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

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.