Pacemaker failure on induction of anaesthesia.

A patient with a permanent pacemaker presented for repair of a strangulated hernia. During induction of anaesthesia, the pacemaker generator stopped discharging, thus causing cardiac arrest. The likely cause of the generator failure was inhibition by suxamethonium-induced muscle fasciculations. Following defibrillation, and increase in stimulation threshold necessitated urgent insertion of a transvenous pacing system. It is suggested that, when suxamethonium is to be used in a patient with a permanent pacemaker, consideration should be given to reprogramming the pacemaker to asynchronous mode before induction of anaesthesia. If a patient with a pacemaker requires defibrillation, an acute increase in stimulation threshold may result and cause loss of capture. Rapid insertion of a transvenous pacing system may be necessary.