Dexmedetomidine in Healthy Dogs: Impact on Electrocardiographic Parameters

Objective: To evaluate whether intravenous administration of dexmedetomidine alters the electrocardiographic parameters of healthy dogs. Animals: 22 healthy dogs. Study Design: prospective blind clinical trial. Materials and Methods: The dogs underwent electrocardiographic monitoring at two moments: baseline moment (MB), subjected to tranquilization with butorphanol (0.25 mg/kg/IM), and dexmedetomidine moment (MDEX), after 10 min of intravenous administration of dexmedetomidine (bolus of 2 μg/kg, in 2 minutes, followed by continuous infusion at a rate of 2 μg/kg/hour). Results: After intravenous administration of dexmedetomidine, sinus bradycardia predominated. Regarding electrocardiographic parameters, there was a significant increase in the duration of the P wave (44; 51 ms), QRS complex (62; 67 ms), PR interval (95; 126 ms), and QT interval (207; 252 ms) and reduction in the QTc interval (249; 226 ms), without significant change in systolic, mean, and diastolic blood pressure. Conclusion: Intravenous administration of dexmedetomidine in healthy dogs results in increased parasympathetic tone with significant reduction in heart rate and increased conduction time of electrical impulses in the myocardium.