Cardiac effects of succinyldicholine and succinylmonocholine.

The present study evaluated possible contribution of succinylmonocholine in producing serious cardiovascular effects with or without succinyldicholine, using albino rabbits as the experimental animal. Forty-eight experiments were performed, 22 in vivo and 26 in vitro (Langendort heart). Succinyldicholine and succinylmonocholine administered separately or together produced an immediate bradycardia in vivo as well as in vitro. The combination of these drugs had a direct arhythmogenic effect as well as an indirect reflux mediated cardiac effect. When succinyldicholine was given within five minutes following a dose of succinylmonocholine there was significant nodal and ventricular ectopic beats, but no bradycardia. Dysrhythmias in in vivo hearts were abolished by cord trans-section, trimethaphan and reserpine pretreatment. There was no evidence in vivo that succinylmonocholine produced more serious bradycardia, dysrhythmias or hypotension than succinyldicholine,