Discriminative ability of left atrial strain in heart failure with mildly reduced ejection fraction

BACKGROUND: The association between left atrial reservoir strain(LASr) and outcomes remains unclear in heart failure with mildly-reduced ejection fraction(HFmrEF). We aimed to explore whether LASr offers incremental prognostic value in HFmrEF patients. METHODS: We retrospectively conducted comprehensive echocardiographic analyses in HFmrEF patients, including left ventricular(LV) and LA volumes, LVEF, early transmitral filling velocity to early diastolic mitral annular velocity(E/e'), and LA volume index(LAVi). LV global longitudinal strain(LVGLS) and LASr were analyzed using two-dimensional speckle-tracking echocardiography. The primary endpoint was a composite of HF rehospitalization(hHF) and cardiovascular death(CVD). RESULTS: The final cohort comprised 1075 patients (age, 68 ± 15 years; 61 % male) with average LVEF of 45 ± 2 %, LVGLS of 12.3 ± 2.7 %, and LASr of 16.9 ± 6.1 %. Over a median follow-up of 1.42(IQR:0.40-3.57) years, 315(29 %) patients experienced hHF or CVD. LASr was independently associated with hHF and CVD in multivariable analyses (adjusted hazard ratioaHR:0.91, 95 % confidence intervalCI:0.89-0.94, P < 0.001), even after adjustment for medications and either E/e', LAVi, or LVGLS(all P < 0.001). LASr provided incremental value in nested Cox models incorporating clinical variables, E/e', and LVGLS. Restrictive cubic spline analyses identified LASr<18 % as a threshold for elevated risk of hHF and CVD. Adjusted Kaplan-Meier analysis confirmed significantly higher event rates in patients with LASr<18 %(HR:2.23; 95 %CI:1.68-2.94; P < 0.001). LASr≥18 % demonstrated high specificity(83.8 %) and positive predictive value(87.5 %) for identifying event-free patients. CONCLUSIONS: In HFmrEF patients, LASr has a robust association with hHF and CVD, outperforming conventional echocardiography indices and LVGLS. These findings support the integration of LASr in the routine evaluation of HFmrEF, with further prospective validation warranted.