Comparison of the effects of thiopentone and propofol on the electrocardiogram of dogs.
Sixty-four dogs were randomly assigned to receive either thiopentone or propofol and their electrocardiograms were recorded immediately before and shortly after they were anaesthetised. Thiopentone caused a marked increase in QT and JT intervals, a flattening of the T-wave and an increase in precordial QT dispersion. Propofol induced a less marked increase in QT and JT intervals, corrected for heart rate. Both agents induced an increase in heart rate and a decrease in heart rate variability, consistent with reduced vagal tone. Shortly after anaesthesia was induced, thiopentone affected ventricular repolarisation to a far greater extent than propofol, changes which suggest that it may be more likely to induce re-entrant ventricular arrhythmogenesis and could be associated with an increase in sympathetic tone. Propofol may therefore be more suitable than thiopentone for dogs with a susceptibility to ventricular arrhythmias or a long QT interval.
Dennis
S G
SG
Division of Small Animal Clinical Studies, Faculty of Veterinary Medicine, University of Glasgow Veterinary School, Bearsden Road, Bearsden, Glasgow, UK.
Wotton
P R
PR
Boswood
A
A
Flaherty
D
D
D000818:Animals; D004285:Dogs; D004562:Electrocardiography / Q000662:veterinary*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D015742:Propofol / Q000494:pharmacology*; D011897:Random Allocation; D012016:Reference Values; D013874:Thiopental / Q000494:pharmacology*; D013997:Time Factors
D006993:Hypnotics and Sedatives; D013874:Thiopental; D015742:Propofol