Efeitos do Condicionamento Sobre a Função Ventricular Esquerda de Equinos Jovens da Raça Puro Sangue Árabe

• Ano de defesa: 2023
• Autor(a) principal: Ramos, Gabriel Vieira [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Ecocardiografia; Esteira rolante; Testes de função cardíaca; Lactato; Treinamento
• Link de acesso: https://hdl.handle.net/11449/251231

Physical conditioning promotes changes in homeostasis that lead to significant metabolic alterations in various systems, including the cardiovascular system. In horses, several studies have evaluated protocols based on plasma lactate concentrations; however, few authors have analyzed their influence on cardiac function. This present study aims to investigate the adaptive responses to the left ventricular (LV) function of young horses, assessed at rest and immediately after a physical stress test (TStress), induced by six weeks of physical conditioning based on the external load necessary to achieve a plasma lactate concentration of 2 mmol/L (V2). Fourteen young Arabian Thoroughbred horses, with an average age of 28.42 ± 3.75 months and no prior history of physical conditioning, were used in this study. The animals were evaluated through echocardiography performed at rest and immediately after TStress, both before and after a six-week conditioning period based on V2 determined by an incremental exercise test (IET) on a treadmill. There was an improvement in the aerobic capacity of the animals, as evidenced by the increase in V2 (5.214 ± 0.328 vs. 6.763 ± 0.434) and V4 (5.857 ± 0.42 vs. 7.691 ± 0.549) (p <0.001) after the conditioning period. There were also reductions in resting heart rate (HR) and the maximum HR reached during TStress (p < 0.001). Conditioning led to a reduction in the internal diameter associated with increases in the thickness of the interventricular septum, posterior wall, average thickness, and LV mass (p < 0.05). The evaluation performed after TStress in conditioned animals revealed increases in integral time-velocity (ITV), stroke volume (SV), systolic indices (SI) and cardiac indices (CI), ejection times (ET) and deceleration times (DT), end-diastolic volume (EDV), time to the onset of radial myocardial velocity during the early diastolic phase (tEm), and time to maximum transmitral flow velocity (tEA), with reductions in preejection period (PEP) and PEP/ET ratios, circumferential velocity of myocardial fibers (Vcf). The conditioning protocol was capable of improving the aerobic capacity of the animals and promoting cardiac remodeling associated with improved left ventricular function.