Safety of rapid switching from amiodarone to dofetilide in atrial fibrillation patients with an implantable cardioverter-defibrillator.

BACKGROUND

Dofetilide is a class III antiarrhythmic drug commonly used for treatment of atrial fibrillation. Drug guidelines mandate a 3-month waiting period before initiating dofetilide after amiodarone use. Whether patients with an implantable cardioverter-defibrillator (ICD) can be rapidly switched from amiodarone to dofetilide is not known.

OBJECTIVE

The purpose of this study was to evaluate whether rapid switching from amiodarone to dofetilide is safe in atrial fibrillation patients with an ICD.

METHODS

In this retrospective observational study, we assessed the feasibility and the short- and long-term safety of rapid switching from amiodarone to dofetilide in hospitalized atrial fibrillation with an ICD.

RESULTS

The study included a total of 179 patients who were followed for 12.6 ± 2.2 months. All patients had drug initiation during hospitalization. Dofetilide resulted in successful cardioversion in 66% (118/179). Twenty percent of patients (36/179) required dofetilide dose adjustments in the initiation phase because of QT prolongation and decreased creatinine clearance. A total of 6.1% of patients (11/179) required drug discontinuation. The incidence of torsades de pointes was 1.1% (2/179) during initiation. One patient (0.5%) had self-terminating ventricular tachycardia at follow-up. No other significant adverse events were noted during follow-up.

CONCLUSION

Atrial fibrillation patients with an ICD can be rapidly switched to dofetilide after 7 days of discontinuation of amiodarone without significant arrhythmia-related complications. Prospective studies with large sample sizes, especially of women, should be performed to further validate these findings.