The effect of iron deficiency treatment with intravenous ferric carboxymaltose on the arrhythmic burden of patients with HFrEF and cardiac implantable electronic devices

Abstract

Abstract Background The deleterious effect of iron deficiency (ID) on cardiomyocyte electrochemical stability is well-documented. In patients with heart failure and reduced ejection fraction (HFrEF), ID represents a key comorbidity associated with increased morbidity and mortality. Thus, it has been hypothesized that treating ID may lead to reduced incidence of arrhythmias in HFrEF patients. Purpose To study the effect of intravenous ferric carboxymaltose (IV FCM) treatment on the iron stores, arrhythmic burden, functional capacity and quality of life in HFrEF patients with ID and cardiac implantable electronic devices (CIEDs). Methods Patients with HFrEF, ID and CIEDs scheduled to receive IV FCM as per ESC guidelines were invited to participate. Follow-up lasted 12 months. The primary outcome was related to the amelioration of patients’ iron status. Secondary outcomes relative to arrhythmic burden included (i) the incidence of device-detected ventricular tachycardias (VTs) between the year before recruitment to the study and the follow-up period, (ii) patients’ Lown and Wolf classification as derived from 24hour Holter monitoring. Data related to non-invasive arrhythmic markers such as late potential, microvolt T-wave alternans and deceleration capacity were also available. Results This real-life cohort included 79 patients (84% male). Patients’ median age was 70.8 [IRQ:11.7] years. Median ferritin increased to 150 [125] ng/mL at 12 months (baseline 55 [68] ng/mL, P<0.001). At their final visit, 45 (57%) patients no longer met the ESC criteria for iron deficiency (P<0.001). The CIED-derived incidence of VT episodes decreased significantly after 12 months of IV FCM treatment (0.26±0.83 episodes per patient per year compared to 0.8±2.36, P = 0.048). Patients were also significantly likely to shift to a more favorable Lown and Wolf arrhythmic burden classification (P = 0.01). Patients’ late potential results and microvolt T-wave alternans also improved significantly (P = 0.01 for both tests). Conclusion The results of this real-life cohort analysis suggest significant reduction of the arrhythmic burden in HFrEF and ID after restitution of iron stores. Further studies are needed to further evaluate the impact of these results.