The purpose of this study is to confirm that treatment with IV ferric carboxymaltose improves exercise capacity, physical functioning and quality of life in patients with iron deficiency and chronic heart failure.

Inclusion Criteria:

• Iron deficient subjects with stable chronic heart failure (CHF) (NYHA II-III) on optimal background therapy for CHF
• Reduced exercise capacity
• Reduced left ventricular ejection fraction
• At least 18 years of age and with written informed consent prior to any study specific procedures

Exclusion Criteria:

• Erythropoietin stimulating agent (ESA) use, IV iron therapy, and/or blood transfusion in previous 6 weeks prior to randomisation
• Exercise training program(s) in the 3 months prior to screening or planned in the next 6 months
• Chronic liver disease and/or elevated liver enzymes
• Vitamin B12 and/or serum folate deficiency
• Subject is not using adequate contraceptive precautions during the study
• No other significant cardiac or general disorder that would compromise participation in the study