Aims: 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 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 dual-chamber pacemakers (DDDRs).
Methods and results: We analysed data from 396 patients who received DDDR pacemakers in the DANPACE trial. The percentage of atrial pacing (%AP) was compared with the number of mode-switch (MS) episodes collected by the pacemaker at each follow-up as an indicator of AF. Mean follow-up was 4.2 ± 2.4 years. The mean proportion of atrial and ventricular pacing was 59 ± 31 and 65 ± 33%, respectively. Approximately 72% developed AF as indicated by MS episodes at some point during follow-up. Unadjusted regression analysis indicated a relation between %AP and AF (P = 0.04), but after adjustment for possible confounders (sex, age, hypertension, diabetes, myocardial infarction, PQ interval, and left atrial diameter) there was no significant relationship (P = 0.37).
Conclusion: Atrial fibrillation is very common among patients with SSS. No association between %AP and development of AF was found in patients with SSS. Future trials may randomize patients to different levels of AP exposure.
Keywords: Atrial fibrillation; Pacemakers; Pacing; Sick sinus syndrome; Sinoatrial node.