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

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.