Atrial fibrillation in patients with sick sinus syndrome: the association with PQ-interval and percentage of ventricular pacing.

AIMS In the recently published DANPACE trial, incidence of atrial fibrillation (AF) was significantly higher with single-lead atrial (AAIR) pacing than with dual-chamber (DDDR) pacing. The present analysis aimed to evaluate the importance of baseline PQ-interval and percentage of ventricular pacing (VP) on AF. METHODS AND RESULTS We analysed data on AF during follow-up in 1415 patients included in the DANPACE trial. In a subgroup of 650 patients with DDDR pacemaker, we studied whether %VP, baseline PQ-interval, and programmed atrio-ventricular interval (AVI) was associated with AF burden measured as time in mode-switch (MS) detected by the pacemaker. In the entire DANPACE study population, the incidence of AF was significantly higher in patients with baseline PQ-interval >180 ms (P< 0.001). Among 650 patients with DDDR pacemaker, telemetry data were available for 1.337 ± 786 days, %VP was 66 ± 33%, AF was detected at planned follow-up in 160 patients (24.6%), MS occurred in 422 patients (64.9%), and AF burden was marginally higher with baseline PQ-interval >180 ms (P= 0.028). No significant association was detected between %VP and %MS (Spearman's ρ 0.056, P= 0.154). %MS was not different between minimal-paced programmed AVI ≤ 100 and >100 ms (median value), respectively (P= 0.60). CONCLUSIONS The present study indicates that a longer baseline PQ-interval is associated with an increased risk of AF in patients with sick sinus syndrome. Atrial fibrillation burden is not associated with the percentage of VP or the length of the programmed AVI.