The aim of this study was to evaluate to what extent the myocardial function in horses (measured by PW-tissue Doppler = PW-TDI) is affected during a sedation with
romifidine (0.04 mg/kg, i. v.), particularly in case of an accompanying
heart disease. Based on an echo- and electrocardiographic examination, a total of 45 horses was subdivided into group 1 (no
heart disease), group 2 (
heart disease without increased heart dimensions) and group 3 (
heart disease with increased heart dimensions). Heart rate (HF), M-mode- (FS%) and TDI-measurements were performed before and after the application of
romifidine. The velocities of the radial myocardial movement in the left and right ventricular wall were evaluated using PW-TDI. The TDI parameters included the isovolumic contraction (IVC), the systolic (S) as well as the early (E) and late diastolic maximal velocity (A). After the application of
romifidine HF and FS were significantly decreased in all groups. IVC, S and E, determined by PW-TDI were also significantly decreased in both ventricular walls. A significant difference between groups was shown for the isovolumic contraction in the left ventricular wall. This was observed distinctly more in horses with
heart disease and increased heart dimensions compared to horses with
heart disease but no increased heart dimensions. The results of the study indicate that PW-TDI is a suitable imaging technique to analyse the effects of
romifidine on equine myocardial function. The major percentage change after application of
romifidine for TDI measurements compared to the M-mode parameters indicate that the parameter myocardial velocity measured with TDI appeared to be the most sensitive parameter to document
romifidine--induced changes on the myocardium.