Oral loading single dose flecainide for pharmacological cardioversion of recent-onset atrial fibrillation.

The efficacy and safety of the single oral loading dose of flecainide for cardioversion of recent-onset atrial fibrillation was examined by reviewing the trials on the subject identified through a comprehensive literature search. Most of the trials used a single dose of 300 mg for oral loading. The success rate ranged from 57 to 68% at 2-4 h and 75 to 91% at 8 h after drug administration. The conversion time ranged from 110+/-82 to 190+/-147 min, depending on the duration of observation after drug administration, which in most trials was of 8 h. Single oral loading regimen of flecainide was significantly more efficacious than placebo, and was as efficacious as the single oral loading regimen of propafenone. Both the single oral loading and the intravenous loading regimens of flecainide were equally efficacious but the intravenous regimen resulted in an earlier conversion. Adverse effects reported were mild non-cardiac side effects, reversible QRS complex widening, transient arrhythmias and left ventricular decompensation. The transient arrhythmias were chiefly at the time of conversion and included appearance of atrial flutter and sinus pauses. No life-threatening ventricular arrhythmia or death was reported. The single dose oral loading regimen of flecainide appears to be effective for cardioversion of recent-onset atrial fibrillation with a relatively rapid effect within 2-4 h, and is free of serious complications in patients without structural heart disease. Patients with substantial structural heart disease were excluded from most of the trials.