Effects of intravenous infusion of CaCl2 on the fibrillation thresholds in rabbits.

A study on the atrial and ventricular fibrillation thresholds performed in urethane anaesthetized rabbits showed that no significant change occurred until blood pressure was reduced to 40% of the initial value. Bilateral cervical vagotomy and the administration of propantheline did not affect these changes. (DL) propranolol (0.2 mg/kg i.v.) "unmasked" a tendency of CaCl2 to elevate the fibrillation threshold; it also increased the lethal calcium level.