Aims : It has been demonstrated that atrial fibrillation (AF) frequently recurred after cardioversion (CV) using direct current (DC) or catheter ablation (CA) in patients with persistent (PeAF) or chronic AF (CAF). We hypothesized that acute results of DC CV, requirement of DC energy and additional use of antiarrhythmic drugs (AADs) for the successful CV could predict long-term clinical outcome after CA in patients with PeAF and CAF.
Methods : From 2006 to 2009, Ninty-four patients with PeAF and CAF who had undergone elective DC CV before CA were studied. The parameters associated with DC CV, including number of shocks, highest energy adjusted, with or without intravenous amiodarone use, and other clinical parameters were assessed. The time interval between CV and CA was 3.4짹2.4months.
Results : Thirty two out of the 94 patients (34%) experienced AF recurrence during the follow-up of 15.3짹12.6months. The average time to recurrence of AF after CA was 9.2짹3.2 months. Of the 62 patients, 29 patients (46.8%) remained sinus rhythm (SR) without AAD. Compared with patients with AF recurrence, body mass index (BMI) was smaller (p=0.005), total duration of AF was shorter (p=0.003), and the prevalence of diabetes was lower (p=0.003) in those who maintained SR. Total number of shocks, total energy and highest shock energy during CV were lower (p=0.001, p=0.026, p=0.006 respectively) in patients with SR during the follow-up. The patients who required amiodarone IV for successful CV had better outcome than those who did not (p=0.05) but multivariate analysis did not confirm statistical difference between two groups (p=0.06).
Conclusion : The DC energy parameters and additional use of IV amiodarone required for successful CV were clinically useful to predict the long-term outcome after CA in patients with PeAF and CAF. Further study is warranted to determine whether these DC energy parameters are related to the chronicity or electroanatomical remodeling of AF.