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A practical approach to assess leg muscle oxygenation during ramp-incremental cycle ergometry in heart failure
Barroco, AC; Sperandio, PA; Reis, M; Almeida, D R; Neder, JA.
  • Barroco, AC; Disciplina de Cardiologia, Universidade Federal de São Paulo. Setor de Fisiologia Clínica do Exercício, Disciplina de Pneumologia, Universidade Federal de São Paulo. São Paulo. BR
  • Sperandio, PA; Disciplina de Cardiologia, Universidade Federal de São Paulo. Departamento de Cardiologia, Instituto Dante Pazzanese de Cardiologia. Setor de Fisiologia Clínica do Exercício, Disciplina de Pneumologia, Universidade Federal de São Paulo. São Paulo. BR
  • Reis, M; Departamento de Fisioterapia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro. Rio de Janeiro. BR
  • Almeida, D R; Disciplina de Cardiologia, Universidade Federal de São Paulo. São Paulo. BR
  • Neder, JA; Laboratory of Clinical Exercise Physiology, Division of Respiratory and Critical Care Medicine, Queen's University. Disciplina de Cardiologia, Universidade Federal de São Paulo. São Paulo. BR
Braz. j. med. biol. res ; 50(12): 6327, 2017. tab, graf
Article in English | LILACS, SES-SP, SESSP-IDPCPROD, SES-SP | ID: biblio-888973
ABSTRACT
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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Full text: Available Index: LILACS (Americas) Main subject: Oxygen Consumption / Hemoglobins / Muscle, Skeletal / Heart Failure / Leg Type of study: Observational study / Risk factors Limits: Humans / Male Language: English Journal: Braz. j. med. biol. res Year: 2017 Type: Article Institution/Affiliation country: Departamento de Fisioterapia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro/BR / Disciplina de Cardiologia, Universidade Federal de São Paulo/BR / Laboratory of Clinical Exercise Physiology, Division of Respiratory and Critical Care Medicine, Queen's University/BR

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Full text: Available Index: LILACS (Americas) Main subject: Oxygen Consumption / Hemoglobins / Muscle, Skeletal / Heart Failure / Leg Type of study: Observational study / Risk factors Limits: Humans / Male Language: English Journal: Braz. j. med. biol. res Year: 2017 Type: Article Institution/Affiliation country: Departamento de Fisioterapia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro/BR / Disciplina de Cardiologia, Universidade Federal de São Paulo/BR / Laboratory of Clinical Exercise Physiology, Division of Respiratory and Critical Care Medicine, Queen's University/BR