The predictive power of left atrial reservoir strain for long-term atrial fibrillation in the Atherosclerosis Risk in Communities study

Background Left atrial (LA) function measures from the 2-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 5442 older adults (median age 74) from the Atherosclerosis Risk in Communities study without previous 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 with 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 parameters; 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 with the 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.