Intravenous propafenone reduces energy requirements for defibrillation in pigs

The effect of antiarrhythmic drugs on defibrillation threshold have become an important issue with the increasing use of the automatic implantable cardioverter defibrillator (AICD). In several reports antiarrhythmic therapy has been found to affect the energy required for defibrillation; the present study examined the effects of intravenous propafenone on defibrillation threshold in open chest, anesthetized pigs. Twenty health pigs were studied; 10 pigs free from any drugs (Group 1) and 10 pigs after a constant iv infusion of 0.04 mg/kg/min of propafenone (Group 2). Defibrillation threshold was 21 +/- 5, 20 +/- 5, 21 +/- 6, 19 +/- 4 and 19 +/- 6 J in Group 1 and 20 +/- 7, 18 +/- 9, 15 +/- 5, 14 +/- 7, 9 +/- 6 J in Group 2, respectively at 20, 40, 60, 80 min (p value respectively NS, NS, less than 0.05, less than 0.01, less than 0.001). We conclude that intravenous propafenone reduces the energy requirements for defibrillation in experimental animals.