Page 79 - ADD-ON ABLATION SURGERY IN PATIENTS WITH ATRIAL FIBRILLATION

is evidence that this condition tends to resolve within the first post-operative month when the myocardial edema tends to disappear22, 44. In contrast, the genesis of late recurrence might be attributed to lesion incompleteness45 Since early recurrences are thought to be inflammatory-mediated, we could expect that ECV performed after a 3-month blanking period might be associated with a lower recurrence rate. In contrast, the time from surgery to ECV was significantly longer in patients with AF recurrence and time from surgery to ECV resulted to be a multivariate predictor of recurrence with a cut-off ≥ 88 days (p=0.005).This finding strongly supports the hypothesis that cardioversion should be performed within 90 days from surgery. We can postulate that this effect might be related to irreversible anatomical and electrophysiological changes in the atrial conduction tissue after this period, which might render the ECV ineffective.
Also, we failed to find any interaction between surgical ablation time-to-surgery and LA dimension, which demonstrates that surgical ablation is a primary predictor of AF recurrence and its effect is not secondary to increased left atrial size and time to ECV.
Remarkably, the use of amiodarone and other antiarrhythmics at the time of cardioversion did not influence AF recurrence after add-on surgery whereas in
isolated cardiac surgery, among patients showing AF recurrence at follow-up, the
number of those who were not in treatment with amiodarone was significantly
higher. From our data, it seems that the pre-treatment with oral amiodarone
before cardioversion improves the reversion rate in patients with AF recurrence
after mitral surgery without ablation referred for ECV. Consequently, the use of
amiodarone should be, in our opinion, highly recommended in these patients.
Amiodarone, by prolonging atrial refractoriness46-48may reverse the electrophysiological effect of the electrical remodelling, thus affecting the efficacy
of direct-current cardioversion.We can postulate that the effect of amiodarone
results not to be important in patients undergoing an associated ablation
procedure since the epicardial radiofrequency ablation leads itself to attenuated
shortening of atrial refractoriness49. 9 However, our data do not allow us to draw any final conclusion on the impact of
amiodarone on AF recurrence since drug therapy discontinuation was not based according to a study protocol but left to investigators’ decisions and this has the potential to introduce a selection bias into the study. In addition, when examining our results it is important to also consider that the decision to perform an additional ablation procedure was left to the surgeon’s preference and surgical
General discussion
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