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

Background: Although suppression of premature ventricular contractions (PVCs) is not a predictor of mortality over the long term, the extent of PVC suppression 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, double‐blind, and placebo controlled. Subjects received a single‐blind, IV infusion 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 infusion of 4 g/kg followed by a 60‐min maintenance infusion of 3.5 g/kg, for a total dose of 7.5 g/kg). Results: Dofetilide produced an 82.6% and placebo a 2.9% median reduction in PVCs. Drug responder rate, defined as 80% reduction in PVCs, was 50% in the dofetilide group and 0% in the placebo group. Conclusion: Intravenous dofetilide significantly reduced PVCs in patients who had > 30 PVCs/h at baseline, and it produced ≥ 80% reduction in PVCs in 50% of all subjects.