synchronous pacing and heart rate adaptation on O2 kinetics during low intensity exercise that correspond to casual daily life activities. Our observations may have clinical implications for the management of patients with complete AV block.
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Affiliation(s)
- H Rickli
- Division of Cardiology, University Hospital Zurich, Switzerland.
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