Does flecainide regain its antiarrhythmic activity after electrical cardioversion of persistent atrial fibrillation?
OBJECTIVE
The purpose of this study was to evaluate the hypothesis that presumed reversion of electrical remodeling after cardioversion of atrial fibrillation (AF) restores the efficacy of flecainide.


BACKGROUND
Flecainide loses its efficacy to cardiovert when AF has been present for more than 24 hours. Most probably, the loss is caused by atrial electrical remodeling. Studies suggest electrical remodeling is completely reversible within 4 days after restoration of sinus rhythm (SR).


METHODS
One hundred eighty-one patients with persistent AF (median duration 3 months) were included in this prospective study. After failure of pharmacologic cardioversion by flecainide 2 mg/kg IV (maximum 150 mg in 10 minutes) and subsequent successful electrical cardioversion, we performed intense transtelephonic rhythm monitoring three times daily for 1 month. In case of AF recurrence, a second cardioversion by flecainide was attempted as soon as possible.


RESULTS
AF recurred in 123 patients (68%). Successful cardioversion by flecainide occurred only when SR had been maintained for more than 4 days (7/51 patients [14%]). Failure to cardiovert was associated with a prolonged duration of the recurrent AF episode and concurrent digoxin use. Multivariate logistic regression confirmed that successful cardioversion was determined by digoxin use (odds ratio [OR] 0.093, P = .047) and by the interaction between the duration of SR and the (inverse) duration of recurrent AF (OR 6.499, P < .001). When flecainide was administered within 10 hours after AF onset and the duration of SR was greater than 4 days, the success rate was 58%.


CONCLUSIONS
Flecainide recovers its antiarrhythmic action after cardioversion of AF. However, successful pharmacologic cardioversion occurs only after SR has lasted at least 4 days and is expected only for recurrences having duration of a few hours. Immediate pharmacologic cardioversion of AF recurrence may be a worthwhile strategy for management of persistent AF.
Tieleman
Robert G
RG
University Hospital Maastricht, The Netherlands. r.tieleman@fys.unimaas.nl
Van Gelder
Isabelle C
IC
Bosker
Hans A
HA
Kingma
Tsjerk
T
Wilde
Arthur A M
AA
Kirchhof
Charles J H J
CJ
Bennekers
Johan H
JH
Bracke
Frank A L E
FA
Veeger
Nic J G M
NJ
Haaksma
Jaap
J
Allessie
Maurits A
MA
Crijns
Harry J G M
HJ
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology / Q000628:therapy; D004554:Electric Countershock; D005260:Female; D005424:Flecainide / Q000494:pharmacology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012008:Recurrence; D013997:Time Factors
D000889:Anti-Arrhythmia Agents; D005424:Flecainide