Effect of atropine on bradydysrhythmias induced by succinylcholine following pretreatment with D-tubocurarine.

This study was designed to compare the effectiveness of pretreatment with the combination of d-tubocurarine and atropine with d-tubocurarine alone in preventing changes in cardiac rate and rhythm following repeated administration of succinylcholine. Sixty subjects were randomly divided into three groups of twenty. Group one received d-tubocurarine 0.04 mg.kg-1 and atropine 0.01 mg.kg-1, and group two d-tubocurarine 0.04 mg.kg-1 only, given three minutes before induction of anaesthesia. Group three received no pretreatment. Immediately following thiopentone induction succinylcholine 1 mg.kg-1 was given to all patients. A further dose of succinylcholine 1 mg.kg-1 was given to patients in the pretreatment groups following recovery of neuro-muscular function. Both pretreatment groups showed a small statistically significant fall in mean heart rate after the second dose of succinylcholine. One patient in each pretreatment group showed a fall in heart rate to less than 50 beats min-1; two patients in the group who received both d-tubocurarine and atropine, and three patients in the d-tubocurarine only group, showed a fall in heart rate of 25 per cent or more. It is concluded that the addition of atropine may be unnecessary for prevention of succinylcholine-induced bradydysrhythmias when d-tubocurarine pretreatment is given.