Effects of sedation with detomidine hydrochloride on echocardiographic measurements of cardiac dimensions and indices of cardiac function in horses.

Twenty-six horses were sedated with detomidine hydrochloride (Domosedan, SmithKline Beecham Animal Health, Tadworth, Surrey, UK) at a dose of 10 micrograms/kg bwt, administered i.v. Echocardiograms were recorded before and after sedation, measurements of cardiac dimensions were made and functional indices were calculated. The pre- and post sedation values were compared. No significant change was detected following sedation in the ejection time (ET), left ventricular dimension, left atrial diameter at the sinotubular junction at end-systole or end-diastole or at the sinus of Valsalva at end-diastole. Sedation was found to result in a statistically significant increase in end-systolic left ventricular diameter and internal area and aortic diameter measured at the sinus of Valsalva. Left ventricular free-wall thickness and interventricular septal thickness at end-systole, fractional shortening, fractional area change and heart rate were significantly reduced following sedation. A significant increase in pre-ejection period (PEP), duration of electromechanical systole (EMS) and PEP/ET (ejection time) was detected.