Normal Reference Values for Left Atrial Strain and Its Determinants from a Large Korean Multicenter Registry

Left atrial (LA) strain is a novel parameter of LA function. However, its reference value has not been established, and the determining factors for LA strain remain elusive. We aimed to present LA strain with reservoir, conduit, and contractile components and associated parameters in a large-sized group of healthy individuals.

The present study was from a prospective multicenter registry in South Korea. Subjects who had no history of cardiovascular disease with adequate images were eligible for inclusion. LA reservoir, conduit, and contractile strains (LAS_RES, LAS_CD and LAS_CT, respectively) were measured. Left ventricular global longitudinal strain (LV GLS) and early and late diastolic strain rates (DSR_e and DSR_a, respectively) were also evaluated.

Among a total of 324 subjects (mean age: 49 ± 16 years, 167 females), the mean LAS_RES, LAS_CD, and LAS_CT values were 35.9% ± 10.6%, 21.9% ± 9.3%, and 13.9% ± 3.6%, respectively. Mean LV GLS was -20.4% ± 2.2%, and mean DSR_e and DSR_a were 1.6 ± 0.4 s^-1 and 0.8 ± 0.3 s^-1, respectively. With aging, LAS_RES and LAS_CD showed significant decreases. Factors showing independent associations with LAS_RES were age (B = -0.425, p < 0.001), DSR_e (B = 4.706, p = 0.001), and LV GLS (B = -1.081, p < 0.001). Age (B = -0.319, p < 0.001), DSR_e (B = 4.140, p = 0.002), DSR_a (B = -3.409, p = 0.018), and LV GLS (B = -0.783, p < 0.001) showed associations with LAS_CD. With LAS_CT, only DSR_a showed a correlation (R = 0.277, p < 0.001).

We presented LA strain in a large-sized group of healthy subjects. Age is a significant determinant of LA function. Associations of LA strain with diastolic strain rates and LV GLS reflect cardiac mechanics.