BackgroundIt has been reported that recovery of left ventricular ejection fraction (LVEF) is associated with better prognosis in heart failure (HF) patients with reduced EF (rEF). However, change of LVEF has not yet been investigated in cases of HF with preserved EF (HFpEF).Methods and resultsConsecutive 1082 HFpEF patients, who had been admitted to hospital due to decompensated HF (EF >50% at the first LVEF assessment at discharge), were enrolled, and LVEF was reassessed within 6 months in the outpatient setting (second LVEF assessment). Among the HFpEF patients, LVEF of 758 patients remained above 50% (pEF group), 138 patients had LVEF of 40%–49% (midrange EF, mrEF group) and 186 patients had LVEF of less than 40% (rEF group). In the multivariable logistic regression analysis, younger age and presence of higher levels of troponin I were predictors of rEF (worsened HFpEF). In the Kaplan-Meier analysis, the cardiac event rate of the groups progressively increased from pEF, mrEF to rEF (log-rank, p<0.001), whereas all-cause mortality did not significantly differ among the groups. In the multivariable Cox proportional hazard analysis, rEF (vs pEF) was not a predictor of all-cause mortality, but an independent predictor of increased cardiac event rates (HR 1.424, 95% CI 1.020 to 1.861, p=0.039).ConclusionAn initial assessment of LVEF and LVEF changes are important for deciding treatment and predicting prognosis in HFpEF patients. In addition, several confounding factors are associated with LVEF changes in worsened HFpEF patients.