Physiological Values of P-Wave Dispersion in Silesian Breed Horses and Polish Primitive Horses

Electrocardiographic examinations were performed on 45 Silesian breed horses (group K, 3-16-year-old, 16 stallions, 29 mares) and on 25 Polish Primitive breed horses (group P, 1.5-19-year-old, two stallions, six geldings, 17 mares). Einthoven and chest leads were used. P-wave dispersion was electronically evaluated. There was no correlation between P-wave dispersion and other ECG parameters, age, sex, body mass, or month of pregnancy. The average value of P-wave dispersion for all horses was 30.77 ms (SD 3.92 ms), however in particular groups it was: in group P - 31.89 ms (SD 3.07 ms), and in group K - 30.15 ms (SD 4.27 ms). The maximum value of P-wave dispersion in the studied population was 40 ms, in groups P and K - 37,6 ms and 40 ms, respectively. The physiological value of P-wave dispersion for the group of horses was below 45 ms.