Abstract 11799: Silent Atrial Fibrillation in Pacemaker Early Post-implantation Period: An Unintentionally Provoked Situation?

Abstract

Introduction: Identification of silent atrial fibrillation (AF) is crucial to avoid thromboembolic complications. Multiple studies have shown that atrial high rate episodes (AHREs) detected in pacemakers (PM) are related to an increased risk of stroke. Our group has also reported that AHREs are independently associated to a higher incidence of silent ischemic brain lesions (IBL) on CT-scan. Hypothesis: Our purpose is to evaluate the relation between AHREs and time from PM implantation / type of lead fixation used in patients with dual-chamber PM and no history of AF. AHREs soon after PM implantation might be related with the procedure itself and the prognosis could be different. Methods: We analyzed prospectively the incidence of AHREs > 5 min compatible with silent AF (at 3 months after inclusion and during follow-up) and the presence of silent IBL, in relation to time from implantation (≤ 3 months vs. >3 months) and the atrial lead fixation (active vs. passive). Results: We evaluated 110 consecutive patients (55% men, aged 74 ± 9 year-old) during a mean follow-up of 24 ± 8 months. Mean CHADS 2 and CHA 2 DS 2 VASc scores were 1.9 ± 1.2 and 3.5 ± 1.5, respectively. Time from PM implantation was ≤ 3 months in 88 patients (80%) and > 3 months in 22 (20%). The type of fixation used was active in 55 patients and passive in other 55 (50%). AHREs were present in 40 patients (36.4%), 16 patients (14.5%) at first 3 months and 36 patients (32.7%) after. CT-scan showed silent IBL in 26 patients (23.6%). Table. The presence of AHREs at 3 months was more frequent in the patients with PM implantation in the prior 3 months (17% vs. 4.5%, p=0.09) and significantly related to active fixation leads (OR 5.36, 1.43 - 20.07; p<0.05). The presence of silent IBL on CT-scan was related to the presence of AHREs during follow up (OR 3.12, 1.29 - 7.97; p<0.05) but not with AHREs at first 3 months (OR 1.58, 0.49 - 5.05; p=0.44). Conclusions: AHREs compatible with silent AF are really prevalent in patients receiving PM and have been associated to worse outcomes including a higher incidence of silent IBL on CT-scan. But our data show that when AHREs occur during the first 3 months after PM implantation, it could be related with the procedure and the use of active fixation leads, and these episodes might not be related to worse outcomes.