Abstract 116 Poster Session II, Sunday, 5/2 (poster 243)

Introduction: Radiofrequency catheter ablation (RFCA) of tachydysrhythmias (i.e. WPW Syndrome) typically requires general anesthesia in children. Several studies have demonstrated that alfentanilmidazolam1, propofol, isoflurane2, halothane and sevoflurane3 do not significantly alter the electrophysiology of the normal or aberrant conduction systems. Others reported difficulty in establishing SVT during general anesthesia.4 The purpose of this report is to compare the effects of administering general anesthesia with either isoflurane or low dose propofol infusions on establishing SVT in children undergoing RFCA.

Methods: A review of 38 patients having RFCA for SVT was conducted. Anesthetic records were examined for patient age, weight, and diagnosis. Anesthetic technique and case length were also noted. Catheterization reports and electrophysiology recording were reviewed for baseline assessment, the onset of SVT and the need for isoproterenol for initiation of SVT. Student t-test and Fisher's exact test were used to analyze the data.

Results: Maintenance of anesthesia was established in 17 patients with isoflurane while 21 patients received propofol infusions. Isoflurane concentrations varied through the cases from 0.25 to 1%. Propofol infusions were between 50-100 mcg/kg/min. Concurrent use of fentanyl for analgesia and midazolam for amnesia occurred in both groups. Vecuronium was the muscle relaxant of choice. The results are as follows: (Table)

Table 1 No caption available
Full size table

Discussion: The results support the contention that general anesthesia with inhalation agents may interfere with the induction of SVT during general anesthesia. The length of time to the initiation of SVT and the need for isoproterenol were both significantly greater in patients receiving isoflurane as compared to patients receiving propofol infusions. Numerous variable, including depth of anesthesia and operator experience, must be considered for a complete analysis of these two different anesthetic techniques. A randomized, double blinded study is required to test these variables.