Carotid sinus baroreceptors are located cephalad to the bifurcation of the common carotid artery. Manipulation of carotid sinus during carotid surgery activates the carotid sinus reflex by stimulating the carotid sinus baroreceptors, which give rise to impulse carried via glossopharyngeal nerve to the medulla oblongata. These afferent impulses lead to the activation the cardiac vagal efferent nerve fibers, leading to cardiac bradycardia, AV block, or even cardiac arrest. Pronounced or sustained symptoms caused by this carotid sinus reflex should be treated promptly with cessation of surgical manipulation and atropine. Infiltration of the carotid sinus with local anesthetic, e.g. 1% lidocaine can be used to prevent these episodes. However, the infiltration itself can activate the reflex and leads to bradycardia.