Study on the frequency of cardiac dysrhythmias in apparently healthy horses of riding schools [Shiraz, Isfehan, and Tehran]

ABSTRACT

To find the frequency of cardiac dysrhythmiasin apparently healthy horses and discriminate functionalfrom pathological ones. Observational field study. The study was conducted on 544 horses but ECGwas recorded only from 395 cases. Data were evaluated by using analysisvariance and Chi-square. ECG was obtained on a base apex lead withthe paper speed of 25mm/sec and calibration of l0mm/mVat rest without restraining or using of tranquilizers. Thefindings were evaluated according to the criteria of normalcardiac rhythm. 102 out of 395 horses used for ECG recording hadsome types of cardiac arrhythmias [25.82%]. The mostfrequent dysrhythmias were heart block, sinus arrhythmiaand sinus tachycardia, respectively. Atrial fibrillation wasnot seen. This study showed that horses of ridingschools show cardiac dysrhythmias just like race horses.Major cardiac dysrhythmias are functional ones. Atrial andventricular premature beats should be cautiously looked.Furthermore, in contrast to what has been reported in theveterinary literature, no case of atrial fibrillation was seen.This dysrhythmia seems to be very rare among Iranianequine population for some unknown reasons