Integrating Left Atrial Reservoir Strain into the First-line Assessment of Diastolic Function: Prognostic Implications in a Community-Based Cohort With Normal Left Ventricular Systolic Function.

Background: Left atrial reservoir strain (LASr) has emerged as a sensitive marker of LA function and elevated filling pressures, even though its role in detecting diastolic dysfunction (DD) and the subsequent risk stratification has remained relatively underexplored. Accordingly, we aimed to investigate the prognostic implications of replacing left atrial volume index (LAVi) with LASr in the 2016 ASE/EACVI algorithm for diagnosing DD, compared to the 2024 BSE algorithm, in individuals with normal left ventricular (LV) systolic function.

Methods: We retrospectively identified 1180 volunteers from a population-based screening program with normal LV systolic function and no evidence of myocardial disease. Echocardiographic measurements comprised recommended parameters of diastolic function and LASr by speckle tracking. Diastolic function was assessed using the BSE algorithm and the modified ASE/EACVI algorithm, in which LAVi >34 ml/m² was replaced with LASr <23%. The primary endpoint was the composite of all-cause mortality and heart failure hospitalization.

Results: During a median follow-up of 11 years, 133 (11%) individuals met the primary endpoint. Using the BSE algorithm, there was no difference in the risk of meeting the primary endpoint between individuals with normal diastolic function and those with impaired diastolic function with normal filling pressures. In univariable analysis, individuals having impaired diastolic function with elevated filling pressures exhibited a significantly higher risk than those in the other two groups (unadjusted HRs: 4.408 [95% CI: 2.376 - 8.179], p<0.001, and 5.137 [95% CI: 1.138 - 23.181], p=0.033, respectively). However, these differences were no longer significant after adjusting for relevant covariates. In contrast, the modified ASE/EACVI algorithm identified three groups with distinct risk profiles, and even in multivariable analysis, individuals with DD had a higher risk of meeting the primary endpoint than those with normal diastolic function (adjusted HR: 3.199 [95% CI: 1.534 - 6.671], p=0.002).

Conclusion: In a community-based cohort with normal LV function, integrating LASr into the first-line echocardiographic assessment of diastolic function improved both classification and subsequent risk stratification.