GSTM1 and hydrops fetalis: The study will be the first sufficiently powered prospective, multicenter, double-blind randomized controlled trial (RCT) to determine if intravenous FCM administered in iron-deficient stable HFrEF patients (hospitalized and re-stabilized or stable ambulatory patients with either a history of HF hospitalization or currently significantly elevated natriuretic peptides; all with left ventricular ejection fraction (LVEF) <45% and in a broad range of hemoglobin [Hb] status) compared to placebo can reduce combined rate of recurrent hospitalizations for HF and of cardiovascular death.