Correlations between left atrial volumes and strains in healthy adults - a three-dimensional speckle-tracking echocardiographic study

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction. Left atrium (LA) is a dynamic structure, which can be characterized by several volumetric and functional properties. Not only volumetric changes could be detected during cardiac cycle, but contractility of its walls have also special quantitative properties. Three-dimensional (3D) speckle-tracking echocardiography (3DSTE) is a new imaging technique with capability of featuring changes in both LA volume and function by several parameters based on a virtual 3D LA model respecting cardiac cycle at the same time. This ability of 3DSTE makes an opportunity to examine correlations between LA volumes and contractility features. Due to the limited number of studies assessing these physiologic relationships, the present study aimed to test correlations between LA volumes, volume-based functional properties and strains respecting cardiac cycle in healthy adults by 3DSTE. Methods. The present study comprised 217 healthy adult volunteers (mean age: 33.4 ± 12.7 years, 112 males) without any symptoms, known diseases or other states, which could affect results. None of them received any medication at the time of examination. Complete two-dimensional (2D) Doppler echocardiography and 3DSTE have been performed in all cases. Results. LA stroke volumes increased with maximum LA volume (Vmax) in reservoir, conduit and booster pump phases of LA function. LA emptying fraction (EF) remained unchanged in LA reservoir phase (total atrial EF, TAEF) with the increase in Vmax (TAEF at Vmax < 30 ml = 51.9 ± 13.7% vs. TAEF at Vmax > 50 ml = 50.9 ± 10.9%, p = ns). Significant reduction in LA-EF could be detected in LA conduit phase (passive atrial EF, PAEF), if Vmax proved to be larger than 50 ml (PAEF at Vmax < 30 ml = 34.0 ± 13.2% vs. PAEF at Vmax > 50 ml = 27.5 ± 12.6%, p < 0.05). In booster pump function LA-EF (active atrial EF, AAEF) did not show significant alterations with the increase of Vmax (AAEF at Vmax < 30 ml = 26.9 ± 14.7% vs. PAEF at Vmax > 50 ml = 31.7 ± 11.7%, p = ns). Global peak LA radial strain (RS) (at Vmax < 30 ml = -11.7 ± 8.9% vs. at 30 ml ≤ Vmax ≤ 50 ml = -15.4 ± 7.7% and at Vmax > 50 ml = -14.7 ± 6.8%, p <0.05 and p < 0.05, respectively) and 3D strain (3DS) (at Vmax < 30 ml = -5.5 ± 5.7% vs. at 30 ml ≤ Vmax ≤ 50 ml = -7.5 ± 5.6% and at Vmax > 50 ml = -8.0 ± 5.0%, p < 0.05 and p < 0.05, respectively) increased with Vmax only until a point. LA-RS and LA-3DS at atrial contraction similarly increased with Vmax. The other strain parameters did not show any changes. Conclusions. LA-RS and LA-3DS, objective features of LA contractility do not increase beyond a point in parallel with an increase in maximum LA volume in healthy subjects.