The overall number of premature MEK162 cost Atrial beats, the number and the total duration of AF episodes and the percentage of atrial and ventricular pacing in synchronous rhythm during the observation period were carefully noted. For each AF episode, the device stored simultaneous atrial and ventricular EGMs. Atrial tachycardia episodes, identified by regular atrial activity, were excluded from the analysis. Data from the first 2 weeks of each 3-month cross-over period

were excluded Inhibitors,research,lifescience,medical from the analysis to minimize carry-over effects. Statistical analysis Statistical analysis was performed using Student’s t-test. P values < 0.05 were considered to be statistically significant. Continuous variables are Inhibitors,research,lifescience,medical expressed as mean ± standard deviation. Analyses were performed using the statistical package SPSS 11.0 software for Windows (SPSS Inc., Chicago, IL, USA). Results From the cohort of 50 patients with DM1, first enrolled in the study, 10 were excluded due to following reasons: far-field ventricular sensing, despite Inhibitors,research,lifescience,medical refractory periods reprogramming (3 cases); atrial undersensing

(4 cases); and persistent AF during follow-up (3 cases). The remaining 40 patients (29M:11F; age 51.3 ± 7.3) underwent dual-chamber PM implantation for first-degree atrio-ventricular block (AVB) with a pathological infra- Hissian conduction (18 patients), symptomatic type 1 AVB (12 patients), and type 2 second degree AVB (10 patients). No statistically significant differences in the electrical parameters (P-wave amplitude, pacing threshold, and lead impedance) nor in the medication intake were found at implantation, between the group of patients with RAA and in the group with Inhibitors,research,lifescience,medical BB lead placement. The baseline characteristics of the study population are shown in Table 1. Table 1. Characteristics of the study population. Atrial pacing and atrial fibrillation A statistically Inhibitors,research,lifescience,medical significant difference was

found in the number of AF episodes between no treatment (APP OFF phases) group and active treatment (APP ON phases) group, during the follow-up period. In fact during active treatment a lower number Bay 11-7085 of AF episodes was registered compared with that registered during no treatment (134 ± 21 vs. 302 ± 35; p = 0.03). Furthermore, while no statistically significant difference was found in the overall duration of AF episodes between the two phases (7987 ± 963 vs. 8690 ± 612 minutes; P = 0.07), a difference statistically different was obtained in the mean duration of AF episodes, that during APP ON phases was longer than that registered during APP OFF phases (95 ± 16 vs. 32 ± 11 min; p < 0.004). On the other hand, the ventricular pacing percentage did not show statistical variation (11% vs. 9%; P = 0.2) during both phases. Atrial premature beats were significantly higher during APP OFF phases than during APP ON phases (58.651 ± 41.724 vs. 13.731 ± 9.652 beats; P = 0.005).