Author + information
- Received November 5, 1985
- Revision received February 12, 1986
- Accepted March 5, 1986
- Published online August 1, 1986.
- Paul Dorian, MD, MSc*,1,2,4,
- Eric S. Fain, ScB1,3,4,
- Jean-Marc Davy, MD1,3,4 and
- Roger A. Winkle, MD, FACC1,4
- ↵*Address for reprints: Paul Dorian, MD, Division of Cardiology, Toronto Western Hospital, Toronto, Ontario M5T 2S8 Canada.
To investigate the influence of lidocaine on the energy requirements for internal defibrillation, lidocaine (n = 8) or saline solution (n = 12) was administered by intravenous infusion to 20 pentobarbital-anesthetized dogs, and the likelihood of successful defibrillation was examined at various shock energy levels before and after treatment. After lidocaine administration to a mean steady state concentration of 5.6 ± 2.7 μ/ml, the mean energy required to achieve 50 and 90% success in defibrillation (E50and E90) increased by 61.1 ± 34.1% (mean ± SD, p < 0.005) and 47.1 ± 28.6% (p < 0.005), respectively. The steady state log lidocaine concentration correlated positively with the observed increase in E50(r = 0.887, p < 0.01) over a concentration range from 1.95 to 9.8 /ug/ml. In a related experiment, lidocaine infusion was administered to five dogs and then abruptly discontinued. At energy levels achieving a mean 90.0 ± 10.0% success in defibrillation before treatment, only 43.3 ± 23.4% success was achieved after 60 minutes of the lidocaine infusion (p < 0.01) at a mean plasma concentration of 8.4 ±2.1 μ/ml. The percent of successful defibrillations returned to baseline value (92.0 ± 18.0%, p < 0.01) after drug washout at a time when mean lidocaine concentration had declined to 1.8 ± 0.5 μ/ml.
Lidocaine causes a reversible, concentration-dependent increase in the energy requirements for successful defibrillation; recommendations to administer lidocaine to patients with ventricular fibrillation resistant to defibrillation may need to be reviewed.
- Received November 5, 1985.
- Revision received February 12, 1986.
- Accepted March 5, 1986.
- American College of Cardiology Foundation