Effects of intravenous dofetilide in patients with frequent premature ventricular contractions: A clinical trial

Background: Although suppression of premature ventricular contractions (PVC s) is not a predictor of mortality over the long term, the extent of PVC su ppression is an important characteristic of any antiarrhythmic drug. Hypothesis: This study was undertaken to determine whether intravenous (IV) dofetilide has the ability to suppress PVCs in patients who have frequent occurrences. Methods: Subjects were men and women, aged 18 to 75 years, with >30 PVCs/h on two consecutive 24-h Holter recordings ;while drug free, and >50 PVCs/h during a 2-hour telemetric electrocardiogram. The study was randomized, dou ble-blind, and placebo controlled. Subjects received a single-blind, IV inf usion of placebo and were randomized (3:1) to receive a double-blind second infusion of placebo or an infusion of dofetilide (a 15-min loading infusio n of 4 g/kg followed by a 60-min maintenance infusion of 3.5 g/kg, for a to tal dose of 7.5 g/kg). Results: Dofetilide produced an 82.6% and placebo a 2.9% median reduction i n PVCs. Drug responder rate, defined as 80% reduction in PVCs, was 50% in t he dofetilide group and 0% in the placebo group. Conclusion: Intravenous dofetilide significantly reduced PVCs in patients w ho had > 30 PVCs/h at baseline, and it produced greater than or equal to 80 % reduction in PVCs in 50% of all subjects.