Dofetilide is used for the maintenance of normal sinus rhythm in patients with atrial fibrillation/ atrial flutter of more than 1 week duration who have been converted to normal sinus rhythm. Because dofetilide can cause life-threatening ventricular arrhythmias, it should be reserved for patients in whom atrial fibrillation/ atrial flutter is highly symptomatic. Dofetilide also is used for the conversion of atrial fibrillation and atrial flutter to normal sinus rhythm. Dofetilide has not been shown to be effective in patients with paroxysmal atrial fibrillation.
In 2 randomized, double-blind, dose-response studies, about 30% of patients with atrial fibrillation/ atrial flutter who received 500 mcg of dofetilide twice daily were successfully converted to normal sinus rhythm compared with about 10 or 6% of those receiving 250 or 125 mcg twice daily and 1% of those who received placebo. Approximately 70% of the patients who successfully achieved normal sinus rhythm did so within 24-36 hours of beginning dofetilide therapy. After 12 months of therapy, the probabilities of remaining in normal sinus rhythm were 58-66 or 25-21% in patients who had converted to normal sinus rhythm and were still receiving dofetilide (500 mcg twice daily) or placebo, respectively. In one of these studies, dofetilide also was more effective than sotalol (80 mg orally twice daily) in converting atrial fibrillation to normal sinus rhythm or maintaining normal sinus rhythm for up to 12 months. In a third study, dofetilide was effective in converting and preventing the recurrence of atrial fibrillation without affecting mortality in patients with congestive heart failure and reduced left ventricular function.