The electrocardiographic examination was performed in 33 training horses (2-16 years of age, 11 males and 22 females). Einthoven and precordial leads (I, II, III, aVR, aVL, aVF, CV1, CV2, CV4) were used. The ECG was performed in resting horses and immediately after exercise (10 min walk, 15 min trot, 10 min canter) using a portable Schiller AT-1 3-channel electrocardiograph, with a paper speed of 25 mm sec-1 and a sensitivity of 10 mm.mV-1. The heart rate, wave amplitudes, and duration time were estimated manually. All horses presented a significant increase in heart rate after exercise (rest 43.83 ±10.33 vs. exercise 73.2 ±14.8). QT intervals were significantly shortened in most of the leads. In resting horses, all P waves in the lead I were positive and almost all II, III and CV4 leads were positive. Simple negative P wave dominated in aVR and only simple negative T wave was found in the leads I. The biphasic shape was observed. After exercise, the amplitude of P and T waves rose, however, clear changes were not observed in wave polarisation and form. In the absence of specific racial characteristics of the electrocardiogram in the Polish Anglo- Arabians, electrocardiographic findings can be interpreted according to ECG standards adopted for horses.
1. Ayala I., Gutierrez C., Benedito J.L., Hernandez J., Castillo C., Lopez Alonso M., Miranda M., Montes A.: Morphology and amplitude values of the P and T waves in the electrocardiograms of spanish-bred horses of different ages. J Vet Med A 1999, 46, 225-230.
2. Ayala I., Gutierrez-Panizo C., Benedito J.L., Prieto F., Montes A.: Morphology and amplitude values of the electrocardiogram of Spanish-bred horses of different ages in the Dubois leeds system. Vet Res 2000, 31, 347-354.
3. Fregin G.F.: The equine electrocardiogram with standardized body and limb positions. Cornell Vet 1982, 72, 304-324.