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

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.

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).

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 ratio[aHR]:0.91, 95 % confidence interval[CI]: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.

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.