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Abstract

# 1365 Does atrial pacing lead to atrial fibrillation in patients with sick sinus syndrome? Insights from the DANPACE trial {#article-title-2} Purpose: Paroxysmal atrial fibrillation (AF) is common in patients with sick-sinus syndrome (SSS) and pacemakers leading to morbidity and an increased risk of stroke or death. Previous studies indicate that atrial pacing may precipitate atrial fibrillation (AF). We investigated the relation between atrial pacing and the occurrence of AF during long-term follow-up among patients with SSS, no prior AF, and DDDR pacemakers. Methods: We analysed data from 396 patients who received DDDR pacemakers in the DANPACE trial. The rate adaptive function was activated and programmed with a lower rate of 60 beats per minute and an upper rate of 130 beats per minute. The paced atrio-ventricular interval (AVI) was programmed to 140-220 ms according to a pre-specified algorithm. Follow-up took place after 3 months and again every year after implantation up to 10 years. The percentage of atrial pacing (%AP) was compared to the number of mode switch (MS) episodes collected by the pacemaker at each follow-up as an indicator of AF. Results: Mean follow-up was 4.2 ± 2.4 years. The mean proportion of atrial and ventricular pacing was 59±31 % and 65±33 %, respectively. A total of 333 patients (84 %) developed AF as indicated by MS episodes at some point during follow-up (figure). Unadjusted regression analysis indicated a relation between %AP and AF (P = 0.04), but after adjustment for possible confounders (sex, age, hypertension, diabetes, MI, PQ interval, and left atrial diameter) there was no significant relationship (P = 0.37). Conclusion: Atrial fibrillation is highly frequent among patients with SSS. No association between %AP and development of AF was found in patients with SSS. Future trials may randomise patients to different levels of AP exposure. ![Graphic][1] [1]: /embed/inline-graphic-1.gif