Bradycardia and cardiac asystole following a single injection of suxamethonium

Twenty cases of severe bradycardia, including 12 cases of cardiac asystole, following administration of a single dose of suxamethonium to 17 adult patients are presented. Treatment consisted of i.v. atropine in 16 cases, and in four cases external cardiac massage or a precordial thump was also given. Remission was complete in all cases. The mechanism is not known, but it is suggested that i.v. administration of fentanyl at induction may enhance the tendency to bradycardia following suxamethonium. Absence of preoperative atropine may also be of importance.