Background:Heart failure (HF) is often associated with iron deficiency (ID). Skeletal muscle abnormalities are common in HF, but the potential role of ID in this phenomenon is unclear. In addition to hemopoiesis, iron is essential for muscle bioenergetics. We examined whether energetic abnormalities in skeletal muscle in HF are affected by ID and if they are responsive to intravenous iron.Methods and Results:Forty-four chronic HF subjects and 25 similar healthy volunteers underwent ³¹P magnetic resonance spectroscopy of calf muscle at rest and during exercise (plantar flexions). Results were compared between HF subjects with or without ID. In 13 ID-HF subjects, examinations were repeated 1 month after intravenous ferric carboxymaltose administration (1000 mg). As compared with controls, HF subjects displayed lower resting high-energy phosphate content, lower exercise pH, and slower postexercise PCr recovery. Compared with non-ID HF, ID-HF subjects had lower muscle strength, larger PCr depletion, and more profound intracellular acidosis with exercise, consistent with an earlier metabolic shift to anaerobic glycolysis. The exercise-induced PCr drop strongly correlated with pH change in HF group (r=−0.71, P<0.001) but not in controls (r=0.13, P=0.61, interaction: P<0.0001). Short-term iron administration corrected the iron deficit but had no effect on muscle bioenergetics assessed 1 month later.Conclusions:HF patients display skeletal muscle myopathy that is more severe in those with iron deficiency. The presence of ID is associated with greater acidosis with exercise, which may explain early muscle fatigue. Further study is warranted to identify the strategy to restore iron content in skeletal muscle.

中文翻译：

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慢性心力衰竭的骨骼肌异常和铁缺乏症

背景：心力衰竭（HF）通常与铁缺乏症（ID）相关。骨骼肌异常在HF中很常见，但ID在这种现象中的潜在作用尚不清楚。除造血作用外，铁对于肌肉生物能也是必不可少的。方法和结果：44名慢性HF受试者和25名类似的健康志愿者接受了^{31次研究。}小腿肌肉在静止和运动过程中的P磁共振波谱（足底弯曲）。比较有或没有ID的HF受试者的结果。在13名ID-HF受试者中，在静脉内施用羧甲基麦芽糖铁（1000 mg）后1个月重复检查。与对照组相比，HF患者的静息高能磷酸盐含量较低，运动pH较低，运动后PCr的恢复较慢。与非ID HF相比，ID-HF受试者的肌肉强度更低，PCr消耗更大，运动时细胞内酸中毒更严重，这与较早的代谢转变为厌氧糖酵解相一致。运动诱发的PCr下降与HF组的pH变化密切相关（r = -0.71，P <0.001），而与对照组无关（r＝ 0.13，P＝ 0.61，相互作用：P＜0.0001）。短期铁剂治疗可纠正铁缺乏症，但对1个月后评估的肌肉生物能学无影响。结论：HF患者显示骨骼肌肌病，铁缺乏症患者更为严重。ID的存在与运动中酸中毒的增加有关，这可以解释早期的肌肉疲劳。有必要进行进一步的研究以确定恢复骨骼肌中铁含量的策略。