Left Atrial Reservoir Function and Outcome in Heart Failure With Reduced Ejection Fraction: The Importance of Atrial Strain by Speckle Tracking Echocardiography

Background: Left atrial (LA) volume is a marker of cardiac remodeling and prognosis in heart failure (HF) with reduced ejection fraction (EF), but LA function is rarely measured or characterized. We investigated determinants and prognostic impact of LA reservoir function in patients with HF with reduced EF. Methods and Results: In 405 patients with stable HF with reduced EF (EF, ⩽40%) in sinus rhythm, we assessed LA reservoir function by both LA total EF (by phasic volume changes) and peak atrial longitudinal strain (PALS; by speckle tracking echocardiography); LA functional index was also calculated. During follow-up (median, 30 months; Q1–Q3, 13–52), 139 patients (34%) reached the composite end point (all-cause death/HF hospitalization). Median PALS was 15.5% (interquartile range, 11.2–20.6). By univariable analysis, all LA function parameters significantly predicted outcome (P <0.01 for all), with PALS showing the highest predictive accuracy (area under the curve, 0.75; sensitivity, 73%; specificity, 70%). Impaired PALS was associated with greater left ventricular and LA volumes, worse left ventricular EF, left ventricular global longitudinal strain, right ventricular systolic function, and more severe diastolic dysfunction. After multivariable adjustment (including LA volume and left ventricular global longitudinal strain), PALS, but not LA total EF or LA functional index, remained significantly associated with outcome (hazard ratio per 1-SD decrease, 1.38; 95% CI, 1.05–1.84; P=0.030). Adding PALS to a base model, including age, sex, LA volume, EF, E/E′ ratio, and global longitudinal strain, provided incremental predictive value (continuous net reclassification improvement, 0.449; P=0.0009). Conclusions In HF with reduced EF, assessment of LA reservoir function by PALS allows powerful prognostication, independently of LA volume and left ventricular longitudinal contraction.