A Canine Model of Sustained Atrial Fibrillation Induced by Rapid Atrial Pacing and Phenylephrine
Abstract:Atrial fibrillation is a common arrhythmia with considerable morbidity and mortality. Limitations in studying both the mechanisms and therapy of atrial fibrillation arise due to the paucity of models that yield sufficiently high-quality data, are not costly, and in which atrial fibrillation is sustained long enough to make the necessary observations. The canine model we present is based on the hypothesis that atrial fibrillation requires heterogeneity of repolarization, that distribution of vagal fibers is heterogeneous in the atria, and that atrial fibrillation will persist after reflex stimulation of vagal efferents by increased systemic arterial pressure. Dogs were anesthetized with morphine–chloralose because this combination maintains nearly intact autonomic control. Systemic arterial pressure was elevated approximately 75 mm Hg during infusion of phenylephrine (2 g/kg ˙ min−1). The right atrium was paced for 20 min at 40 Hz. Atrial fibrillation was sustained after cessation of atrial pacing in dogs receiving phenylephrine, but terminated within seconds in normotensive animals. In conclusion, atrial fibrillation can be maintained for at least 40 min after cessation of rapid atrial pacing in dogs with phenylephrine-induced hypertension.
Document Type: Research Article
Publication date: October 1, 2008
Comparative Medicine (CM), an international journal of comparative and experimental medicine, is the leading English-language publication in the field and is ranked by the Science Citation Index in the upper third of all scientific journals. The mission of CM is to disseminate high-quality, peer-reviewed information that expands biomedical knowledge and promotes human and animal health through the study of laboratory animal disease, animal models of disease, and basic biologic mechanisms related to disease in people and animals.
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