Impact of Intravenous Iron Repletion On Mechanisms of Exercise InTolerance in HFpEF (IRONMET-HFpEF)

The primary objective of this study is to determine if the correction of functional iron deficiency by administering a single dose of intravenous iron (ferric derimaltose or Monoferric®) in participants with heart failure with preserved ejection fraction (HFpEF) will improve exercise capacity as measured by the change in peak oxygen uptake (peak VO2) from baseline to 12 weeks.

Inclusion Criteria: 1. Adult (≥18 years of age) able to provide informed consent. 2. Stable heart failure (NYHA II-IV) for at least 4 weeks 3. Heart Failure with Preserved left ventricular ejection fraction.(Left ventricular ejection fraction ≥ 50 % obtained within 6 months of informed consent. 4. NT-proBNP ≥ 125 pg/mL without ongoing atrial fibrillation/flutter. If ongoing atrial fibrillation/flutter at the time of sample collection, NT-proBNP must be ≥ 250 pg/mL OR patients must have a history of pulmonary capillary wedge pressure ≥ 15 mm Hg during rest or the slope of pulmonary capillary wedge pressure to cardiac output (PCWP/CO) ≥ 2.0 mmHg/L/min during upright exercise (Eisman et al., Circ Heart Fail. 2018 May;11(5):e004750.).OR subjects must have a heart failure hospitalization within the last 12 months prior to screening OR Chronic diastolic dysfunction on echocardiography as evidenced by: Left Atrial Enlargement (LAE): LA diameter ≥ 3.8cm in women, ≥ 4.0 cm in men or LA length ≥ 5.0 cm or LA area ≥ 20 cm2 OR LA volume ≥ 55mL or LA volume index ≥ 29ml/m2 or Left Ventricular Hypertrophy (LVH): septal thickness or posterior wall thickness ≥ 1.1 cm OR For patients in sinus rhythm: E/e' ratio ≥15 at septal annulus, or E/e' ratio ³13 at lateral annulus, or average E/e' ratio ³14. For patients in atrial fibrillation: E/e' ≥ 11 at the septal annulus. 5. Hemoglobin \>9.0 g/dL AND \