Intravenous dofetilide, a class III antiarrhythmic agent, for the termination of sustained atrial fibrillation or flutter. Intravenous Dofetilide Investigators.
OBJECTIVE
This study sought to determine the safety and efficacy of a single bolus of intravenous dofetilide, a pure class III antiarrhythmic agent, for the termination of sustained atrial fibrillation or flutter.


BACKGROUND
Dofetilide is a highly selective blocker of the rapid component of the delayed rectifier current causing action potential prolongation. These effects, and preliminary clinical data, suggest that it may be effective in the treatment of atrial fibrillation and flutter.


METHODS
Ninety-one patients with sustained atrial fibrillation (75 patients) or flutter (16 patients) were entered into a double-blind, randomized multicenter study of one of two doses of dofetilide (4 or 8 micrograms/kg body weight) or placebo.


RESULTS
Dofetilide effectively terminated the arrhythmia in 31% of patients receiving 8 micrograms/kg, a statistically significant difference from those receiving 4 micrograms/kg (conversion rate 12.5%, p < 0.05) or placebo (no conversion, p < 0.01). Patients with atrial flutter had a greater response to dofetilide (54% conversion rate) than those with atrial fibrillation (14.5% conversion rate, p < 0.001).


CONCLUSIONS
Intravenous dofetilide can convert sustained atrial fibrillation or flutter to sinus rhythm. However, its efficacy is greater in flutter--a response that contrasts with the poorer response seen with class I agents. This finding potentially represents an important advance in the pharmacologic termination of atrial flutter.
Falk
R H
RH
Division of Cardiology, Boston Medical Center, Massachusetts 02118, USA. rfalk@bu.edu
Pollak
A
A
Singh
S N
SN
Friedrich
T
T
D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D001282:Atrial Flutter / Q000188:drug therapy*; D004311:Double-Blind Method; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D010627:Phenethylamines / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D013449:Sulfonamides / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D010627:Phenethylamines; D013449:Sulfonamides; C063533:dofetilide