Effects of xylazine and acepromazine on echocardiographic parameters in the healthy horse

Abstract

The aim of this study was to evaluate the effects of xylazine and acepromazine on the Doppler and M-mode echocardiography measurements in horses. Ten healthy crossbred horses were included in this study Baseline echocardiography was performed in all horses. Xylazine (0.5mg/kg IV) or acepromazine (0.01 mg/kg IV) was injected intravenously with a 4 week wash out period between drugs. Electrocardiogram was recorded simultaneously in the base-apex lead. The results showed that the heart rote in the xylazine group was significantly lower than in the control measurements (p = 0.021). In the xylazine group, there were 2nd degree atrioventricular blocks in two horses. The diameter of the left ventricle at the end of diastole (LVIDJ was decreased (p = 0.029) and the interventricular septum thickness at the end of diastole (IVSd) (p = 0.008) were increased in the xylazine group. Right ventricle internal diometer at the end of systole (RVIDJ were increased in both treatment groups. Our results showed that acepromazine and xylazine hove some detectable effects on echocardiographic measurements, but both the nature and the degree of these differences mean that they are unlikely to affect the diagnostic quality of the scan. Acepromazine at a dose of 0.01 mg/kg, used in horses undergoing echocardiographic examination, results in negligible changes in spectral and M-mode measurements.