Evaluation of atrial fibrillation induced during anesthesia with fentanyl and pentobarbital in German Shepherd Dogs with inherited arrhythmias

Objective—To determine the type of atrial fibrillation induced by use of 2 pacing protocols during fentanyl and pentobarbital anesthesia before and after administration of atropine and to determine the organization of electrical activity in the left and right atria during atrial fibrillation in German Shepherd Dogs. Animals—7 German Shepherd Dogs. Procedures—Extrastimulus and pacedown protocols were performed before and after atropine administration. Monophasic action potential spectral entropy and mean dominant frequency were calculated during atrial fibrillation. Results—Atrial fibrillation occurred spontaneously in 6 of 7 dogs. All 7 dogs had atrial fibrillation induced. Sustained atrial fibrillation occurred in 13 of 25 (52%) episodes induced by the extrastimulus protocol and in 2 of 12 episodes of atrial fibrillation induced by pacedown. After atropine administration, sustained atrial fibrillation did not occur, and the duration of the nonsustained atrial fibrillation (6 episodes in 2 dogs of 1 to 26...