Epinephrine-induced premature ventricular contractions and changes in arterial blood pressure and heart rate during I-653, isoflurane, and halothane anesthesia in swine.

I653 is a new inhalation anesthetic having especially desirable recovery characteristics because of its very low blood and tissue solubility. Investigations of its cardiovascular and electroencephalographic effects have revealed actions similar to those of isoflurane. However, these studies did not evaluate the potential of I653 to predispose the heart to epinephrine-induced arrhythmias. In this investigation, we studied eight domestic swine to compare the effects of I653 with those of other anesthetics on the cardiac arrhythmogenic actions of intravenously infused epinephrine. I653, isoflurane, and halothane each were given, on separate days, at 0.7-0.8 and at 1.1-1.2 MAC. The rate of infusion of epinephrine needed to produce premature ventricular contractions (PVCs) when the animals were anesthetized with I653 (6.9 +/- 0.7 and 6.6 +/- 0.9 micrograms.kg-1.min-1 at 0.8 and 1.2 MAC) did not differ from that during isoflurane anesthesia (5.7 +/- 1.1 and 6.0 +/- 1.0 micrograms.kg-1.min-1 at 0.7 and 1.1 MAC), but was greater than that required during halothane anesthesia (1.3 +/- 0.2 and 1.1 +/- 0.3 micrograms.kg-1.min-1 at 0.7 and 1.1 MAC). Similar mean arterial blood pressures and heart rates resulted from like infusions of epinephrine during I653 and isoflurane anesthesia. PVCs occurred at lesser infusion rates of epinephrine and at lower mean arterial blood pressures and heart rates with halothane than with I653 or isoflurane. Anesthetic concentration, over the range studied, did not alter the infusion rate of epinephrine required to produce arrhythmias with any anesthetic. The authors conclude that I-653 and isoflurane have similar properties with respect to epinephrine-induced arrhythmias and increases in heart rate and arterial blood pressure.