[Peroperative sinus arrest in a patient with sick sinus syndrome (apropos of a case)]

A sinus arrest occured during a surgical intervention in a patient suffering from a sinus nodal dysfunction. The Fentanyl acetate used as an analgésic, seems to have played an important role in the genesis of the accident, depressing sinusal and junctional automatisms. Though unusual, this complication leads to a further investigation in preoperative period for a possible sinus nodal dysfunction in order to anticipate an extreme preoperative bradycardia (sino atrial block) treated with intravenous administration of isoprenaline. Intraveinous atropine test is a simple preoperative technique of research in front all unexplained sinus bradycardia.