Background: Vasopressin is an alternative drug to adrenaline in intractableventricular fibrillation. However, vasopressin can cause significant bradycardia, resulting in reducedcardiac output. We investigated whether pre-treatment with atropine abrogates vasopressin-induced bradycardiain a beating-heart canine model. Material/Methods: Five adult mongrel dogs received endotracheal vasopressin(1.0 U/kg) with or without endotracheal atropine (0.02 mg/kg) or a placebo (10 ml saline) after beinganesthetized and ventilated. Hemodynamic variables and arterial blood gases were determined. Each dog(studied 3 times, one week apart) served as its own control. Results: Endotracheal vasopressin producedearly and significant (p

Keywords: Administration, Inhalation, Atropine - pharmacology, Blood Pressure - drug effects, Bradycardia - prevention & control, Dogs, Heart Rate - drug effects, Intubation, Intratracheal, Vasopressins - administration & dosage