Respiratory oxygen cost for dead space challenge is characteristically increased during exercise in patients with chronic heart failure: Does it further decrease exercise capacity?

Kurotobi, Toshiya; Sato, Hideyuki; Yokoyama, Hiroshi; Li, Dan; Koretsune, Yukihiro; Ohnishi, Yozo; Karita, Michiko; Takeda, Hiroshi; Kuzuya, Tsunehiko; Hori, Masatsugu

doi:10.1016/s1071-9164(97)90014-2

Cited by 3 publications

(2 citation statements)

References 28 publications

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“…An increased workload demands higher oxygen consumption by inspiratory muscles (Collett et al ., 1985), which, in turn, will reduce energy efficiency of ventilation. Indeed, energy efficiency of ventilation is significantly reduced in most patients with HF and significantly correlates with exercise limitation and mortality (Al‐Rawas et al ., 1995; Kurotobi et al ., 1997; Wasserman et al ., 1997; Kleber et al . 2000; Meyer et al .…”

Section: Discussionmentioning

confidence: 99%

Levosimendan improves calcium sensitivity of diaphragm muscle fibres from a rat model of heart failure

Hees¹,

Acuña²,

Linkels³

et al. 2011

British J Pharmacology

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BACKGROUND AND PURPOSEDiaphragm muscle weakness occurs in patients with heart failure (HF) and is associated with exercise intolerance and increased mortality. Reduced sensitivity of diaphragm fibres to calcium contributes to diaphragm weakness in HF. Here we have investigated the ability of the calcium sensitizer levosimendan to restore the reduced calcium sensitivity of diaphragm fibres from rats with HF. EXPERIMENTAL APPROACHCoronary artery ligation in rats was used as an animal model for HF. Sham-operated rats served as controls. Fifteen weeks after induction of HF or sham operations animals were killed and muscle fibres were isolated from the diaphragm. Diaphragm fibres were skinned and activated with solutions containing incremental calcium concentrations and 10 mM levosimendan or vehicle (0.02% DMSO). Developed force was measured at each calcium concentration, and force-calcium concentration relationships were plotted. KEY RESULTSCalcium sensitivity of force generation was reduced in diaphragm muscle fibres from HF rats, compared with fibres from control rats (P < 0.01). Maximal force generation was~25% lower in HF diaphragm fibres than in control fibres (P < 0.05). Levosimendan significantly increased calcium sensitivity of force generation in diaphragm fibres from HF and control rats, without affecting maximal force generation. CONCLUSIONS AND IMPLICATIONSLevosimendan enhanced the force generating capacity of diaphragm fibres from HF rats by increasing the sensitivity of force generation to calcium concentration. These results provide strong support for testing the effect of calcium sensitizers on diaphragm muscle weakness in patients with HF.

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Section: Discussionmentioning

confidence: 99%

Levosimendan improves calcium sensitivity of diaphragm muscle fibres from a rat model of heart failure

Hees¹,

Acuña²,

Linkels³

et al. 2011

British J Pharmacology

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“…For more detailed information on methods of assessment please refer to the supplementary material. Oxygen cost of breathing was shown to be increased in women [236,237] and in obesity [238,239], post-operative patients [240], COPD [240,241], cystic fibrosis [242,243], children with asthma [244], sarcoidosis [245] and chronic heart failure [246,247]. In these conditions, the increased oxygen cost of breathing may contribute to increased energy cost during activities of daily living adding, particularly in diseases imposing a ventilator or cardiac constraint, an extra contribution to the reduced exercise capacity.…”

Section: Oxygen Cost Of Breathingmentioning

confidence: 99%

ERS statement on respiratory muscle testing at rest and during exercise

et al. 2019

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Assessing respiratory mechanics and muscle function is critical for both clinical practice and research purposes. Several methodological developments over the past two decades have enhanced our understanding of respiratory muscle function and responses to interventions across the spectrum of health and disease. They are especially useful in diagnosing, phenotyping and assessing treatment efficacy in patients with respiratory symptoms and neuromuscular diseases. Considerable research has been undertaken over the past 17 years, since the publication of the previous American Thoracic Society (ATS)/European Respiratory Society (ERS) statement on respiratory muscle testing in 2002. Key advances have been made in the field of mechanics of breathing, respiratory muscle neurophysiology (electromyography, electroencephalography and transcranial magnetic stimulation) and on respiratory muscle imaging (ultrasound, optoelectronic plethysmography and structured light plethysmography). Accordingly, this ERS task force reviewed the field of respiratory muscle testing in health and disease, with particular reference to data obtained since the previous ATS/ERS statement. It summarises the most recent scientific and methodological developments regarding respiratory mechanics and respiratory muscle assessment by addressing the validity, precision, reproducibility, prognostic value and responsiveness to interventions of various methods. A particular emphasis is placed on assessment during exercise, which is a useful condition to stress the respiratory system.

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Circulatory and Respiratory Response to Exercise With Added Respiratory Dead Space

Zatoń

Smolka

2011

Human Movement

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Respiratory oxygen cost for dead space challenge is characteristically increased during exercise in patients with chronic heart failure: Does it further decrease exercise capacity?

Cited by 3 publications

References 28 publications

Levosimendan improves calcium sensitivity of diaphragm muscle fibres from a rat model of heart failure

Levosimendan improves calcium sensitivity of diaphragm muscle fibres from a rat model of heart failure

ERS statement on respiratory muscle testing at rest and during exercise

Circulatory and Respiratory Response to Exercise With Added Respiratory Dead Space

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