Left atrial strain in patients without cardiovascular disease: uncovering influencing and related factors.

Background: Despite its proven prognostic value in different contexts, the precise implications of left atrial strain (LAS) assessment throughout different phases of the atrial cycle remain uncertain. A direct correlation between left atrial reservoir strain (LARS) and left ventricular global longitudinal strain (GLS) has been consistently demonstrated in several studies involving patients with various heart diseases. The objective of our study is to identify factors directly associated with LARS, left atrial conduction strain (LACS) and left atrial booster strain (LABS) in patients without cardiovascular (CV) disease.

Methods: Transthoracic echocardiographic examinations in patients without CV disease were prospectively selected in two tertiary hospitals echocardiography labs for clinical purposes. LAS, maximal and minimal left atrial (LA) volumes and left atrial ejection fraction (LAEF) were measured using the two-dimensional strain analysis package provided by the EchoPAC Plugging workstation (AFI LA).

Results: A total of 196 cases were included, median age of 54 (45-62) with 85 (43%) being men. The mean left ventricular ejection fraction (LVEF) was 61% ± 5, and the median GLS was - 18% (-17 to -20). Median indexed maximum volume of left atrium (LAVI) was 27 ml/m (22-31), and LAEF was 64% (58-70). The mean LARS biplane was 35,1% ± 8. Notably, LARS was greater in the 2-chamber view (36,1% ± 10) compared to the 4-chamber view (34,1% ± 8 p < 0,05). The multivariate analysis of LARS revealed that sex, GLS, LAEF and e' are independently correlated with LARS. Multivariate analysis of LACS showed independent correlations between LACS and age, GLS, LAEF, E/A ratio and e'. Conversely, the multivariate analysis of LABS demonstrated significant correlations among A wave, e', and left atrial stiffness index (LASI).

Conclusions: In patients without CV disease, GLS emerges as a crucial determinant of LARS and LACS. LAEF and e' are directly and independently related to both LARS and LACS. LARS (univariate) and LACS (multivariate) exhibited a decline with older age in individuals without CV disease.