The Predictive Power of Left Atrial Reservoir Strain for Long-Term Atrial Fibrillation in The Atherosclerosis Risk in Communities (ARIC) Study.

Background: Left atrial (LA) function measures from the two-dimensional echocardiograms are linked to atrial fibrillation (AF) development, but their standalone predictive value remains unclear.

Objective: This study assessed the standalone predictive power of LA function measures for long-term AF prediction (5 and 10 years).

Methods: We analyzed 5,442 older adults (median age 74) from the Atherosclerosis Risk in Communities (ARIC) study without prior AF. Participants were split into training and testing sets (7:3 ratio). We evaluated the standalone predictive performance of LA strain measures (reservoir, conduit, and contraction strain) with and without age for long-term AF. The performance was compared to that of the CHARGE-AF score and a machine learning-based predictive model that incorporates the most important routinely measured echocardiographic parameters with LA strain measures.

Results: LA reservoir strain alone achieved a Harrell's C-index of 0.664 and 0.646 for 5- and 10-year AF prediction, improving to 0.677 and 0.663 when combined with age, which outperformed the CHARGE-AF score (0.667 and 0.655) and other LA strain measures. A better predictive performance was achieved by the machine learning-based predictive model, including LA reservoir strain, age, race, and 9 echocardiographic parameter; the C-indexes were 0.732 (0.686-0.777) for 5-year and 0.725 (0.693-0.757) for 10-year prediction.

Conclusion: The standalone predictive performance of LA reservoir strain for long-term AF risk is comparable to CHARGE-AF score (11 variables) and slightly lower than that of a machine learning-based model with 12 variables, highlighting the importance of LA reservoir in AF risk prediction.