Abstract
The effects of three anesthetic agents on the inducibility of ventricular tachycardia by programmed stimulation were investigated in dogs with a surgically induced left ventricular infarct. Endocardial catheter electrodes were placed at the right ventricular apex under general anesthesia at least 2 weeks after infarction, and the dogs were allowed to recover for 24 hours before undergoing programmed stimulation in the conscious state on two occasions 2 hours apart. A protocol of programmed stimulation with up to seven ventricular extrastimuli was used. In 15 animals, ventricular tachycardia was inducible on both occasions with 3.4 +/- 0.4 (mean +/- SEM; range, 1-5) extrastimuli. Two hours after baseline conscious induction, the dogs were anesthetized with either halothane, pentobarbital, or a fixed combination of fentanyl-droperidol plus nitrous oxide. Halothane prolonged the PR interval from 99 +/- 4 to 117 +/- 6 msec (p = 0.001) and the ventricular effective refractory period from 140 +/- 4 to 157 +/- 6...