EFFICACY AND SAFETY OF DOFETILIDE, A NEW CLASS-III ANTIARRHYTHMIC AGENT, IN ACUTE TERMINATION OF ATRIAL-FIBRILLATION OR FLUTTER AFTER CORONARY-ARTERY BYPASS-SURGERY

Ninety-eight patients, who developed atrial fibrillation/flutter after coronary artery bypass grafting within 1-6 days after surgery, were i ncluded into a double-blind, placebo-controlled, randomized trial to a ssess the efficacy and safety of dofetilide. Patients were randomly al located to dofetilide 4 mu g/kg i.v. (n=33), dofetilide 8 mu g/kg i.v. (n=32) or placebo (n=33) given intravenously over 15 min at a constan t infusion rate. Responders were defined as patients who converted to sinus rhythm at any time during the initial 3 h after the start of the infusion. The conversion rates were 24% (8/33) on placebo, 36% (12/33 ) on dofetilide 4 mu g/kg, and 44% (14/32) on dofetilide 8 mu g/kg. Th e P-values (two-tailed) were 0.27 for dofetilide 4 mu g/kg vs. placebo , O.11 for dofetilide 8 mu g/kg vs. placebo, and 0.10 for dose-respons e relationship. Short episodes of aberrant ventricular conduction and ventricular tachycardia were seen separately in three subjects after d ofetilide 8 mu g/kg. No episodes of torsades de pointes were noted. No negative inotropic effect was noted. In conclusion, dofetilide was we ll tolerated, bur the effects on atrial fibrillation/flutter did not a ttain statistical significance, possibly due to the high placebo conve rsion rate. Copyright (C) 1997 Elsevier Science Ireland Ltd.