Reflex bradycardia during surgery.

Reflex bradycardia and sinus arrest may occur in a variety of surgical procedures, from neurosurgery to general abdominal, laparoscopic, ophthalmic and facial surgery and even procedures such as liver biopsies and electroconvulsive therapy. In most cases a vagally-mediated reflex has been implicated, although experimental support for this is often lacking. Drugs such as vecuronium, atracurium, halothane, fentanyl and succinylcholine may predispose to this reflex. Premedication with an anticholinergic is usually effective in preventing its occurrence.