Background Cumulative ventricular pacing (VP) is associated with development of atrial fibrillation and cardiac remodelling. Contemporary pacemaker devices are able to quantify atrial high-rate episodes (AHREs) and atrial fibrillation burden (AFB). No previous study has investigated the relationship of reverse LA remodelling and AHRE. We tested the hypothesis that reverse LA remodelling parameters are associated with greater AF burden and larger percentage of cumulative ventricular pacing in pacemaker population.

Methods 101 patients [mean age 72±11 years, 69 (68%) men), mean follow-up of 359.09±83.85 days] with dual-chamber pacemaker underwent two-dimension (2D) and tissue Doppler imaging (TDI) echocardiography. LA volume (LAV) was evaluated by area-length method and function by septal A'. LV systolic and diastolic parameters were evaluated by mitral inflow velocity (E, A), LV ejection fraction (biplane Simpson's) and septal TDI velocity. The presence of AHREs (defined by atrial-rate ≥220 bpm and ≥5 min) and AFB were derived from pacemaker diagnostics.

Results The incidence of AHRE in our study was 35% (n=35) with median percentage AF burden of 2.6 (IQR 0.1–26.4). Patients with AHREs had significantly larger LA volume (p=0.014) and reduced LA function at follow-up (p=0.034), as were LV diastolic parameters, LV and RV longitudinal systolic function (all p<0.05) [Abstract 058 table 1]. AFB correlated well with LAV (R=0.505, p=0.003), E/A (R=0.545, p=0.002) and inversely correlated with Septal A' (R=0.548, p=0.001). Stepwise regression analysis demonstrated that percentage atrial pacing (OR 2.28, p=0.032) and E/A ratio (OR 4.14, p<0.01) were independently predictive of greater AF burden. On linear regression analysis, E/A, Sep A', AF burden remained predictive of changes in LA volume (all p<0.05).

Conclusion Reverse LA remodelling (increased LA volume and decreased global LA function) is evident in patients with AHREs despite similar cumulative atrial and ventricular pacing. This increased AF burden was associated with reverse LA remodelling, as was cumulative AP and diastolic parameters. These structural and functional changes within the LA may predispose individuals to develop AHREs and increased AF burden.