Mechanism of hypotensive transients associated with abrupt bradycardias in conscious rabbits.

Background: Transient bradycardic hypotensive events occur in resting rabbits. If the hypotension is due to vasodepression, these events may be a model for vasovagal syncope.

Objectives: To determine whether these events are responses to brief stimuli and whether the hypotensive episodes are solely due to rapid-onset bradycardia.