La reducción temprana del filtrado glomerular se asocia con aumento de la hemoglobina tras el inicio de dapagliflozina en la insuficiencia cardiaca con fracción de eyección reducida / Early glomerular filtration rate decline is associated with hemoglobin rise following dapagliflozin initiation in heart failure with reduced ejection fraction

Introducción y objetivos: Los inhibidores del cotransportador 2 de sodio-glucosa (iSGLT2) inducen cambios a corto plazo en la función renal y la hemoglobina y su fisiopatología se comprende de manera incompleta. Nuestro objetivo es evaluar la relación entre los cambios de la tasa de filtrago glomerular estimado (TFGre) y la hemoglobina tras el inicio de dapagliflozina en pacientes estables con insuficiencia cardiaca y fracción de eyección reducida (IC-FEr). Métodos: Este análisis post hoc de un ensayo clínico aleatorizado evaluó el efecto de la dapagliflozina sobre el consumo máximo de oxígeno a 1 y 3 meses en pacientes ambulatorios con IC-FEr estable (ensayo DAPA-VO2, NCT04197635). Se utilizó un análisis de regresión lineal mixta para evaluar la relación entre los cambios en la TFGe y la hemoglobina a 1 y 3 meses. Resultados: Se evaluó a 87 pacientes. La media de edad era 67,0±10,5 años, y 21 pacientes (24,1%) eran mujeres. Las medias basales de TFGe y hemoglobina fueron de 66,9±20,7ml/min/1,73 m2 y 14,3±1,7g/dl respectivamente. En comparación con el placebo, la TFGe no cambió significativamente en el grupo de dapagliflozina, pero la hemoglobina aumentó significativamente a 1 y 3 meses. A 1 mes, el aumento de la hemoglobina se relacionó con la disminución de la TFGe solo en el grupo de dapagliflozina (p <0,001). A los 3 meses no había asociación significativa (p=0,123). Los cambios de la TFGe a 1 y 3 meses no se asociaron con cambios en el consumo pico de oxígeno, la calidad de vida o los péptidos natriuréticos. Conclusiones: En pacientes con IC-FEr estable, los cambios en la TFGe a 1 mes inducidos por la dapagliflozina están en relación inversa con cambios en la hemoglobina. Esta asociación no se observa a los 3 meses. (AU)

Introduction and objectives: Sodium-glucose cotransporter-2 inhibitors (SGLT2i) induce short-term changes in renal function and hemoglobin. Their pathophysiology is incompletely understood. We aimed to evaluate the relationship between 1- and 3-month estimated glomerular filtration rate (eGFR) and hemoglobin changes following initiation of dapagliflozin in patients with stable heart failure with reduced ejection fraction (HFrEF). Methods: This is a post hoc analysis of a randomized clinical trial that evaluated the effect of dapagliflozin on 1- and 3-month peak oxygen consumption in outpatients with stable HFrEF (DAPA-VO2 trial, NCT04197635). We used linear mixed regression analysis to assess the relationship between eGFR and hemoglobin changes across treatment arms. Results: A total of 87 patients were evaluated in this substudy. The mean age was 67.0± 10.5 years, and 21 (24.1%) were women. The mean baseline eGFR and hemoglobin were 66.9±20.7mL/min/1.73m2 and 14.3±1.7g/dL, respectively. Compared with placebo, eGFR did not significantly change at either time points in the dapagliflozin group, but hemoglobin significantly increased at 1 and 3 months. At 1 month, the hemoglobin increase was related to decreases in eGFR only in the dapagliflozin arm (P <.001). At 3 months, there was no significant association in either treatment arms (P=.123). Changes in eGFR were not associated with changes in peak oxygen consumption, quality of life, or natriuretic peptides. Conclusions: In patients with stable HFrEF, 1-month changes in eGFR induced by dapagliflozin are inversely related to changes in hemoglobin. This association was no longer significant at 3 months. (AU)

Short-Term Changes in Peak VO2 After Initiation of Dapagliflozin in Heart Failure Across Iron Status.

BACKGROUND: Some studies have indicated that sodium-glucose cotransporter-2 (SGLT2) inhibitors promote an increase in cell iron use. OBJECTIVES: The aim of this study was to examine, in patients with stable heart failure with reduced left ventricular ejection fraction (HFrEF), the effect of dapagliflozin on ferrokinetic parameters and whether short-term changes in peak oxygen consumption (Vo2) after dapagliflozin treatment are influenced by baseline and serial ferrokinetic status. METHODS: This was an exploratory analysis of a randomized, double-blind clinical trial that evaluated the effect of dapagliflozin vs placebo on peak Vo2 in patients with HFrEF (NCT04197635) and included 76 of the 90 patients initially enrolled in the trial. Changes in peak Vo2 at 1 and 3 months were explored according to baseline and longitudinal ferrokinetic parameters (natural logarithm [ln] ferritin, transferrin saturation index [TSAT], soluble transferrin receptor, and hepcidin). Linear mixed-effect regression was used for the analyses. RESULTS: Compared with placebo, dapagliflozin led to a significant decrease in 3-month ln ferritin (P = 0.040) and an increase in 1-month ln soluble transferrin receptor (P = 0.023). Between-treatment comparisons revealed a stepwise increase in peak Vo2 in the dapagliflozin group at 1 and 3 months, which was especially apparent at lower baseline values of TSAT and ferritin (P < 0.05). Lower time-varying values of TSAT (1 and 3 months) also identified patients with greater improvements in peak Vo2. CONCLUSIONS: In patients with stable HFrEF, treatment with dapagliflozin resulted in short-term increases in peak Vo2, which were most marked in patients with surrogates of greater iron deficiency at baseline and during treatment. (Short-Term Effects of Dapagliflozin on Peak Vo2 in HFrEF [DAPA-VO2]; NCT04197635).

Short-term changes in klotho and FGF23 in heart failure with reduced ejection fraction-a substudy of the DAPA-VO2 study.

The klotho and fibroblast growth factor 23 (FGF-23) pathway is implicated in cardiovascular pathophysiology. This substudy aimed to assess the changes in klotho and FGF-23 levels 1-month after dapagliflozin in patients with stable heart failure and reduced ejection fraction (HFrEF). The study included 29 patients (32.2% of the total), with 14 assigned to the placebo group and 15 to the dapagliflozin, as part of the double-blind, randomized clinical trial [DAPA-VO2 (NCT04197635)]. Blood samples were collected at baseline and after 30 days, and Klotho and FGF-23 levels were measured using ELISA Kits. Between-treatment changes (raw data) were analyzed by using the Mann-Whitney test and expressed as median (p25%-p75%). Linear regression models were utilized to analyze changes in the logarithm (log) of klotho and FGF-23. The median age was 68.3 years (60.8-72.1), with 79.3% male and 81.5% classified as NYHA II. The baseline medians of left ventricular ejection fraction, glomerular filtration rate, NT-proBNP, klotho, and FGF-23 were 35.8% (30.5-37.8), 67.4 ml/min/1.73 m2 (50.7-82.8), 1,285 pg/ml (898-2,305), 623.4 pg/ml (533.5-736.6), and 72.6 RU/ml (62.6-96.1), respectively. The baseline mean peak oxygen uptake was 13.1 ± 4.0 ml/kg/min. Compared to placebo, patients on dapagliflozin showed a significant median increase of klotho [Δ+29.5, (12.9-37.2); p = 0.009] and a non-significant decrease of FGF-23 [Δ-4.6, (-1.7 to -5.4); p = 0.051]. A significant increase in log-klotho (p = 0.011) and a decrease in log-FGF-23 (p = 0.040) were found in the inferential analysis. In conclusion, in patients with stable HFrEF, dapagliflozin led to a short-term increase in klotho and a decrease in FGF-23.

Dapagliflozin and short-term changes on circulating antigen carbohydrate 125 in heart failure with reduced ejection fraction.

Circulating antigen carbohydrate 125 (CA125) has emerged as a proxy of fluid overload in heart failure. This study aimed to evaluate the effect of dapagliflozin on short-term CA125 levels in patients with stable heart failure with reduced ejection fraction (HFrEF) and whether these changes mediated the effects on peak oxygen consumption (peakVO2). This study is a post-hoc sub-analysis of a randomized, double-blinded clinical trial in which 90 stable patients with HFrEF were randomly assigned to receive either dapagliflozin or placebo to evaluate change in peakVO2 (NCT04197635). We used linear mixed regression analysis to compare changes in the natural logarithm of CA125 (logCA125) and percent changes from baseline (Δ%CA125). We used the "rwrmed" package to perform mediation analyses. CA125 was available in 87 patients (96.7%). LogCA125 significantly decreased in patients on treatment with dapagliflozin [1-month: Δ - 0.18, (CI 95% = - 0.33 to - 0.22) and 3-month: Δ - 0.23, (CI 95% = - 0.38 to - 0.07); omnibus p-value = 0.012]. Δ%CA125 decreased by 18.4% and 31.4% at 1 and 3-month, respectively (omnibus p-value = 0.026). Changes in logCA125 mediated the effect on peakVO2 by 20.4% at 1 month (p < 0.001). We did not find significant changes for natural logarithm of NTproBNP (logNT-proBNP) [1-month: Δ - 0.03, (CI 95% = - 0.23 to 0.17; p = 0.794), and 3-month: Δ 0.73, (CI 95% = - 0.13 to 0.28; p-value 0.489), omnibus p-value = 0.567]. In conclusion, in patients with stable HFrEF, dapagliflozin resulted in a significant reduction in CA125. Dapagliflozin was not associated with short-term changes in natriuretic peptides. These changes mediated the effects on peakVO2.

Short-term Changes in Hemoglobin and Changes in Functional Status, Quality of Life and Natriuretic Peptides After Initiation of Dapagliflozin in Heart Failure With Reduced Ejection Fraction.

BACKGROUND: We aimed to evaluate the effect of dapagliflozin on short-term changes in hemoglobin in patients with stable heart failure with reduced ejection fraction (HFrEF) and whether these changes mediated the effect of dapagliflozin on functional capacity, quality of life and NT-proBNP levels. METHODS: This is an exploratory analysis of a randomized, double-blinded clinical trial in which 90 stable patients with HFrEF were randomly allocated to dapagliflozin or placebo to evaluate short-term changes in peak oxygen consumption (peak VO2) (NCT04197635). This substudy evaluated 1- and 3-month changes in hemoglobin levels and whether these changes mediated the effects of dapagliflozin on peak VO2, Minnesota Living-With-Heart-Failure test (MLHFQ) and NT-proBNP levels. RESULTS: At baseline, mean hemoglobin levels were 14.3 ± 1.7 g/dL. Hemoglobin levels significantly increased in those taking dapagliflozin (1 month: + 0.45 g/dL (P = 0.037) and 3 months:+ 0.55 g/dL (P = 0.012)]. Changes in hemoglobin levels positively mediated the changes in peak VO2 at 3 months (59.5%; P < 0.001). Changes in hemoglobin levels significantly mediated the effect of dapagliflozin in the MLHFQ at 3 months (-53.2% and -48.7%; P = 0.017) and NT-proBNP levels at 1 and 3 months (-68.0%; P = 0.048 and -62.7%; P = 0.029, respectively). CONCLUSIONS: In patients with stable HFrEF, dapagliflozin caused a short-term increase in hemoglobin levels, identifying patients with greater improvements in maximal functional capacity, quality of life and reduction of NT-proBNP levels.

Early glomerular filtration rate decline is associated with hemoglobin rise following dapagliflozin initiation in heart failure with reduced ejection fraction.

INTRODUCTION AND OBJECTIVES: Sodium-glucose cotransporter-2 inhibitors (SGLT2i) induce short-term changes in renal function and hemoglobin. Their pathophysiology is incompletely understood. We aimed to evaluate the relationship between 1- and 3-month estimated glomerular filtration rate (eGFR) and hemoglobin changes following initiation of dapagliflozin in patients with stable heart failure with reduced ejection fraction (HFrEF). METHODS: This is a post hoc analysis of a randomized clinical trial that evaluated the effect of dapagliflozin on 1- and 3-month peak oxygen consumption in outpatients with stable HFrEF (DAPA-VO2 trial, NCT04197635). We used linear mixed regression analysis to assess the relationship between eGFR and hemoglobin changes across treatment arms. RESULTS: A total of 87 patients were evaluated in this substudy. The mean age was 67.0± 10.5 years, and 21 (24.1%) were women. The mean baseline eGFR and hemoglobin were 66.9±20.7mL/min/1.73m2 and 14.3±1.7g/dL, respectively. Compared with placebo, eGFR did not significantly change at either time points in the dapagliflozin group, but hemoglobin significantly increased at 1 and 3 months. At 1 month, the hemoglobin increase was related to decreases in eGFR only in the dapagliflozin arm (P <.001). At 3 months, there was no significant association in either treatment arms (P=.123). Changes in eGFR were not associated with changes in peak oxygen consumption, quality of life, or natriuretic peptides. CONCLUSIONS: In patients with stable HFrEF, 1-month changes in eGFR induced by dapagliflozin are inversely related to changes in hemoglobin. This association was no longer significant at 3 months.

Bending oxygen saturation index and risk of worsening heart failure events in chronic heart failure.

AIMS: Bendopnea is a clinical symptom of advanced heart failure with uncertain prognostic value. We aimed to evaluate whether bendopnea and the change in oxygen saturation when bending forward (bending oxygen saturation index [BOSI]) are associated with adverse outcomes in ambulatory chronic heart failure (CHF) patients. METHODS AND RESULTS: We prospectively evaluated 440 subjects with symptomatic CHF. BOSI was defined as the difference between sitting and bending oxygen saturation (SpO2 ). The endpoint was the total number of worsening heart failure (WHF) events (heart failure hospitalization or urgent heart failure visit requiring parenteral diuretic therapy). The mean age was 74 ± 10 years, 257 (58.6%) were male, and 226 (51.4%) had a left ventricular ejection fraction <50%. Bendopnea was present in 94 (21.4%) patients, and 120 (27.3%) patients had a BOSI ≥-3%. The agreement between BOSI ≥-3% and bendopnea was moderate (Gwet's AC 0.482, p < 0.001). At a median (p25%-p75%) follow-up of 2.17 years (0.88-3.16), we registered 441 WHF events in 148 patients. After multivariable adjustment, BOSI was independently associated with the risk for total WHF episodes (overall, p < 0.001). Compared to improvement/no change in SpO2 when bending (BOSI 0%), those with BOSI ≥-3% showed an increased risk of WHF events (incidence rate ratio [IRR] 2.16, 95% confidence interval [CI] 1.67-2.79; p < 0.001). In contrast, bendopnea was not associated with the risk of total WHF episodes (IRR 1.04, 95% CI 0.83-1.31; p = 0.705). CONCLUSIONS: In ambulatory and stable CHF patients, BOSI ≥-3% and not bendopnea was independently associated with an increased risk of total (first and recurrent) WHF episodes. Awareness of SpO2 while assessing bendopnea may be a useful tool for predicting heart failure decompensations.

Short-term effects of dapagliflozin on maximal functional capacity in heart failure with reduced ejection fraction (DAPA-VO2 ): a randomized clinical trial.

AIMS: This study aimed to evaluate the effect of dapagliflozin on 1 and 3-month maximal functional capacity in patients with stable heart failure with reduced ejection fraction (HFrEF). METHODS AND RESULTS: In this multicentre, randomized, double-blind clinical trial, 90 stable patients with HFrEF were randomly assigned to receive either dapagliflozin (n = 45) or placebo (n = 45). The primary outcome was a change in peak oxygen consumption (peakVO2 ) at 1 and 3 months. Secondary endpoints were changes at 1 and 3 months in 6-min walk test (6MWT) distance, quality of life (Minnesota Living with Heart Failure Questionnaire [MLHFQ]), and echocardiographic parameters (diastolic function, left chamber volumes, and left ventricular ejection fraction). We used linear mixed regression analysis to compare endpoint changes. Estimates were adjusted for multiple comparisons. The mean age was 67.1 ± 10.7 years, 69 (76.7%) were men, 29 (32.2%) had type 2 diabetes, and 80 (88.9%) were in New York Heart Association class II. Baseline means of peakVO2 , 6MWT and MLHFQ were 13.2 ± 3.5 ml/kg/min, 363 ± 110 m, and 23.1 ± 16.2, respectively. The median (25th-75th percentile) of N-terminal pro-brain natriuretic peptide was 1221 pg/ml (889-2100). Most patients were on treatment with sacubitril/valsartan (88.9%), beta-blockers (91.1%), and mineralocorticoid receptor antagonists (74.4%). PeakVO2 significantly increased in patients on treatment with dapagliflozin (1 month: +Δ 1.09 ml/kg/min, 95% confidence interval [CI] 0.14-2.04; p = 0.021, and 3 months: +Δ 1.06 ml/kg/min, 95% CI 0.07-2.04; p = 0.032). Similar positive findings were found when evaluating changes from baseline. No significant differences were observed in secondary endpoints. CONCLUSIONS: Among patients with stable HFrEF, dapagliflozin resulted in a significant improvement in peakVO2 at 1 and 3 months. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04197635.

Rehospitalization burden and morbidity risk in patients with heart failure with mid-range ejection fraction.

AIMS: Heart failure with mid-range ejection fraction (HFmrEF) has been proposed as a distinct HF phenotype, but whether patients on this category fare worse, similarly, or better than those with HF with reduced EF (HFrEF) or preserved EF (HFpEF) in terms of rehospitalization risks over time remains unclear. METHODS AND RESULTS: We prospectively included 2961 consecutive patients admitted for acute HF (AHF) in our institution. Of them, 158 patients died during the index admission, leaving the sample size to be 2803 patients. Patients were categorized according to their EF: HFrEF if EF ≤ 40% (n = 908, 32.4%); HFmrEF if EF = 41-49% (n = 449, 16.0%); and HFpEF if EF ≥ 50% (n = 1446, 51.6%). Covariate-adjusted incidence rate ratios (IRRs) were used to evaluate the association between EF status and recurrent all-cause and HF-related admissions. At a median follow-up of 2.6 years (inter-quartile range: 1.0-5.3), 1663 (59.3%) patients died, and 6035 all-cause readmissions were registered in 2026 patients (72.3%), 2163 of them HF related. Rates of all-cause readmission per 100 patients-years of follow-up were 150.1, 176.9, and 163.6 in HFrEF, HFmrEF, and HFpEF, respectively (P = 0.097). After multivariable adjustment, when compared with that of patients with HFrEF and HFpEF, HFmrEF status was not significantly associated with a different risk of all-cause readmissions (IRR = 0.99; 95% confidence interval [CI], 0.77-1.27; P = 0.926; and IRR = 0.93; 95% CI, 0.74-1.18; P = 0.621, respectively) or HF-related readmissions (IRR = 1.06; 95% CI, 0.77-1.46; P = 0.725; and IRR = 1.11; 95% CI, 0.82-1.50; P = 0.511, respectively). CONCLUSIONS: Following an admission for AHF, patients with HFmrEF had a similar rehospitalization burden and a similar risk of recurrent all-cause and HF-related admissions than had patients with HFrEF or HFpEF. Regarding morbidity risk, HFmrEF seems not to be a distinct HF phenotype.

Right Ventricular Dysfunction Staging System for Mortality Risk Stratification in Heart Failure With Preserved Ejection Fraction.

Right ventricular dysfunction (RVD) parameters are increasingly important features in heart failure with preserved ejection fraction (HFpEF). We sought to evaluate the prognostic impact of a progressive RVD staging system by combining the tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (TAPSE/PASP) ratio with functional tricuspid regurgitation (TR) severity. We prospectively included 1355 consecutive HFpEF patients discharged for acute heart failure (HF). Of them, in 471 (34.7%) patients, PASP could not be accurately measured, leaving the final sample size to be 884 patients. Patients were categorized as Stage 1: TAPSE/PASP ≥ 0.36 without significant TR; stage 2: TAPSE/PASP ≥ 0.36 with significant TR; stage 3: TAPSE/PASP < 0.36 without significant TR; and stage 4: TAPSE/PASP < 0.36 with significant TR. By the 1 year follow-up, 207 (23.4%) patients had died. We found a significant and graded association between RVD stages and mortality rates (15.8%, 25%, 31.2%, and 45.4% from stage 1 to stage 4, respectively; log-rank test, p < 0.001). After multivariable adjustment, and compared to stage 1, stages 3 and 4 were independently associated with mortality risk (HR: 1.8219; 95% CI 1.308-2.538; p < 0.001 and HR = 2.2632; 95% CI 1.540-3.325; p < 0.001, respectively). A RVD staging system, integrating TAPSE/PASP and TR, provides a comprehensive and widely available tool for risk stratification in HFpEF.

Noninvasive Imaging Estimation of Myocardial Iron Repletion Following Administration of Intravenous Iron: The Myocardial-IRON Trial.

Background Intravenous ferric carboxymaltose (FCM) improves symptoms, functional capacity, and quality of life in heart failure and iron deficiency. The mechanisms underlying these effects are not fully understood. The aim of this study was to examine changes in myocardial iron content after FCM administration in patients with heart failure and iron deficiency using cardiac magnetic resonance. Methods and Results Fifty-three stable heart failure and iron deficiency patients were randomly assigned 1:1 to receive intravenous FCM or placebo in a multicenter, double-blind study. T2* and T1 mapping cardiac magnetic resonance sequences, noninvasive surrogates of intramyocardial iron, were evaluated before and 7 and 30 days after randomization using linear mixed regression analysis. Results are presented as least-square means with 95% CI. The primary end point was the change in T2* and T1 mapping at 7 and 30 days. Median age was 73 (65-78) years, with N-terminal pro-B-type natriuretic peptide, ferritin, and transferrin saturation medians of 1690 pg/mL (1010-2828), 63 ng/mL (22-114), and 15.7% (11.0-19.2), respectively. Baseline T2* and T1 mapping values did not significantly differ across treatment arms. On day 7, both T2* and T1 mapping (ms) were significantly lower in the FCM arm (36.6 [34.6-38.7] versus 40 [38-42.1], P=0.025; 1061 [1051-1072] versus 1085 [1074-1095], P=0.001, respectively). A similar reduction was found at 30 days for T2* (36.3 [34.1-38.5] versus 41.1 [38.9-43.4], P=0.003), but not for T1 mapping (1075 [1065-1085] versus 1079 [1069-1089], P=0.577). Conclusions In patients with heart failure and iron deficiency, FCM administration was associated with changes in the T2* and T1 mapping cardiac magnetic resonance sequences, indicative of myocardial iron repletion. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT03398681.

Iron deficiency and long-term mortality in elderly patients with acute coronary syndrome.

AIM: We evaluated the relationship between iron deficiency (ID) and long-term mortality risk in elderly patients with acute coronary syndrome (ACS). METHODS: In this prospective observational study, we included 252 patients older than 65 years with ACS. Transferrin saturation (TSAT) and ferritin were collected before discharge. RESULTS: Mean age, hemoglobin and GRACE score were 78 ± 7 years, 12.4 ± 1.8 g/dl and 138.8 ± 25.3, respectively, 112(44.4%) patients were women, and 151(59.9%) presented ID. During the follow-up, 121 (48%) patients died. Mortality rates among TSAT quartiles were: 2.38, 1.60, 0.90 and 0.95 × 10 person-years for Q1TSAT to Q4TSAT, respectively (p < 0.001) and did not differ across ferritin quartiles (p = 0.601), whereas ID definition was borderline associated (p = 0.060). Adjusted TSAT levels remained inverse, nonlinearly associated with long-term mortality risk (p < 0.001), with an exponential increased-risk from values about 20% and below. CONCLUSION: Lower TSAT levels were independently associated with increased mortality risk in these patients.

Changes in myocardial iron content following administration of intravenous iron (Myocardial-IRON): Study design.

Treatment with intravenous ferric carboxymaltose (FCM) has been shown to improve symptoms, functional capacity, and quality of life in patients with heart failure and iron deficiency. However, the underlying mechanisms for these beneficial effects remain undetermined. The aim of this study is to quantify cardiac magnetic resonance changes in myocardial iron content after administration of intravenous FCM in patients with heart failure and iron deficiency and contrast them with parameters of heart failure severity. This is a multicenter, double-blind, randomized study. Fifty patients with stable symptomatic heart failure, left ventricular ejection fraction <50%, and iron deficiency will be randomly assigned 1:1 to receive intravenous FCM or placebo. Intramyocardial iron will be evaluated by T2* and T1 mapping cardiac magnetic resonance sequences before and at 7 and 30 days after FCM. After 30 days, patients assigned to placebo will receive intravenous FCM in case of persistent iron deficiency. The main endpoint will be changes from baseline in myocardial iron content at 7 and 30 days. Secondary endpoints will include the correlation of these changes with left ventricular ejection fraction, functional capacity, quality of life, and cardiac biomarkers. The results of this study will add important knowledge about the effects of intravenous FCM on myocardial tissue and cardiac function. We hypothesize that short-term (7 and 30 days) myocardial iron content changes after intravenous FCM, evaluated by cardiac magnetic resonance, will correlate with simultaneous changes in parameters of heart failure severity. The study is registered at http://www.clinicaltrials.gov (NCT03398681).