Avaliação cardíaca de equinos submetidos ao condicionamento em esteira guiado pela concentração de lactato
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2023-05-08
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Universidade Estadual Paulista (Unesp)
Resumo
O remodelamento cardíaco que ocorre com o treinamento físico pode ser identificado pela ecocardiografia, a qual permite avaliar a morfologia e a função cardíaca. Objetivou-se avaliar em equinos, o efeito do condicionamento na velocidade correspondente à concentração de 2 mmol/L de lactato, sobre variáveis ecocardiográficas. Foram treinados durante seis semanas em esteira, 12 potros Puro Sangue Árabe (09 fêmeas e 03 machos castrados), com idade de 28,42 ± 3,75 meses e peso corporal de 312,17 ± 17,37 kg, com base na velocidade em que a concentração do lactato plasmático foi igual 2 mmol/L (V2), determinada em teste de exercício incremental (TEI). No mesmo teste, determinou-se a velocidade em que o lactato sanguíneo atingiu 4 mmol/L (V4). Foram realizadas ecocardiografias em repouso nos modos-B e M, Doppler pulsátil de fluxo e Doppler tecidual. A partir de medidas do modo M, foram calculadas a espessura média (EMP) e relativa (ERP) da parede livre do ventrículo esquerdo (VE), massa do VE (mVE), e as frações de encurtamento (FE) e de ejeção (FEj) do VE. As ecocardiografias foram realizadas antes (AT) e depois (DT) do período de treinamento físico, assim como o TEI para a determinação do nível de condicionamento. Empregaram-se o teste t para a comparação ao nível de 5% de significância e a análise por componentes principais (ACP). Todos os animais completaram o programa de condicionamento sem intercorrências. Houve aumento na V2 (AT: 5,2 ± 0,3; DT: 6,7 ± 0,4 m/s) e V4 (AT: 5,8 ± 0,4; DT: 7,6 ± 0,5 m/s) (p < 0,001). O diâmetro diastólico (AT: 9,11 ± 0,72; DT: 9,87 ± 0,75 cm) (p = 0,007), a massa (AT: 1.690,86 ± 372,64; DT: 1.886,90 ± 269,57 g) (p = 0,011) e o volume ejetado (VEj) (AT: 444,60 ± 129,62; DT: 538,40 ± 100,43 mL) (p = 0,042) do ventrículo esquerdo se elevaram. A parede livre do VE em diástole (PLVEd) (AT: 1,87 ± 0,27; DT: 1,84 ± 0,30 cm) e em sístole (PLVEs) (AT: 3,36 ± 0,22; DT: 3,40 ± 0,24 cm) não se modificou (p = 0,654) e (p = 0,617), respectivamente. A ACP reduziu a dimensionalidade de 24 variáveis selecionadas em sete componentes, os quais explicam 84% da variabilidade total. No componente um, o qual explica 22% da variabilidade total, as variáveis que apresentaram maior contribuição foram: átrio esquerdo (AE), débito cardíaco (DC), diâmetro interno do VE em diástole (DIVEd) e sístole (DIVEs), EMP, PLVEd, mVE, espessura do septo interventricular em diástole (SIVd), VEj, FEj, FE, velocidade máxima do enchimento ventricular inicial do fluxo transmitral (Emáx) e sua relação com a velocidade final (E:A). O protocolo de condicionamento empregado foi eficiente, pois melhorou a capacidade aeróbia dos animais. Ocorreu remodelamento cardíaco induzido principalmente pelo treinamento físico, com aumento da massa ventricular e do volume ejetado.
Physical training-induced cardiac remodeling can be identified by echocardiography in wich allows to evaluate the heart’s morphology and function. This study evaluated the effect of conditioning based on the velocity corresponding to a concentration of 2 mmol/L of lactate on echocardiographic measurements of horses. Twelve Purebred Arabians horses (09 filly and 03 geldings) with 28,42 ± 3,75 months old and body weight 312,17 ± 17,37 kg were trained during six weeks, based on the velocity wich plasmatic lactate concentration was 2 mmol/L (V2) determined in an incremental exercise test (IET). Also, the velocity that blood lactate reached 4 mmol/L (V4) was determined in the same test. Echocardiographic exams were performed at rest in the B and M-mode, pulsed Doppler, and tissue Doppler imaging. From M-measurements were calculated: the mean (MWT) and relative (RWT) free wall thickness of the left ventricle (LV), LV mass, fractional shortening (FS), and ejection fraction (EF) . The exams were performed before (BT) and after (AT) the physical training period as well as IET for conditioning level determination. The t-test was employed for comparison at a significance level of 5%, along with principal components analysis (PCA). All animals completed the training program with no intercurrence. The velocities increased V2 (BT: 5.2 ± 0.3; AT: 6.7 ± 0.4 m/s) e V4 (BT: 5.8 ± 0.4; AT: 7.6 ± 0.5 m/s) (p < 0.001). End-diastolic left ventricular internal diameter (LVIDd) (BT: 9.11 ± 0.72; AT: 9.87 ± 0.75 cm) (p = 0.007), LV mass (BT: 1690.86 ± 372.64; AT: 1886.90 ± 269.57 g) (p = 0.011), and stroke volume (SV) (BT: 444.60 ± 129.62; AT: 538.40 ± 100.43 mL) (p = 0.042) increased. There were no changes in left ventricular free wall at end-diastole (LVFWd) (BT: 1.87 ± 0.27; AT: 1.84 ± 0.30 cm) and end-systole (LVFWs) (BT: 3.36 ± 0.22; AT: 3.40 ± 0.24 cm) (p = 0.654) and (p = 0.617), respectively. The PCA reduced the dimensionality of 24 cardiac variables into seven components, which account for 84% of the total data variability. In component one, which explains 22% of the total variability, there was a greater contribution of left atrium (LA), cardiac output (CO), LVIDd, end-systolic left ventricular internal diameter (LVIDs), MWT, LVFWd, LV mass, end-diastolic interventricular septum thickness (IVSd), SV, EF, FS, the peak E wave (Emax) of the transmitral flow, and the Emax to Amax ratio (Emax:Amax). The conditioning protocol was effective to improve the aerobic capacity of the animals. There was cardiac remodeling induced mainly by physical training, with increase of left ventricular mass and stroke volume.
Physical training-induced cardiac remodeling can be identified by echocardiography in wich allows to evaluate the heart’s morphology and function. This study evaluated the effect of conditioning based on the velocity corresponding to a concentration of 2 mmol/L of lactate on echocardiographic measurements of horses. Twelve Purebred Arabians horses (09 filly and 03 geldings) with 28,42 ± 3,75 months old and body weight 312,17 ± 17,37 kg were trained during six weeks, based on the velocity wich plasmatic lactate concentration was 2 mmol/L (V2) determined in an incremental exercise test (IET). Also, the velocity that blood lactate reached 4 mmol/L (V4) was determined in the same test. Echocardiographic exams were performed at rest in the B and M-mode, pulsed Doppler, and tissue Doppler imaging. From M-measurements were calculated: the mean (MWT) and relative (RWT) free wall thickness of the left ventricle (LV), LV mass, fractional shortening (FS), and ejection fraction (EF) . The exams were performed before (BT) and after (AT) the physical training period as well as IET for conditioning level determination. The t-test was employed for comparison at a significance level of 5%, along with principal components analysis (PCA). All animals completed the training program with no intercurrence. The velocities increased V2 (BT: 5.2 ± 0.3; AT: 6.7 ± 0.4 m/s) e V4 (BT: 5.8 ± 0.4; AT: 7.6 ± 0.5 m/s) (p < 0.001). End-diastolic left ventricular internal diameter (LVIDd) (BT: 9.11 ± 0.72; AT: 9.87 ± 0.75 cm) (p = 0.007), LV mass (BT: 1690.86 ± 372.64; AT: 1886.90 ± 269.57 g) (p = 0.011), and stroke volume (SV) (BT: 444.60 ± 129.62; AT: 538.40 ± 100.43 mL) (p = 0.042) increased. There were no changes in left ventricular free wall at end-diastole (LVFWd) (BT: 1.87 ± 0.27; AT: 1.84 ± 0.30 cm) and end-systole (LVFWs) (BT: 3.36 ± 0.22; AT: 3.40 ± 0.24 cm) (p = 0.654) and (p = 0.617), respectively. The PCA reduced the dimensionality of 24 cardiac variables into seven components, which account for 84% of the total data variability. In component one, which explains 22% of the total variability, there was a greater contribution of left atrium (LA), cardiac output (CO), LVIDd, end-systolic left ventricular internal diameter (LVIDs), MWT, LVFWd, LV mass, end-diastolic interventricular septum thickness (IVSd), SV, EF, FS, the peak E wave (Emax) of the transmitral flow, and the Emax to Amax ratio (Emax:Amax). The conditioning protocol was effective to improve the aerobic capacity of the animals. There was cardiac remodeling induced mainly by physical training, with increase of left ventricular mass and stroke volume.
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Adaptação cardíaca, Cavalo, Ecocardiografia, Treinamento, Cardiac adaptation, Horses, Echocardiography, Training, Fisiologia animal