[The effect of age and training on the ECG time curve of purebred horses]

In 246 horses of the English Thoroughbred breed of several age categories, divided into four test populations, the influence was studied of age and training on the pulse rate and time intervals of ECG (PQ, QRS, QT and QTc). It was found that with the increasing age and training action slowed down gradually. Duration of the atrioventricular path (PQ) is prolonged, time of ventricular activation (QRS) and time of the electrical systole (QT) including its value corrected according to the actual pulse rate (QTC). In this way the origin of the so called sports electrocardiogram in trained race horses is characterized.