Echocardiographic evaluation of the cardiovascular effects of medetomidine, acepromazine and their combination in healthy dogs

The aim of this study was to compare the cardiovascular effects of medetomidine, acepromazine and their combination administered intravenously in healthy dogs. Ten dogs were included in this study and randomly assigned to the three different sedative protocols: medetomidine (2 μg/kg, protocol M), acepromazine (20 μg/kg, protocol A) and acepromazine followed by medetomidine with the same doses as above (protocol AM), in three different times. In all subjects before (Tbase) and 15 (T15), 50 (T50) and 80 (T80) minutes after the administration of the drugs, the following non-invasive measurements were obtained: blood pressure with oscillometric method, ECG, and echocardiography. Blood pressure and echocardiography evidenced decrease in left ventricular afterload secondary to acepromazine and an increase in right ventricular afterload due to medetomidine. The combination of the two drugs mitigated the effects expected by the single drugs used alone, and prevented the onset of atrioventricular blocks, such as seen in protocol M. The three protocols were eligible for sedation and premedication in healthy dogs. Moreover they had little impact on the echocardiographic variables evaluated in this study.