Left atrial contractile longitudinal strain determines intrinsic left atrial function regardless of load status and left ventricular deformation.

Purpose: Left atrial (LA) longitudinal strain (S) has been proposed as a superior, non-invasive parameter over LA volumetric assessment. LAS has diagnostic and prognostic value in many cardiovascular pathologies. Nevertheless, the acute effect of hemodynamic changes on LAS indices is not well-established. We sought to identify volume independent physiomechanical changes in LA and interrelation between LA and left ventricular (LV) strain indices following a large amount of fluid loss provided by hemodialysis.

Methods: Seventy-five patients between 18 and 85 years of age under hemodialysis therapy were included. The echocardiographic images were obtained before and after hemodialysis. Phasic LAS and LV global longitudinal strain (GLS) were calculated. The impact of volume depletion on echocardiographic measurements and their temporal correlation were calculated.

Results: LV and LA dimensions,volumes and LV, LA reservoir, and conduit deformation showed a significant decrease after hemodialysis. No significant change was observed for LAS (p = 0.203). The ultrafiltrated volume was significantly correlated with the changes in LVGLS (r = 0.75, p < 0.001), and LAS (r = 0.81, p < 0.001) and LA total emptying volume (r = 0.80, p < 0.001). Absolute changes in LAS and LVGLS were strongly correlated (r = 0.83, p < 0.001). There was no correlation between absolute changes in LAS and LVGLS or ultrafiltrated volume (p = NS, both).

Conclusion: LA reservoir and conduit LS are highly volume dependent strain parameters and are strongly correlated with LV deformation along with ultrafiltrated volume. Acute excessive volume depletion or LV deformation have no influence on LAS. It is important to identify independent easily accessible functional parameters for the LA which would improve clinical evaluation.