Arrhythmias during Halothane Anesthesia I: The Influence of Atropine During Induction with Intubation

The changes in cardiac rhythm which occurred during induction of halothane‐N2O/O2 anesthesia with thiopenthal and one single dose of suxamethonium for intubation were studied in two groups of patients, one (at random) of which was given atropine intravenously 0.1 mg/10 kg 2 min before induction. There was a significantly higher incidence of arrhythmias in the atropine group (P < 0.01) ‐ including sinustachycardia ® 120 beats/min. The most common arrhythmias were supra ventricular ectopies. About half of those registered in the atropine group arose in direct connection with atropine administration. There was a relative accumulation of arrhythmias in connection with intubation in both groups. Ventricular ectopies were only observed during and immediately after intubation, and most often in the atropine group. The occurrence of arrhythmias was not age‐dependent. The cardioacceleration following intubation was significantly higher in the atropine group (P<0.01). No consistent changes in blood pressure as the result of the change in cardiac rhythm were observed in connection with the single arrhythmia episode or following atropine. On the other hand, no advantage could be seen in the use of the drug, and the cardioacceleration which is inherent in its action may be injurious to patients with a limited cardiac reserve.