Safety and Acceptability of Implantation of Internal Cardioverter-Defibrillators Under Local Anesthetic and Conscious Sedation


Address for reprints: Adam P. Fitzpatrick, M.D., F.R.C.P., F.A.C.C., Manchester Heart Centre, Oxford Road, Manchester M13 9WL, UK. Fax: +44-0161-2768911; e-mail:


Background: Implantation and testing of implantable defibrillators (ICDs) using local anesthetic and conscious sedation is widely practiced; however, some centers still use general anesthesia. We assessed safety and patient acceptability for implantation of defibrillators using local anesthetic and conscious sedation.

Methods: The records of 500 consecutive device implants from two UK cardiac centers implanted under local anesthetic and conscious sedation from January 1996 to December 2004 were reviewed. Procedure time, left ventricular ejection fraction (LVEF) sedative dosage (midazolam), analgesic dosage (fentanyl or diamorphine), requirement for drug reversal, and respiratory support were recorded. Patient acceptability of the procedure was also assessed.

Results: Of 500 implants examined, 387 were ICDs, 88 were biventricular ICDs, and 25 were generator changes. Patients with biventricular-ICDs had significantly longer (mean ± SD) procedure times 129.7 ± 7.6 minutes versus 63.3 ± 32.3 minutes; P < 0.0001 and lower LVEF 24.4 ± 8.4% versus 35.7 ± 15.4%; P < 0.0001. There were no differences in the doses (mean ± SD) of midazolam 8.9 ± 3.5 mg versus 8.0 ± 3.1 mg; P = NS, diamorphine 4.3 ± 2.0 mg versus 3.8 ± 1.7 mg; P = NS or fentanyl 94.4 ± 53.7 mcg versus 92.2 ± 48.6 mcg; P = NS, between the two groups. There were no deaths or tracheal intubations in either group. Acceptability was available for 373 of 500 (75%) patients, 41 of 373 (11%) described “discomfort,” but from these 41 patients only 14 of 373 (3.8%) declined a second procedure under the same conditions.

Conclusions: Implantation of defibrillators under local anesthetic and sedation is safe and acceptable to patients. General anesthesia is no longer routinely required for implantation of defibrillators.