Left atrial remodeling and reduced atrial pump function after chronic right ventricular apical pacing in patients with preserved ejection fraction

Abstract

Background: This prospective study was to examine the impact of right ventricular apical (RVA) pacing on atrial remodeling and function.

Methods and results: 103 patients (age 70 ± 11 years; 53 men) with preserved left ventricular (LV) ejection fraction (LVEF>45%) who received RVA pacing had Doppler echocardiography performed at baseline and after one year follow up. At one year follow up, left atrial (LA) volumes (pre-atrial contraction volume and the minimal volume) and their indexes were significantly increased with reduction in passive emptying fraction and total emptying fraction (all p<0.05). LA segmental tissue velocities - mean peak systolic (Sm-la), peak early diastolic (Em-la) and late diastolic (Am-la) - were also significantly reduced (all p<0.001). A reduction of Am-la>30% occurred in 24% of patients, and was more prevalent in patients with an elevation of LV filling pressure (E/e'>15) at one year (44.1% vs. 11.7%, χ(2)=12.75, p<0.001) as well as those with a reduction of LVEF ≥ 5% (34.0% vs. 14.3%, χ(2)=5.140, p=0.023). By multivariate regression analysis, E/e'>15 at one year (odds ratio [OR] 5.213; 95% confidence interval [CI] 1.778-15.281) and reduction of LVEF ≥ 5% (OR 3.181; 95% CI 1.045-9.686) were independent predictors of reduction of Am-la>30%.

Conclusions: Chronic RVA pacing results in LA remodeling and reduced atrial function. This is related to elevated filling pressures and impairment of LV systolic function.