Dinâmica da oxigenação muscular esquelética durante o exercício incremental em rampa com cicloergômetro em homens com insuficiência cardíaca e controles saudáveis

• Ano de defesa: 2019
• Autor(a) principal: Barroco, Adriano Candido [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Heart Failure; Exercise; Oxygen; Muscle; Near Infrared Spectroscopy; Insuficiência Cardíaca; Exercício; Oxigênio; Músculo; Espectroscopia De Raios Quasi-Infravermelhos
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=7688645; https://repositorio.unifesp.br/handle/11600/59230

In heart failure (HF), the balance between oxygen delivery-utilization (O2) is changed, thus decreasing exercise capacity. Near infrared spectroscopy (NIRS) is a technique that allows continuous and non-invasive monitoring of the peripheral muscle oxygenation during dynamic exercise. Specifically, the response time for the variation in deoxi-Hb+Mb ([Deoxi-Hb]), allows to evaluate the dynamic equilibrium between the delivery and O2 in the area analyzed. Investigations on muscular deoxygenation (or oxygen extraction) have been predominantly focused on the response to constant load exercise. In this context, the objective of this study was to investigate the relationship between delivery and microvascular use of O2 during ramp-incremental exercise in untrained adult patients with HF, in NYHA functional class II and III, compared with healthy individuals. In addition, we have proposed a practical approach to non-invasive evaluation of muscular deoxygenation during exercise. Ten patients with HF, with optimized clinical treatment (ejection fraction = 29.1±4.9%) and 10 age-matched controls were included in the study. The Δ[Deoxi-Hb] kinetic response was measured in the vastus lateralis muscle by NIRS. The Δ[Deoxi-Hb] sigmoid response pattern was less frequent in patients with HF. The slope of the [Deoxi-Hb] /ΔW (I) ratio was higher in patients with HF (2.2±1.3%), as compared to healthy controls (1.0±0.3 %). The O2 and the O2/W ratio were consistently smaller, and greater variations in [Deoxi-Hb] by the imposed load were also found in patients, as compared to controls. Therefore, these results indicate a substantial injury to the delivery-utilization balance of microvascular O2 during ramp-incremental exercise in patients with HF.