BRADYCARDIA DURING ANTAGONISM OF PANCURONIUM-INDUCED NEUROMUSCULAR BLOCK

Heart rate was compared in matched patients during antagonismof neuromuscular block induced by tubocurarine, pancuroniumor alcuronium with neostigmine 0.03 mg kg^–1 preceded byatropine 0.015 mg kg^–1. The frequency of bradycardia wasgreater during antagonism of pancuronium compared with alcuronium.Although there was a difference between the group receivingpancuronium and that receiving tubocurarine, it was not statisticallysignificant. The decrease in heart rate was more rapid and profoundin the pancuronium group; seven of the 15 patients who receivedpancuronium required an additional dose of atropine as comparedwith only one patient who received tubocurarine. However, thedifference in heart rate between those who received pancuroniumand those receiving tubocurarine was short-lasting, whereasthe heart rate of those who received alcuronium was higher thanthat in the other groups during the entire 60-min period ofobservation. The findings with pancuronium may be a result ofits inhibitory effect on serum cholinesterase.