Effects of flecainide on defibrillation thresholds in the anesthetized dog

• Published in: Journal of the American College of Cardiology Vol. 14; no. 3; pp. 777 - 781
• Main Authors: Hernandez, Rosa, Mann, David E., Breckinridge, Susan, Williams, Gerald R., Reiter, Michael J.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.09.1989; Elsevier Science
• Subjects: Animals; Antiarythmic agents; Biological and medical sciences; Cardiac Pacing, Artificial; Cardiovascular system; Dogs; Electric Countershock; Electrocardiography; Female; Flecainide - pharmacology; Male; Medical sciences; Pharmacology. Drug treatments; Ventricular Fibrillation - physiopathology; Ventricular Fibrillation - therapy; Heart; Fissipedia; Carnivora; Arrhythmia; Cardiovascular disease; Excitability disorder; Ventricular fibrillation; Vertebrata; Chemotherapy; Mammalia; Treatment; Animal; Defibrillation; Dog; Antiarrhythmia agent; Threshold
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/0735-1097(89)90125-3

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.