Increased iron stores prolong the QT interval - a general population study including 20 261 individuals and meta-analysis of thalassaemia major

Ferroptosis mechanisms and regulations in cardiovascular diseases in the past, present, and future

Cardiovascular diseases (CVDs) are the main diseases that endanger human health, and their risk factors contribute to high morbidity and a high rate of hospitalization. Cell death is the most important pathophysiology in CVDs. As one of the cell death mechanisms, ferroptosis is a new form of regulated cell death (RCD) that broadly participates in CVDs (such as myocardial infarction, heart transplantation, atherosclerosis, heart failure, ischaemia/reperfusion (I/R) injury, atrial fibrillation, cardiomyopathy (radiation-induced cardiomyopathy, diabetes cardiomyopathy, sepsis-induced cardiac injury, doxorubicin-induced cardiac injury, iron overload cardiomyopathy, and hypertrophic cardiomyopathy), and pulmonary arterial hypertension), involving in iron regulation, metabolic mechanism and lipid peroxidation. This article reviews recent research on the mechanism and regulation of ferroptosis and its relationship with the occurrence and treatment of CVDs, aiming to provide new ideas and treatment targets for the clinical diagnosis and treatment of CVDs by clarifying the latest progress in CVDs research.

Electrophysiological properties and heart rate variability of patients with thalassemia major in Jakarta, Indonesia

Beta thalassemia major (TM) is a common hereditary disease in Indonesia. Iron overload due to regular transfusion may induce myocardial iron deposition leading to electrophysiological dysfunction and functional disorders of the heart. Ventricular arrhythmia is one of the most common causes of sudden cardiac death in thalassemia patients. This cross-sectional study of 62 TM patients aged 10-32 years in Cipto Mangunkusumo General Hospital was done to assess their electrophysiological properties and heart rate variability, including 24- hour Holter monitoring, signal averaged electrocardiogram (SAECG) for detection of ventricular late potential (VLP), and determination of heart rate variability (HRV). We also assessed their 12-lead ECG parameters, such as P wave, QRS complex, QT/ QTc interval, QRS dispersion, and QT/ QTc dispersion. Iron overload was defined by T2-star magnetic resonance (MR-T2*) values of less than 20 ms or ferritin level greater than 2500 ng/mL. Subjects were grouped accordingly. There were significant differences of QTc dispersion (p = 0.026) and deceleration capacity (p = 0.007) between MR-T2* groups. Multivariate analysis showed an inverse correlation between QTc dispersion and MR-T2* values. There was a proportional correlation between heart rate deceleration capacity in the low MR-T2* group (p = 0.058) and the high ferritin group (p = 0.007). No VLPs were detectable in any patients. In conclusion, prolonged QTc dispersion and decreased heart rate deceleration capacity were significantly correlated with greater odds of iron overload among patients with Thalassemia major.

Iron in Cardiovascular Disease: Challenges and Potentials

Iron is essential for many biological processes. Inadequate or excess amount of body iron can result in various pathological consequences. The pathological roles of iron in cardiovascular disease (CVD) have been intensively studied for decades. Convincing data demonstrated a detrimental effect of iron deficiency in patients with heart failure and pulmonary arterial hypertension, but it remains unclear for the pathological roles of iron in other cardiovascular diseases. Meanwhile, ferroptosis is an iron-dependent cell death that is distinct from apoptosis, necroptosis, and other types of cell death. Ferroptosis has been reported in several CVDs, namely, cardiomyopathy, atherosclerotic cardiovascular disease, and myocardial ischemia/reperfusion injury. Iron chelation therapy seems to be an available strategy to ameliorate iron overload-related disorders. It is still a challenge to accurately clarify the pathological roles of iron in CVD and search for effective medical intervention. In this review, we aim to summarize the pathological roles of iron in CVD, and especially highlight the potential mechanism of ferroptosis in these diseases.

Biomarkers in the clinical management of patients with atrial fibrillation and heart failure

Atrial fibrillation (AF) and heart failure (HF) are two cardiovascular diseases with an increasing prevalence worldwide. These conditions share common pathophysiologiesand frequently co-exit. In fact, the occurrence of either condition can 'cause' the development of the other, creating a new patient group that demands different management strategies to that if they occur in isolation. Regardless of the temproral association of the two conditions, their presence is linked with adverse cardiovascular outcomes, increased rate of hospitalizations, and increased economic burden on healthcare systems. The use of low-cost, easily accessible and applicable biomarkers may hasten the correct diagnosis and the effective treatment of AF and HF. Both AF and HF effect multiple physiological pathways and thus a great number of biomarkers can be measured that potentially give the clinician important diagnostic and prognostic information. These will then guide patient centred therapeutic management. The current biomarkers that offer potential for guiding therapy, focus on the physiological pathways of miRNA, myocardial stretch and injury, oxidative stress, inflammation, fibrosis, coagulation and renal impairment. Each of these has different utility in current clinincal practice.

Contemporary approach to understand and manage COVID-19-related arrhythmia

Arrhythmia, one of the most common complications of COVID-19, was reported in nearly one-third of diagnosed COVID-19 patients, with higher prevalence rate among ICU admitted patients. The underlying etiology for arrhythmia in these cases are mostly multifactorial as those patients may suffer from one or more of the following predisposing mechanisms; catecholamine surge, hypoxia, myocarditis, cytokine storm, QTc prolongation, electrolyte disturbance, and pro-arrhythmic drugs usage. Obviously, the risk for arrhythmia and the associated lethal outcome would rise dramatically among patients with preexisting cardiac disease such as myocardial ischemia, heart failure, cardiomyopathy, and hereditary arrhythmias. Considering all of these variables, the management strategy of COVID-19 patients should expand from managing a viral infection and related host immune response to include the prevention of predictable causes for arrhythmia. This may necessitate the need to investigate the role of some drugs that modulate the pathway of arrhythmia generation. Of these drugs, we discuss the potential role of adrenergic antagonists, trimetazidine, ranolazine, and the debatable angiotensin converting enzyme inhibitors drugs. We also recommend monitoring the level of: unbound free fatty acids, serum electrolytes, troponin, and QTc (even in the absence of apparent pro-arrhythmic drug use) as these may be the only indicators for patients at risk for arrhythmic complications.

Increased Ferritin Concentration and Risk of Atrial Fibrillation and Heart Failure in Men and Women: Three Studies of the Danish General Population Including 35799 Individuals

BACKGROUND

Moderately increased plasma ferritin, as a biomarker of iron overload, has been associated with higher rates of cardiovascular death and heart failure. However, the association of moderately increased plasma ferritin with risk of atrial fibrillation in the general population is unknown.

METHODS

We examined the association of plasma ferritin concentrations with risk of atrial fibrillation and heart failure in metaanalyses of 35799 men and women from 3 studies of the Danish general population: the Copenhagen City Heart Study, the Danish General Suburban Population Study, and the Copenhagen General Population Study.

RESULTS

Multivariable adjusted fixed effects odds ratios for atrial fibrillation were 1.23 (95% CI, 1.05-1.44; P = 0.005) in men for ferritin concentration ≥300 μg/L vs <300 μg/L, 1.13 (95% CI, 0.93-1.38; P = 0.22) in women for ≥200 μg/L vs <200 μg/L, and 1.19 (95% CI, 1.06-1.35; P = 0.005) in both sexes combined (P _{sex interaction} = 0.52). Corresponding fixed effects odds ratios for heart failure were 1.16 (95% CI, 0.98-1.37; P = 0.08) in men, 0.86 (95% CI, 0.67-1.10; P = 0.23) in women, and 1.05 (95% CI, 0.91-1.21; P = 0.45) in both sexes combined (P _{sex interaction} = 0.05). Multivariable adjusted fixed effects odds ratio for atrial fibrillation per step increase in ferritin concentrations was 1.13 (95% CI, 1.06-1.21; P _trend = 0.0005) in both sexes combined (P _{sex interaction} = 0.59); the corresponding value for heart failure was 1.03 (95% CI, 0.95-1.11; P _trend = 0.47) (P _{sex interaction} = 0.08). In sensitivity analyses, there was no evidence of U-shaped relationships between plasma ferritin concentrations and risk of atrial fibrillation or heart failure in men or women.

CONCLUSIONS

Increased ferritin concentration is associated with increased risk of atrial fibrillation in the general population.

Cardiac repolarization and depolarization in people with Type 1 diabetes with normal ejection fraction and without known heart disease: a case-control study

AIMS

To investigate depolarization and repolarization durations in people with Type 1 diabetes, including the relationship to age.

METHODS

855 persons with Type 1 diabetes without known heart disease were included and matched with 1710 participants from a general population study. Clinical examinations, questionnaires and biochemistry were assessed. A 10-second 12-lead ECG was performed and analysed digitally.

RESULTS

QT_c was longer in people with Type 1 diabetes compared to controls (414±16 vs. 411±19 ms, P <0.001), and particularly so in young people with Type 1 diabetes. The fully adjusted increase was 13.8 ms (95% confidence interval (CI): 8.6-19.0 ms, P <0.001) at age 20 years and 3.4 ms (CI: 1.5-5.3 ms, P<0.001) at age 40 years. The rate-corrected QRS_c was increased in people with Type 1 diabetes (97±11 vs. 95±11 ms, P <0.001) and was age-independent (P =0.5). JT_c was increased in the young people with Type 1 diabetes (10.7 ms (CI: 5.4-16.0 ms, P <0.001) at age 20 years), but not in older people with Type 1 diabetes (interaction age-diabetes, P <0.01).

CONCLUSIONS

For people with Type 1 diabetes, cardiac depolarization is increased at all ages, whereas repolarization is increased only relatively in young people with Type 1 diabetes. Hence, young people with Type 1 diabetes may be more prone to ventricular arrhythmias. The findings contribute to the understanding of sudden cardiac death in young people with Type 1 diabetes.