This study aimed to investigate electrocardiographic changes in dogs aged 5 years or more submitted to two anesthetic combinations: atropine, levomeprazine, thiopental and halothane (ALTH), and atropine, tiletamine and zolazepam (ATZ). Forty dogs (24 males/16 females) weighing 5-24kg, were used. Dogs had no cardiac problems and were submitted to tartarectomy. All animals were submitted to two electrocardiograms (ECG), one before anesthesia and other immediately before surgery. The dogs were divided into two groups: group 1 received ALTH and group 2 received ATZ. Alterations in the ST segment, T wave, cardiac rhythm and a significant reduction of vagal tonus index were observed in both groups, but in group 2 a significant reduction of the PR and QT intervals and an increase in heart rate were also observed. These data suggest that the ALTH combination caused fewer changes in the ECG than the ATZ combination.
Dog; electrocardiogram; anaesthesia; tartarectomy