Effect of Intravenous Ferrous Sucrose on Exercise Capacity in Chronic Heart Failure

Inclusion Criteria: * ≥21 years of age and have signed written informed consent * Stable symptomatic CHF; NYHA III/IV and left ventricular ejection fraction (LVEF) ≤40%, or if NYHA II then LVEF must be ≤35%, as assessed within last 6 months using echocardiographic or magnetic resonance imaging techniques. * On optimal conventional therapy for at least 4 weeks prior to recruitment and without dose changes for at least 2 weeks. * Peak VO2 ≤ 18 ml/kg/min on modified Naughton protocol cardiopulmonary exercise testing. * Mean of the 2 screening Hb concentrations (week-2 and week-1) \< 12.5 g/dl (anaemic group, 50% of study population) or 12.5-14.0 g/dl (non-anaemic group, 50% of study population). * Ferritin \<100 µg/l or 100-300 µg/l with TSAT \<20%. * Normal red cell folate and vitamin B12 status (according to local lab reference range). * Resting blood pressure ≤160/100 mmHg. Exclusion Criteria: * History of acquired iron overload; known haemochromatosis or first relatives with haemochromatosis; and allergic disorders (asthma, eczema, and anaphylactic reactions). * Known hypersensitivity to parental iron preparations. * Known active infection, bleeding, malignancy and haemolytic anaemia. * History of chronic liver disease and/or alanine transaminase (ALT) or aspartate transaminase (AST) \>3 times the upper limit of the normal range; chronic lung disease; myelodysplastic disorder; and known HIV/AIDS disease. * Recipient of immunosuppressive therapy or renal dialysis. * History of erythropoietin, IV or oral iron therapy, and blood transfusion in previous 30 days. * Unstable angina pectoris, as judged by the investigator; severe uncorrected valvular disease or left ventricular outflow obstruction; obstructive cardiomyopathy; uncontrolled fast atrial fibrillation or flutter (heart rate \>110 beats per minute \[bpm\]); uncontrolled symptomatic brady- or tachyarrhythmias. * Musculoskeletal limitation that, in the judgement of the investigator, would impair cardiopulmonary exercise testing. * Pregnant or breast-feeding * Inability to comprehend study protocol * Parallel participation in another clinical trial