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

Abstract

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. This study was undertaken to determine whether intravenous (i.v.) dofetilide has the ability to suppress PVCs in patients who have frequent occurrences. 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, i.v. 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). 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. Intravenous dofetilide significantly reduced PVCs in patients who had > 30 PVCs/h at baseline, and it produced > or = 80% reduction in PVCs in 50% of all subjects.