The authors sought to determine whether global longitudinal strain (GLS) is independently associated with the natural history of patients with heart failure (HF) with improved ejection fraction (HFimpEF).Left ventricular (LV) ejection fraction (EF) often improves in patients with reduced EF. The clinical course of patients with HFimpEF, however, is quite variable. GLS, a sensitive indicator of LV systolic function, could help predict risk of future events in this population.Retrospective analysis of HF patients with LVEF40% on index echocardiogram who had LVEF 40% on initial study and improvement of ≥10%. GLS was assessed by 2-dimensional speckle-tracking software on index echocardiography. Primary outcome was time to first occurrence of cardiovascular mortality or HF hospitalization/emergency treatment.Of the 289 patients with HFimpEF, median absolute values of GLS (aGLS) and LVEF from index echocardiography were 12.7% (IQR: 10.8%-14.7%) and 52% (IQR: 46%-58%), respectively. Over 53 months following index echocardiography, the primary endpoint occurred less frequently in patients with aGLS above the median than below it (21% vs 34%; P = 0.014); HR of 0.51; 95% CI: 0.33-0.81; P = 0.004. When assessed as a continuous variable, each 1% increase in aGLS on index echocardiogram was associated with a lower likelihood of the composite endpoint; HR of 0.86; 95% CI: 0.79-0.93; P 0.001, an association that persisted after multivariable adjustment; HR 0.90; 95% CI: 0.82-0.97; P = 0.01. Lower aGLS was associated with increased likelihood of deterioration in LVEF.In patients with HFimpEF, GLS is a strong predictor for future HF events and deterioration in cardiac function.