LAUSR

OBJECTIVE To investigate the effects of dexmedetomidine (DXM) and its subsequent reversal with atipamezole (APM) on the echocardiogram and circulating concentrations of cardiac biomarkers in cats. ANIMALS 14 healthy cats. PROCEDURES Cats underwent echocardiography and measurements of circulating cTn-I and NT-proBNP concentrations before (PRE) and during (INTRA) DXM sedation (40 µg/kg IM) and 2 to 4 (2H POST) and 24 (24H POST) hours after reversal with APM. RESULTS Administering DXM significantly decreased heart rate, right ventricular and left ventricular (LV) outflow tract velocities, and M-mode-derived LV free-wall thickness; increased LV end systolic diameter and volume; and caused valvar regurgitation. While sedative effects resolved within 25 minutes of APM reversal, the evolution of echocardiographic changes was mixed: LV ejection fraction and mitral valvar regurgitation score were different at 2H POST than at both INTRA and PRE (partial return toward baseline), LV end-diastolic volume was different PRE to INTRA and INTRA to 2H POST but not different PRE to 2H POST (full return toward baseline), and M-mode-derived LV free-wall thickness was significantly different from PRE to INTRA and PRE to 2H POST (no return toward baseline). Serum cTn-I and plasma NT-proBNP concentrations increased significantly with DXM, which remained significant 2H POST. CLINICAL RELEVANCE Administration of DXM and APM reversal produced changes in echocardiographic results and in circulating cTn-I and NT-proBNP concentrations. Understanding these changes could help veterinarians differentiate drug effects from cardiac disease.