Pacemaker-Treated Patients with Sick Sinus Syndrome: Atrial Fibrillation Burden

Atrial fibrillation (AF) is common in patients with sick-sinus syndrome (SSS). Previous studies showed that atrial pacing may reduce AF burden. But in fact, pacemaker-treated patients with SSS have a high percentage of AF that tends to increase according to long-term follow-up.

Purpose: Influence of atrial pacing and echocardiography data on the incidence and duration of AF in patients with SSS after pacemaker implantation (DDDR).

Methods: We investigated the relation between atrial pacing at the right atrial appendage, echocardiography data and the occurrence of AF during long-term follow-up, FU (18 months) among 55 patients with SSS, tachy-brady form, and DDDR pacemakers without active specific atrial pacing algorithms. The percentage of atrial pacing (AP) was compared with the number of mode-switch (MS) episodes collected by the pacemaker at each FU as an AF indicator, and with echocardiography data at baseline and 18 month FU. Patients were reviewed every 6 months and all pacemaker data were downloaded.

Results: The mean percentage of AP was 65±24% after 6 month FU and 72±12% at 18 month FU with uncertain increase in the proportion of stimulation, P=0.32. The mean proportion of ventricular pacing was 24±15% at first FU and 28±17% at 18 month FU without statistical differences between any 6 months. 39 patients (76%) developed 6 month increment of AF, 6.7% as indicated by MS episodes. There was relationship between increasing left atrial diameter and the number of MS episodes, r=0.51. The patients (N=26) with left atrial diameter ≥44.4mm demonstrated occurrence of persistent AF. Patients with the development of persistent AF had no differences in the percentage of ventricular pacing compared with patients without persistent AF, P=0.15.

Conclusions: In patients with paroxysmal AF and SSS requiring pacemaker implantation, an atrial pacing did not prevent the development of persistent AF. No association between percentage of AP and AF development was found. Increasing left atrial diameter is an independent marker of AF burden.