There are multiple definitions:

1. left atrial sphericity index(English)

   • LA
   • Cardiology, Bioengineering
   • https://doi.org…io.2023.5.n2158

2. left atrial stiffness index(English)

   • defined as the ratio of the average E/e’ to LASr. Closely associated with LV filling pressure and LV diastolic function
   • HFpEF, LACI, LASr, LAVI, LVEDV, E/e'
   • Cardiology, Bioengineering, Ratio-based metric
   • https://doi.org…cho.2025.05.009
   • https://doi.org…cho.2025.04.011