The Relationship between Cardiac Massage and Pupil Size in Cardiac Arrest in Dogs

When normal cardiac action in dogs was replaced by cardiac compression in the presence of aconitine-induced ventricular fibrillation, there was a 70% reduction in cardiac output. This low cardiac output was capable of constricting previously dilated pupils produced when ventricular fibrillation occurred, and hypoxic paralysis of the oculomotor nucleus is considered responsible for the pupillary dilatation.