ECG Changes in Atropinized Dogs under Dexmedetomidine, Midazolam and Ketamine Anaesthesia

The study was conducted to evaluate the electrocardiographic changes in atropinized healthy female dogs undergoing Ovariohysterectomy. Atropine (0.04 mg kg⁻¹) followed 5 min later by dexmedetomidine (20μg kg⁻¹) IM were administered to all the 24 animals under study. The animals were randomly allotted to Groups D, DB and DP (n=8 per Group). Group D animals did not receive any opoids whereas, Groups DB and DP received butorphanol (0.1mg kg⁻¹) and pentazocine (3mg kg⁻¹) IM, respectively. After 10 min of premedication, anaesthesia was induced with midazolam (0.8 mg kg⁻¹) IV in all the groups and maintained with 1% ketamine as and when required. Although significant increase in PR and QT interval was observed at certain intervals but values were within the normal range and AV bock was prevented by pre-emptive administration of atropine. QRS complex duration and amplitude increased.