Thirty-day rhythmicity in electrocardiographic and electrolytic parameters in the athletic horse

Resumo

This paper describes circatrigintan progress of some electrocardiographic parameters and of the serum electrolytes in the jumper horse during a period of pre-competitive training performed in order to define the temporal organization of some parameters employed to evaluate the athletic performance of the horse. Five Sella Italiana horses, clinically healthy and specifically trained have been utilized for the study. All the subjects have undergone electrocardiographic recordings and blood sample takings by means of jugular venopuncture, at rest and always at the same hour, every five days for a period of one month. The following electrocardiographic parameters have been measured on individual ECG-recordings: P wave duration and amplitude, P-Q interval duration, QRS complex duration, R wave amplitude, T wave duration, S-T segment duration, Q-T interval duration, the longest and shortest R-R intervals; besides, mean R-R interval and D R-R, the highest, lowest and mean heart rate, have been calculated. The concentrations of magnesium, calcium, phosphorus and chlorine and of sodium and potassium have been determined on the blood samples, respectively by UV spectrophotometry and by flaming. The application of a statistic trigonometric model has permitted to point out the circatrigintan periodicity of the following electrocardiographic parameters: P wave duration, T wave duration, R wave amplitude, mean R-R interval and mean heart rate, and of the following serum electrolytes: sodium and magnesium. Based on these results, it is hypothesized that the cardiovascular system follows a “deterministic” progress with a “linear” variability systematically predictable within the temporal period considered.