Electrocardiographic parameters of Arabian horses submitted to prolonged exercise of endurance/Parametros eletrocardiograficos de equinos Puro Sangue Arabe submetidos a exercicio prolongado de enduro

• Published in: Ciência rural 2010-09, Vol.40 (9), p.1966
• Main Authors: Dumont, Cinthia Beatriz da Silva, Leite, Ceci Ribeiro, de Moraes, Julia Miranda, Alves, Rosangela de Oliveira, Godoy, Roberta de Ferro, de Lima, Eduardo Mauricio Mendes
• Format: Article
• Language: Spanish
• Subjects: Electrocardiogram; Electrocardiography; Heart beat; Physiological aspects
• ISSN: 0103-8478

Electrocardiographic parameters of 20 Thoroughbred Arabian horses were established at rest and after prolonged endurance exercise. The mean heart rate was 35. 85bpm at rest with predominant sinus rhythm, and 53.78bpm with sinus tachycardia after exercise. As physiological variation, wandering pacemaker was observed, and as non physiological, premature ventricular complex was noted. At post-exercise there was an increase of the amplitude of waves P, R, S and T, with P wave tending to become single in 35% of the animals and bifid positive in 65%, and with monophase positive T wave. There was a reduction in the duration of the waves, intervals and segments, and elongation of QTc, but the QRS complex hardly changed. The electrical axis in the frontal plane showed deviations to the right and to the left at rest, suggesting chamber enlargement and hypertrophy secondary to training, while after the exercise it showed extreme deviation to the right, indicating electrolyte imbalances. The average heart score was 128.45ms, which features the animals as athletes, being reduced to 118.60ms after exercise. Key words: electrocardiogram, equine, physiology of stress, endurance. Foram estabelecidos os parametros eletrocardiograficos de 20 equinos Puro Sangue Arabe em repouso e apos exercicio prolongado de enduro. A frequencia cardiaca media foi de 35,85bpm em repouso, com predominancia do ritmo sinusal, e de 53,78bpm, com taquicardia sinusal apos o exercicio. Como variacao fisiologica, observou-se marcapasso migratorio, e como nao fisiologica, complexo ventricular prematuro. No pos-exercicio, ocorreu aumento da amplitude das ondas P, R, S e T, com onda P tendendo a se tornar unica em 35% dos animais e bifida positiva em 65%, e a onda T monofasica positiva. Houve reducao da duracao das ondas, dos intervalos e dos segmentos, e alongamento do QTc; porem, o complexo QRS quase nao se alterou. O eixo eletrico, no plano frontal, apresentou desvios a direita e a esquerda em repouso sugestivo de aumento de camara e hipertrofia secundarias ao treinamento, ao passo que, apos o exercicio, demonstrou desvio extremo para a direita, indicando alteracoes eletroliticas. O escore cardiaco medio foi de 128,45ms, o que caracteriza os animais como atletas, sendo reduzido a 118,60ms apos o exercicio. Palavras-chave: eletrocardiograma, equino, fisiologia do esforco, enduro.