| Registro completo |
| Provedor de dados: |
BJMBR
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| País: |
Brazil
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| Título: |
A practical approach to assess leg muscle oxygenation during ramp-incremental cycle ergometry in heart failure
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| Autores: |
Barroco,A.C.
Sperandio,P.A.
Reis,M.
Almeida,D.R.
Neder,J.A.
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| Data: |
2017-01-01
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| Ano: |
2017
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| Palavras-chave: |
Heart failure
Exercise
Oxygen
Muscle
Near-infrared spectroscopy
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| Resumo: |
Heart failure is characterized by the inability of the cardiovascular system to maintain oxygen (O2) delivery (i.e., muscle blood flow in non-hypoxemic patients) to meet O2 demands. The resulting increase in fractional O2 extraction can be non-invasively tracked by deoxygenated hemoglobin concentration (deoxi-Hb) as measured by near-infrared spectroscopy (NIRS). We aimed to establish a simplified approach to extract deoxi-Hb-based indices of impaired muscle O2 delivery during rapidly-incrementing exercise in heart failure. We continuously probed the right vastus lateralis muscle with continuous-wave NIRS during a ramp-incremental cardiopulmonary exercise test in 10 patients (left ventricular ejection fraction <35%) and 10 age-matched healthy males. Deoxi-Hb is reported as % of total response (onset to peak exercise) in relation to work rate. Patients showed lower maximum exercise capacity and O2 uptake-work rate than controls (P<0.05). The deoxi-Hb response profile as a function of work rate was S-shaped in all subjects, i.e., it presented three distinct phases. Increased muscle deoxygenation in patients compared to controls was demonstrated by: i) a steeper mid-exercise deoxi-Hb-work rate slope (2.2±1.3 vs 1.0±0.3% peak/W, respectively; P<0.05), and ii) late-exercise increase in deoxi-Hb, which contrasted with stable or decreasing deoxi-Hb in all controls. Steeper deoxi-Hb-work rate slope was associated with lower peak work rate in patients (r=–0.73; P=0.01). This simplified approach to deoxi-Hb interpretation might prove useful in clinical settings to quantify impairments in O2 delivery by NIRS during ramp-incremental exercise in individual heart failure patients.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2017001200603
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| Editor: |
Associação Brasileira de Divulgação Científica
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| Relação: |
10.1590/1414-431x20176327
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| Formato: |
text/html
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| Fonte: |
Brazilian Journal of Medical and Biological Research v.50 n.12 2017
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| Direitos: |
info:eu-repo/semantics/openAccess
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