Change in ECG parameters and cardiac indicators in aged racehorses

The aim of this paper was to study the characteristics of changes in ECG parameters and cardiac parameters in racehorses depending on age. Research was carried out on the basis of JSC "Pyatigorsk Hippodrome" and JSC "Tersk Pedigree Stud Farm No. 169" on 17 purebred English riding and Arabian race horses, which were divided into age groups: 2, 3 and 4 years old. All horses were in intensive hippodrome training. ECG was performed before and after work using a portable device "EK1T-03M2", in three standard and three reinforced limb leads, according to the method of R.M. Voskanyan modified by T.V. Ippolitova. The ECG was deciphered and the cardiac parameters were calculated according to generally accepted methods. It was found that in 2-year-old horses the processes of depolarization and repolarization in the atrial myocardium are weakened and intensified in the ventricular myocardium; compensated coronary artery disease and blockade are observed; all cardiac parameters decrease after exercise. In 3-year-old horses, the processes of depolarization and repolarization in the atrial myocardium intensify and weaken in the ventricular myocardium; uncompensated coronary artery disease, blockades are more often recorded; systolic functional indicators increase against the background of a decrease in diastolic. In 4-year-old horses, the tendency of changes in ECG and cardiac parameters, which appeared in 3-year-old horses, persists and intensifies. With age, racehorses increase overload, which leads to a weakening of the processes of excitation and recovery in the myocardium.