Abstract 12770: Left-Atrial Contractile Contribution to Left Ventricle Filling is Preserved in Moderate Chronic Heart Failure

Abstract

Introduction: The extent that left atrium (LA) functional remodeling is impacted by left ventricle (LV) systolic function or clinical history in patients with chronic heart failure (HF) is unresolved. Cardiac imaging and plasma biomarkers may provide valuable information in this regard. Hypothesis: Elastic and active contributions to LV stroke volume (LV SV) are variable, independent of LV systolic function and reflected in natriuretic peptide measurements. Methods: We recruited 27 controls without overt cardiovascular disease and 68 patients with moderate HF, including preserved and reduced LV ejection fraction (LVEF). Cardiac MRI was used to evaluate LV volumes at end diastole and end systole, and LA volumes at end diastole, diastasis and end systole to determine passive and active volume changes. Plasma mid-region pro-atrial and N-terminal pro-brain natriuretic peptides (MR-proANP and NT-proBNP, respectively) were measured. Results: Elastic LA contribution to LV SV was significantly lower in HF (median, IQR: 14%, 8-23%) than controls (24%, 17-30%; p=0.001), but active contribution was not (23%, 0-34% vs 24%, 21-31%; p=0.163). In patients with HF, active LA contribution to LV SV was negatively associated with history of hypertension (β=-0.41, p=0.007) and positively associated with aging (β=0.40, p=0.008) in a multiple linear regression model. Seven of nine subjects with HF and a history of atrial fibrillation (AF), but in sinus rhythm (SR) on the day of study, had active LA contributions to LV SV >15%. Increased LA volume at end diastole (β=0.51, p=0.001) and LVEF (β=-0.33, p=0.008) were independently associated with NT-proBNP (β=0.51, p=0.001) in a model that included age and history of AF. Similarly, LA volume at end diastole (β=0.48, p=0.001) was independently associated with MR-proANP in a model that included age and history of AF. Notably, natriuretic propeptides were not associated with elastic or active LA contributions to LV SV. Conclusions: Heart failure is characterized by preserved LA active contribution to LV SV, regardless of LVEF, which increases with age, and is modifiable by hypertension and AF. Imaging-based assessment can elucidate the contribution of LA function in HF and may provide insight into the impact of AF in patients with HF.