Effect of General Anesthesia on the Defibrillation Energy Requirement in Patients Undergoing Defibrillator Implantation

Background: The effect of general anesthesia on defibrillation efficacy in humans is not known. The purpose of this study was to determine the effect of general anesthesia on the defibrillation energy requirements in patients undergoing implantation of a pectoral defibrillator. Methods and Results: Nineteen consecutive patients who underwent defibrillator implantation under general anesthesia were prospectively compared to 16 consecutive patients who underwent defibrillator implantation by the same physicians, using similar devices, at another hospital under conscious sedation. Pre-discharge testing was performed 1.4 ± 1.0 days after implant using sedation in both groups. The defibrillation energy requirement was determined using the same predefined step-down protocol (15, 10, 8, 5, 3, 1 J) at the time of implantation and during pre-discharge testing. The clinical characteristics of the patients were similar between groups. There was no significant difference in the mean implant defibrillation energy requirement compared to the mean pre-discharge defibrillation energy requirement in either the general anesthesia group (8.5 ± 4.7 vs. 8.4 ± 3.4 J; p = 0.9) or in the conscious sedation group (9.4 ± 3.9 vs. 9.0 ± 3.8 J; p = 0.7). Conclusions: When compared to conscious sedation, general anesthesia with mechanical ventilation has no significant effect on defibrillation efficacy in patients undergoing defibrillator implantation.