ELECTROCARDIOGRAPHIC ALTERATIONS IN ANDALUSIAN HORSES ASSOCIATED WITHTRAINING

We studied training-related changes in the electrocardiograms of 16 An dalusian horses. The training schedule was carried out 5 days per week for 3 months. By Leads I, aVF and V-10 electrocardiograms were record ed at a chart speed of 25 mm/s and a sensitivity of 10 mm/mV. All reco rdings were obtained with the animal standing and at rest. We analyzed the morphology, duration and voltage of Q-, R-, S- and T-waves, the d uration of ST and TP segments and the QT interval, and the heart rate. The electrocardiographically observed alterations arising from traini ng included (a) changes in the polarity of the T-wave recorded with th e I and V-10 Leads from single-phase positive to negative; (b) changes in the morphology of the ventricular repolarization wave obtained wit h the aVF Lead (from single-phase negative to two-phase); (c) a decrea sed duration of the ventricular complex; (d) an increased duration of the electrical ventricular systole; (e) a decreased voltage for R- and Q-waves; (f) a diminished heart rate following training.