Dg. Michaloudis et al., THE EFFECTS OF MIDAZOLAM FOLLOWED BY ADMINISTRATION OF EITHER VECURONIUM OR ATRACURIUM ON THE QT INTERVAL IN HUMANS, European journal of anaesthesiology, 12(6), 1995, pp. 577-583
Prolongation of the QT interval may produce potentially hazardous dysr
hythmias. The effects on the QT interval of midazolam followed by admi
nistration of either vecuronium or atracurium have been investigated.
Thirty patients, ASA I or II, without cardiovascular problems, electro
lyte abnormalities or receiving any medication were studied. All patie
nts were premedicated with midazolam 0.08 mg kg(-1) i.m. 30-60 min bef
ore surgery. Anaesthesia was induced with midazolam 0.4 mg kg(-1). ECG
recordings as well as heart rate and arterial pressure measurements w
ere obtained before induction of anaesthesia and 1, 3 and 5 min after
midazolam administration. Further recordings were obtained at 1,3 and
5 min after either vecuronium 0.1 mg kg(-1) (15 patients) or atracuriu
m 0.5 mg kg(-1) (15 patients). Further recordings were obtained immedi
ately after tracheal intubation and at 1, 3 and 5 min later. Midazolam
followed by administration of either vecuronium or atracurium did not
produce any significant change in QT(c) interval (QT interval correct
ed for heart rate). Statistically sig significant prolongation of QT,w
as observed in both groups after intubation, although the mean QT(c) v
alues did not exceed the upper limits of normal. Heart rate and arteri
al pressure were also increased significantly in both groups after int
ubation.