Effect of local lidocaine anesthesia on ventricular escape intervals during permanent pacemaker implantation in patients with complete heart block

Transient asystole is often noted during the course of permanent pacemaker implantation in patients with complete heart block. Since subcutaneous lidocaine is frequently used as the local anesthetic agent for permanent pacemaker implantation, the effect of this drug on ventricular escape intervals was studied. Ventricular escape intervals after transient cessation of pacing were studied in 9 patients with complete heart block before and 10, 30, and 45 minutes after subcutaneous lidocaine administration for permanent pacemaker implantation. The total lidocaine dose ranged from 170 to 400 mg (1.9 to 9.5 mg/kg of body weight). Therapeutic blood levels were achieved in 7 patients. The mean ventricular escape interval before lidocaine was 1.83 +/- 0.32 seconds, which increased to 2.58 +/- 1.35, 2.96 +/- 1.06, and 2.68 +/- 1.27 seconds at 10, 30, and 45 minutes after lidocaine (p less than 0.02). The mean maximal escape interval before lidocaine was 2.06 +/- 0.30 seconds, which increased to 3.80 +/- 1.44 seconds (p less than 0.01), a mean increase of 84%. The percent increase in maximal escape interval was related directly to the peak lidocaine level achieved. After lidocaine administration, 5 patients had asystole greater than 4 seconds and 1 required resumption of pacing. Thus, subcutaneous lidocaine contributes to the occurrence of asystole seen during permanent pacemaker implantation. It is advisable to limit the amount of lidocaine administered during permanent pacemaker implantation to the minimum necessary to achieve adequate local anesthesia. Strong consideration should be given to the use of a temporary pacemaker in patients with complete heart block during permanent pacemaker implantation even in the absence of previous asystole.