A method for testing for epinephrine-induced arrhythmias in rats.
Evaluation of a new inhaled anesthetic requires determination of the anesthetic's potential to predispose to ventricular (and other) arrhythmias in an animal model. This need poses logistic and economic burdens if the effects of large numbers of new anesthetics are to be surveyed. We have devised a technique for determining the potential of a new anesthetic to produce arrhythmias using a smaller animal (the rat) than previous methods. Our technique requires preliminary selection of male rats sensitive to the arrhythmias produced by the intravenous injection of epinephrine. Rats are tested after demonstrating the desired sensitivity. Using this model, rats given 1.4% halothane developed premature ventricular extrasystoles at a dose of 2.4 +/- 1.0 micrograms/kg epinephrine, and those receiving 1.6%-2.2% isoflurane at a dose of 28 +/- 24 micrograms/kg. This difference in dose requirements is about two to three times that in humans.