Author + information
- Received August 2, 1988
- Revision received December 7, 1988
- Accepted February 13, 1989
- Published online September 1, 1989.
- Rosa Hernandez, MD1,
- David E. Mann, MD, FACC1,
- Susan Breckinridge, RN1,
- Gerald R. Williams, BS1 and
- Michael J. Reiter, MD, PHD, FACC∗,1
- ↵∗Address for reprints: Michael J. Reiter, MD, Director, Cardiac Electrophysiology Laboratory, Division of Cardiology, Box B130, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, Colorado 80262.
The effects of fiecainide on defibrillation thresholds in 21 open chest, anesthetized dogs were studied. Defibrillation was accomplished using nontruncated exponential pulses delivered through two epicardial patches. Multiple shocks of varying energy were administered after 10 s of ventricular fibrillation in random order. The percent success was plotted against the energy delivered for each dog. A sigmoidal curve was fit to the data and the energy associated with 50% success (E50) calculated. Flecainide (n = 16) or saline solution (n = 5) was then infused and E50again determined. Flecainide infusion produced mean (standard error of the mean) plasma levels of 610111 ng/ml.
Defibrillation thresholds were obtainable in 10 of 16 dogs that received fiecainide infusion. Flecainide infusion increased E50by 75% (from 6.5 ± 1.9 to 11.4 ± 2.6 J) (p < 0.05). Infusion of saline solution did not significantly affect defibrillation energy. Of 16 dogs that received flecainide infusion, 12 had one or more complications: 6 had ventricular fibrillation resistant to defibrillation, 6 developed severe hypotension after successful defibrillation and 5 had spontaneous ventricular fibrillation after successful defibrillation. These effects were not seen in any control dogs.
Flecainide infusion significantly increases defibrillation threshold and has important adverse arrhythmic and hemodynamic effects in this experimental preparation.
↵1 We are indebted to Holly Coller for capable technical help, Pamela Bland for secretarial assistance and Drs. JoAnn Lindenfeld and Lawrence Horwitz for helpful review of the manuscript. We thank Wayne Leanza for providing the custom-built defibrillator, and Bruce Raykowski of CPI for providing the defibrillator patches.
☆ This work was supported in part by contributions from a concerned group of Colorado businessmen.
- Received August 2, 1988.
- Revision received December 7, 1988.
- Accepted February 13, 1989.