LEMAKALIM, A POTASSIUM CHANNEL AGONIST, REVERSES ELECTROPHYSIOLOGICAL IMPAIRMENTS INDUCED BY A LARGE DOSE OF BUPIVACAINE IN ANAESTHETIZED DOGS

We have examined the ability of lemakalim to correct bupivacaine-induced cardiac electrophysiological impairment in an experimental electrophysiological model in closed-chest dogs. Two groups (n = 6) of pentobarbitone-anaesthetized dogs were given atropine 0.2mg kg−1 i.v., and bupivacaine 4 mg kg−1 i.v. over 10 s. Group 2 received also lemakalim 0.03 mg kg−1 i.v. Bupivacaine induced bradycardia, prolonged PR and His-ventricle (HV) intervals, QRS duration, QTc and JTc intervals, decreased left ventricular (LV) dP/dt max and increased LV end-diastolic pressure. Lemakalim reversed bupivacaine-induced PR, HV, ORS, QTc and JTc prolongation, and did not worsen bupivacaine-induced bradycardia and haemo dynamic depression. We conclude that lemakalim can antagonize the main deleterious electrophysiological effects induced by a large dose of bupivacaine in anaesthetized dogs. (Br. J. Anaesth. 1993; 71: 534–539)