This study compared the heamodynamic effects of sufentanil with those observed following concomitant sufentanil and highdose vecuronium administration to determine whether vecuronium induces bradyarrhythmias. Sixty coronary artery bypass patients were stratified into beta blocker (n = 30) or non-beta blocker (n = 30) groups and following induction with sufentanil . Using a Holier ECG monitor, bradyarrhythmias were classified as mild , moderate [3-bloquds (n = 30) et non [3-bloquds (n = 30). Aprds l'induction au sufentanil (9 + 3 #g' kg -t) et midazolam (0,07 + 0,04 rag" kg-l), il~ refoivent soit de la succinylcholine 1 rag" kg -1 (SxCh), soit du vdcuronium 0,3 rag" kg -1 (Vec 0,3), soit du vdcuronium 0,5