The use of hyoscine N-butylbromide in anesthetic premedication of an equine with Mobitz II AV block

Abstract

Second-degree Mobitz II atrioventricular (AV) block, unlike the Mobitz I block, is characterized by presenting a normal PR interval before a non-conducted P wave and after this. Some blocks occur for physiological, metabolic, and structural causes, and due to the administration of α2-adrenergic medication. It has been recorded that most of the blocks and bradycardias are responsive to atropine or glycopyrrolate. This case report presents a five-year-old, male, quarter-mile race horse, referred to the Center for Veterinary and Animal Science at the Universidad CES for arthroscopy of his left carpus. After administering xylazine, diazepam, and ketamine to the patient in order to initiate the surgical procedure, the patient presents marked bradycardia (10 beats per minute). Therefore, it was decided to postpone the surgery. After his recovery from anesthesia, he is diagnosed with seconddegree Mobitz II AV block, which only responds to hyoscine N-butylbromide as treatment.