Early recurrences of atrial fibrillation after electrical cardioversion: a result of fibrillation-induced electrical remodeling of the atria?
OBJECTIVE
We sought to investigate whether, in humans, the timing and incidence of a relapse of atrial fibrillation (AF) during the first month after cardioversion indicates the presence of electrical remodeling and whether this could be influenced by prevention of intracellular calcium overload during AF.


BACKGROUND
Animal experiments have shown that AF induces shortening of the atrial refractory period, resulting in an increased vulnerability for reinduction of AF. This electrical remodeling was completely reversible within 1 week after cardioversion of AF and was presumably related to intracellular calcium overload.


METHODS
Using transtelephonic monitoring in 61 patients cardioverted for chronic AF, we evaluated the daily incidence of recurrence of AF and determined, by Cox regression analysis, the influence of patient characteristics and medication on relapse of AF.


RESULTS
During 1 month of follow-up, 35 patients (57%) had a relapse of AF, with a peak incidence during the first 5 days after cardioversion. Furthermore, in patients with a recurrence of AF, there was a positive correlation between the duration of the shortest coupling interval of the premature atrial beats after cardioversion and the timing of the recurrence of AF (p = 0.0013). Multivariate analysis revealed that the use of intracellular calcium-lowering drugs during AF was the only significant variable related to maintenance of sinus rhythm after cardioversion (p = 0.03).


CONCLUSIONS
The daily distribution of recurrences of AF suggests a temporary vulnerable electrophysiologic state of the atria. Use of intracellular calcium-lowering medications during AF appeared to reduce recurrences, possibly due to a reduction of electrical remodeling during AF.
Tieleman
R G
RG
Department of Cardiology, Thoraxcenter, University Hospital, Groningen, The Netherlands.
Van Gelder
I C
IC
Crijns
H J
HJ
De Kam
P J
PJ
Van Den Berg
M P
MP
Haaksma
J
J
Van Der Woude
H J
HJ
Allessie
M A
MA
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy*; D002908:Chronic Disease; D004554:Electric Countershock; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D016019:Survival Analysis; D013997:Time Factors; D017211:Treatment Failure
D000889:Anti-Arrhythmia Agents