Recovered Left Ventricular Ejection Fraction and Its Prognostic Impacts in Hospitalized Heart Failure Patients with Reduced Ejection Fraction.

It has been recently recognized that recovery of left ventricular ejection fraction (EF), termed "recovered EF", occurs in a proportion of heart failure patients with reduced EF (HFrEF), and is associated with better prognosis. However, the clinical characteristics of "recovered EF" have not been fully examined.Consecutive 567 patients hospitalized due to HFrEF (EF < 40% at 1st assessment at hospital discharge) were enrolled, and EF was re-assessed within half a year in an outpatient setting (2nd assessment). Among these HFrEF patients, 235 remained EF < 40% (reduced, rEF group), 82 changed to EF 40-49% (midrange, mrEF group), and 250 recovered to EF > 50% (preserved, pEF group "recovered EF" ) at the 2nd examination. Age was lower and body mass index and systolic blood pressure were higher in pEF than in rEF. The prevalence of atrial fibrillation (AF) and usage of an implantable cardiac defibrillator and cardiac resynchronization therapy were highest in pEF. Left ventricular end diastolic dimension (LVDd) was the smallest in the pEF group. Multivariable logistic regression analysis revealed that younger age, presence of AF, and lower levels of LVDd were predictors of "recovered EF". Kaplan-Meier analysis found that pEF presented the lowest cardiac event rate (P = 0.003) and all-cause mortality (P = 0.001). In multivariable Cox proportional hazard analyses, pEF (versus rEF) was an independent predictor of both cardiac event rate (HR = 0.668, 95%CI 0.450-0.994, P = 0.046) and all-cause mortality (HR = 0.655, 95%CI 0.459-0.934, P = 0.019).Hospitalized HFrEF patients with recovered EF are associated with younger age, higher presence of AF, and better prognosis.