Dobutamine-induced bradycardia in a dog.

An otherwise healthy 8-year-old neutered male, mixed breed dog was anesthetized for surgical removal of multiple uroliths. Pre-anesthetic medication was midazolam, glycopyrrolate, and morphine. Anesthesia was induced with propofol and maintained with isoflurane in oxygen. One hour after induction, the patient moved and propofol was administered. Subsequently, the patient developed hypotension. Dobutamine administered at this time produced a rapid and profound decrease in heart rate that was treated successfully with atropine. The bradycardia in this case may be the result of the Bezold-Jarisch reflex, an intracardiac parasympathetic nervous reflex. Discontinuation of dobutamine and/or administration of a parasympatholytic drug should be performed if bradycardia occurs during dobutamine infusion.