Left atrial minimum volume and reservoir function as correlates of left ventricular diastolic function: impact of left ventricular systolic function.

Abstract

OBJECTIVE
Left atrial (LA) maximum volume (LAV(max)) is an indicator of left ventricular (LV) diastolic function. However, LAV(max) is also influenced by systolic events, whereas the LA minimum volume (LAV(min)) is directly exposed to LV pressure. The authors hypothesised that LAV(min) may be a better correlate of LV diastolic function than LAV(max).
DESIGN
Cross-sectional.
SETTING
University hospital.
PATIENTS
357 participants from a community-based cohort study.
METHODS
LA volumes and reservoir function, measured as total LA emptying volume (LAEV) and LA emptying fraction (LAEF), were assessed by real-time three-dimensional echocardiography. LV diastolic function was assessed by trans-mitral early (E) and late (A) Doppler velocities and mitral early diastolic velocity by tissue-Doppler (e'). LV systolic function was assessed by LV ejection fraction (LVEF) and global longitudinal strain (GLS) by speckle-tracking.
RESULTS
LAV(min) significantly increased with worsening diastolic dysfunction (p<0.001), whereas the increase in LAV(max) was less pronounced (p=0.07). LAEV and LAEF decreased with worsening diastolic dysfunction (both p<0.001). In linear regressions, LAV(min) and LAV(max) were significant predictors of E/e', with higher parameter estimates for LAV(min). In multivariate models, LAV(min) resulted strongly associated with E/e' (β=0.45, p<0.001), whereas LAV(max) was not (β=-0.16, p=0.08). LA reservoir function was better associated with GLS than LVEF. In multivariate analyses, GLS was significantly associated with LAV(max) (β=-0.15, p=0.002), LAEV (β=-0.37, p<0.001) and LAEF (β=-0.28, p<0.001) but not with LAV(min).
CONCLUSIONS
LAV(min) is a better correlate of LV diastolic function than LAV(max). The impact of LV longitudinal systolic function on LA reservoir function might explain the weaker relation between LAV(max) and LV diastolic function.