Physical and electrocardiographic evaluation of horses used for wagon traction

The objective of this research was to evaluate the electrocardiogram ( ECG) of horses used for wagon traction and to compare the results with the parameters obtained from inactive horses or horses submitted to a training routine. Fifty-six 3-15-year-old healthy horses (22 females and 34 males) were divided into three groups: control (without a work routine; N= 21), wagon traction (N= 25) and athlete (N=10) and submitted to physical examination and ECG (at rest). The rhythm, heart rate (HR), amplitude and duration of ECG waveforms and intervals were obtained from the frontal plane and base-apex leads. Heart score (HS) was calculated using the arithmetic mean of QRS duration in LI, LII and LIII. Measurements of ECG waves were smaller in control group, in comparison with wagon traction and athlete groups, suggesting that exercise can change ECG. Similar results were observed in the wagon traction and athlete groups, but the electrophysiological adjustments to exercise were not the same for these groups.