Ambulatory Anesthetic Management of Non-Invasive Cardiac Electrophysiologic
Procedures
Sunil K. Sinha, MD, Britten Cole, MD, George Silvay, MD, PhD, Davendra Mehta, MD, PhD
Mount Sinai School of Medicine, New York, New York

BACKGROUND: Procedures involving anesthesia in patients with implantable cardioverter-defibrillator (ICD) devices are rapidly increasing as the indications for this therapy continue to expand. However, there is little published data on the safety and efficacy of anesthesia in this population undergoing ambulatory non-invasive programmed stimulation (NIPS) or ICD generator change (ICDGC).
OBJECTIVE: We sought to determine the anesthesia requirements & outcomes in ambulatory cases requiring sedation for defibrillator threshold testing (DFT) or programmed electrical stimulation (PES). DFT involves the prompt induction of VF and its treatment with ICD shocks. PES involves multiple pacing algorhythms for both VT induction & termination as well as VF induction with ICD shocks.
METHODS: Review of all ICD outpatients who underwent elective NIPS or ICDGC in the cardiac electrophysiology laboratory between January 1, 2002 and December 31, 2004. In ICDGC patients injectable 0.5% lidocaine HCl (Abbott Laboratories, North Chicago, Illinois) was used for local anesthesia. Standard monitoring (EKG, blood pressure, oxygen saturation, and end-expiratory CO2 monitoring) was recorded. Following pre-anesthetic evaluation, intravenous 1% propofol (AstraZeneca S.p.A, Caponago, Italy) was administered and titrated to desired level of anesthesia for DFT or PES. Information was
compiled and analyzed using SPSS 11.5. Statistical calculations included means & standard deviations, comparison of means using the Student’s t test and one-way analysis of variance (ANOVA). A p value < 0.05 was considered significant.
RESULTS: 73 outpatients were selected for NIPS or ICDGC in the period examined. 13 were excluded from analysis due to incomplete medical records (8) or because an ICD shock was not delivered during testing (5). The demographic and clinical characteristics of the 60 patients (29 NIPS, 31 ICDGC) included in analysis are summarized below.

Patients undergoing NIPS (86.2% PES) received an average of 118.4 ± 53.3 mg propofol for a mean 1.35 ± 0.9 shocks which was significantly more than those undergoing ICDGC (29% PES) who received an average of 62.6 ± 27.4 mg propofol for a mean 1.32 ± 0.7 shocks (p < 0.001). One-way ANOVA was applied examining additional characteristics including age, LVEF, New York Heart Association class, creatinine, shock impedance, number of shocks, and DFTs. Only age (p = 0.006) and LVEF (p = 0.039) proved significant with advancing age and lower LVEF correlating with smaller amounts of propofol anesthesia. There were no anesthetic complications (emergent intubation, hemodynamic collapse) and no ambulatory patient required unscheduled hospital admission post-procedure.
CONCLUSION: With appropriate patient selection, ambulatory anesthesia for NIPS and ICDGC is both practical and safe. Knowledge of key procedural details (in particular, whether DFT or PES shall be performed) and patient characteristics (age, LVEF) are useful predictors for the likely amount and duration of propofol anesthesia required.

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