Background
Dofetilide, an IKr blocker has been demonstrated to be effective in terminating persistent atrial fibrillation and flutter (AF/AFL), and in
maintaining sinus rhythm after direct current cardioversion (CV). It is not known, however, whether pharmacological conversion
with dofetilide predicts maintenance of sinus rhythm. In addition, there is limited information comparing the efficacy of
dofetilide in persistent versus paroxysmal AF/AFL.
Methods and Results
Eighty consecutive patients with AF/AFL (51 persistent, 29 paroxysmal) admitted for initiation of dofetilide were studied.
Termination of persistent AF/AFL occurred in 61% of patients while 39% required CV. After 21 ± 19 months of follow-up, 37%
of patients with persistent AF/AFL were free of recurrence. Acute conversion with dofetilide did not predict long term efficacy.
Dofetilide was more effective in maintaining sinus rhythm in patients with AFL (65%) than in those with AF (25%) (p < 0.05). Dofetilide was more likely to maintain sinus rhythm in patients with persistent than paroxysmal AF/AFL (37 vs. 14%;
p < 0.05). Torsades de Pointes developed in two patients despite careful dosing and monitoring of QT changes.
Conclusions
Dofetilide is more effective in patients with persistent than in those with paroxysmal AF/AFL. Importantly, short-term response
does not necessarily predict long-term efficacy. Significant proarrhythmia can occur even with careful in-hospital monitoring.
Keywords Atrial fibrillation - Dofetilide - Antiarrhythmic drugs
Dr. Banchs and Dr. Wolbrette contributed equally to this study.
Presented in abstract form at the XIII World Congress on Cardiac Pacing and Electrophysiology; December 3, 2007; Rome and
published in abstract form (Giornale Italiano di Aritmologia e Cardiostimolazione 2007;10(3):26).