Different effects of epoprostenol on ischemia-induced ventricular arrhythmias in dogs

In 60 randomized dogs the effects of epoprostenol infusion (100 ng/kg/min) on ischemia-induced premature ventricular contractions (PVCs), ventricular tachycardia (VT), ventricular flutters and ventricular fibrillation were studied. The circumflex coronary artery occlusion canine model of sudden death was used. The results demonstrate different effects of epoprostenol on ischemia-induced ventricular arrhythmias: 1) both postischemic (7 of 30 vs 15 of 30, p = 0.0298) and postreperfusion (5 of 23 vs 8 of 15, p = 0.0492) ventricular fibrillations were prevented in epoprostenol dogs with an improvement of the global survival rate (18 of 30 vs 7 of 30, p = 0.0019) as compared to controls; 2) in epoprostenol treated dogs a significantly increased incidence of non lethal arrhythmias-including ventricular flutters that occurred in 12 of 30 dogs vs 4 of 30 in controls (p = 0.0195)--was observed; 3) a positive correlation between the percent diastolic pressure fall 10 min after the start of epoprostenol infusion and the number of non lethal arrhythmias was noted. However, hemodynamic effects of the compound, suggesting an oxygen sparing action, did not preclude the antifibrillatory effectiveness. Thus, the antifibrillatory and antiarrhythmic effects of epoprostenol after circumflex coronary artery occlusion and reperfusion in dogs seem independent from one another.