Oral Iron Repletion Effects On Oxygen Uptake in Heart Failure

Therapeutic options to further improve functional capacity and symptoms in HF beyond neurohormonal antagonism are limited. Studies have demonstrated impaired oxidative capacity of skeletal muscle among HF patients, which may contribute to symptoms of breathlessness and persistent fatigue. In addition to its role in erythropoiesis, iron (Fe) plays a critical role in skeletal muscle's oxygen (O2)-storage capacity (myoglobin) and systemic aerobic energy production. As Fe deficiency is common in patients with symptomatic HF, repletion of iron stores may improve submaximal exercise capacity among these patients beyond the effects on erythropoiesis. While intravenous Fe repletion in HF patients with mild Fe-deficiency (i.e. Ferritin \<100 or Ferritin 100-299 with transferrin saturation \<20%) with or without anemia global well-being and functional status, oral Fe repletion has not been studied. Furthermore, the efficacy of oral Fe to replete iron stores in a similar population and its impact on functional capacity, measured objectively by peak VO2, remains unknown.