Twenty-four hour Holter ECG in normocalcemic and hypercalcemic patients with hyperparathyroidism.

PURPOSE: To investigate the occurrence of arrhythmias in patients with normocalcemic (NC) primary hyperparathyroidism (PHPT) compared to both hypercalcemic PHPT patients and control subjects by means of 24-h Holter ECG. METHODS: Thirteen NCPHPT postmenopausal patients were enrolled and age-matched with 13 hypercalcemic PHPT patients and 13 controls. Every subject underwent basal ECG, 24-h Holter ECG and mineral metabolism biochemical evaluation. RESULTS: PHPT patients had higher mean serum calcium levels compared to both NCPHPT and controls; there was no difference in mean serum calcium levels between NCPHPT and controls. Both NCPHPT and PHPT patients had significantly higher mean PTH levels compared with controls. There were no differences in ECG parameters between the three groups, except for QTc interval. PHPT patients had normal QTc interval values, but significantly shorter mean values compared with those of controls and NCPHPT patients. During 24-h Holter ECG recording, 100% of PHPT patients had supraventricular premature beats (SVPBs), compared to 46% of NCPHPT (p = 0.005) and to 53% of controls (p = 0.01). PHPT patients experienced ventricular premature beats (VPBs) (69.2%) vs 15% of NCPHPT patients (p = 0.01) and 23% of controls (p = 0.04). There was no difference between NCPHPT and controls subjects concerning occurrence of both VPBs and SVPBs. CONCLUSIONS: NCPHPT patients did not experience an increased occurrence of arrhythmias compared to controls, while PHPT patients showed an increased occurrence compared to both controls and NCPHPT. Our findings are most probably related to the short QTc interval caused by hypercalcemia observed in PHPT patients, but not in NCPHPT.

IL-18 mediates sickle cell cardiomyopathy and ventricular arrhythmias.

Previous reports indicate that IL18 is a novel candidate gene for diastolic dysfunction in sickle cell disease (SCD)-related cardiomyopathy. We hypothesize that interleukin-18 (IL-18) mediates the development of cardiomyopathy and ventricular tachycardia (VT) in SCD. Compared with control mice, a humanized mouse model of SCD exhibited increased cardiac fibrosis, prolonged duration of action potential, higher VT inducibility in vivo, higher cardiac NF-κB phosphorylation, and higher circulating IL-18 levels, as well as reduced voltage-gated potassium channel expression, which translates to reduced transient outward potassium current (Ito) in isolated cardiomyocytes. Administering IL-18 to isolated mouse hearts resulted in VT originating from the right ventricle and further reduced Ito in SCD mouse cardiomyocytes. Sustained IL-18 inhibition via IL-18-binding protein resulted in decreased cardiac fibrosis and NF-κB phosphorylation, improved diastolic function, normalized electrical remodeling, and attenuated IL-18-mediated VT in SCD mice. Patients with SCD and either myocardial fibrosis or increased QTc displayed greater IL18 gene expression in peripheral blood mononuclear cells (PBMCs), and QTc was strongly correlated with plasma IL-18 levels. PBMC-derived IL18 gene expression was increased in patients who did not survive compared with those who did. IL-18 is a mediator of sickle cell cardiomyopathy and VT in mice and a novel therapeutic target in patients at risk for sudden death.

Acute Cardiovascular Manifestations in 286 Children With Multisystem Inflammatory Syndrome Associated With COVID-19 Infection in Europe.

BACKGROUND: The aim of the study was to document cardiovascular clinical findings, cardiac imaging, and laboratory markers in children presenting with the novel multisystem inflammatory syndrome associated with coronavirus disease 2019 (COVID-19) infection. METHODS: This real-time internet-based survey has been endorsed by the Association for European Paediatric and Congenital Cardiologists Working Groups for Cardiac Imaging and Cardiovascular Intensive Care. Children 0 to 18 years of age admitted to a hospital between February 1 and June 6, 2020, with a diagnosis of an inflammatory syndrome and acute cardiovascular complications were included. RESULTS: A total of 286 children from 55 centers in 17 European countries were included. The median age was 8.4 years (interquartile range, 3.8-12.4 years) and 67% were boys. The most common cardiovascular complications were shock, cardiac arrhythmias, pericardial effusion, and coronary artery dilatation. Reduced left ventricular ejection fraction was present in over half of the patients, and a vast majority of children had raised cardiac troponin when checked. The biochemical markers of inflammation were raised in most patients on admission: elevated C-reactive protein, serum ferritin, procalcitonin, N-terminal pro B-type natriuretic peptide, interleukin-6 level, and D-dimers. There was a statistically significant correlation between degree of elevation in cardiac and biochemical parameters and the need for intensive care support (P<0.05). Polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 was positive in 33.6%, whereas immunoglobulin M and immunoglobulin G antibodies were positive in 15.7% cases and immunoglobulin G in 43.6% cases, respectively, when checked. One child in the study cohort died. CONCLUSIONS: Cardiac involvement is common in children with multisystem inflammatory syndrome associated with the Covid-19 pandemic. The majority of children have significantly raised levels of N-terminal pro B-type natriuretic peptide, ferritin, D-dimers, and cardiac troponin in addition to high C-reactive protein and procalcitonin levels. In comparison with adults with COVID-19, mortality in children with multisystem inflammatory syndrome associated with COVID-19 is uncommon despite multisystem involvement, very elevated inflammatory markers, and the need for intensive care support.

Plasma potassium concentration and cardiac repolarisation markers, Tpeak-Tend and Tpeak-Tend/QT, during and after exercise in healthy participants and in end-stage renal disease.

PURPOSE: The cardiac T-wave peak-to-end interval (Tpe) is thought to reflect dispersion in ventricular repolarisation, with abnormalities in Tpe associated with increased risk of arrhythmia. Extracellular K+ modulates cardiac repolarisation, and since arterial plasma K+ concentration ([K+]) rapidly increases during and declines following exercise, we investigated the relationship between [K+] and Tpe with exercise. METHODS: Serial ECGs (Tpe, Tpe/QT ratio) and [K+] were obtained from 8 healthy, normokalaemic volunteers and 22 patients with end-stage renal disease (ESRD), at rest, during, and after exhaustive exercise. RESULTS: Post-exercise [K+] nadir was 3.1 ± 0.1, 5.0 ± 0.2 and 4.0 ± 0.1 mmol.L-1 (mean ± SEM) for healthy participants and ESRD patients before and after haemodialysis, respectively. In healthy participants, compared to pre-exercise, recovery-induced low [K+] was associated with a prolongation of Tpe (110 ± 8 vs. 87 ± 5 ms, respectively, p = 0.03) and an increase in Tpe/QT ratio (0.28 ± 0.01 vs. 0.23 ± 0.01, respectively, p = 0.01). Analyses of serial data revealed [K+] as a predictor of Tpe in healthy participants (ß = -0.54 ±0.05, p < 0.0001), in ESRD patients (ß = -0.75 ± 0.06, p < 0.0001) and for all data pooled (ß = -0.61 ± 0.04, p < 0.0001). The [K+] was also a predictor of Tpe/QT ratio in healthy participants and ESRD patients. CONCLUSIONS: Tpe and Tpe/QT ratio are predicted by [K+] during exercise. Low [K+] during recovery from exercise was associated with increased Tpe and Tpe/QT, indicating accentuated dispersion of ventricular repolarisation. The findings suggest that variations in [K+] with physical exertion may unmask electrophysiological vulnerabilities to arrhythmia.

Autoantibody Signature in Cardiac Arrest.

BACKGROUND: Cardiac arrest is a tragic event that causes 1 death roughly every 90 seconds worldwide. Survivors generally undergo a workup to identify the cause of arrest. However, 5% to 10% of cardiac arrests remain unexplained. Because cardiac arrhythmias underlie most cardiac arrests and increasing evidence strongly supports the involvement of autoantibodies in arrhythmogenesis, a large-panel autoantibody screening was performed in patients with cardiac arrest. METHODS: This is an observational, cross-sectional study of patients from the Montreal Heart Institute hospital cohort, a single-center registry of participants. A peptide microarray was designed to screen for immunoglobulin G targeting epitopes from all known cardiac ion channels with extracellular domains. Plasma samples from 23 patients with unexplained cardiac arrest were compared with those from 22 patients with cardiac arrest cases of ischemic origin and a group of 29 age-, sex-, and body mass index-matched healthy subjects. The false discovery rate, least absolute shrinkage and selection operator logistic regression, and random forest methods were carried out jointly to find significant differential immunoglobulin G responses. RESULTS: The autoantibody against the pore domain of the L-type voltage-gated calcium channel was consistently identified as a biomarker of idiopathic cardiac arrest (P=0.002; false discovery rate, 0.007; classification accuracies ≥0.83). Functional studies on human induced pluripotent stem cell-derived cardiomyocytes demonstrated that the anti-L-type voltage-gated calcium channel immunoglobulin G purified from patients with idiopathic cardiac arrest is proarrhythmogenic by reducing the action potential duration through calcium channel inhibition. CONCLUSIONS: The present report addresses the concept of autoimmunity and cardiac arrest. Hitherto unknown autoantibodies targeting extracellular sequences of cardiac ion channels were detected. Moreover, the study identified an autoantibody signature specific to patients with cardiac arrest.

Association of lower vitamin D levels with inflammation and leucocytes parameters in patients with and without diabetes mellitus undergoing coronary angiography.

BACKGROUND: Diabetes mellitus has been associated with a chronic low-grade inflammation and a higher risk of cardiovascular and infectious disease, that could be prevented by the effects of vitamin D. We aimed at evaluating the impact of vitamin D levels on the biomarkers of acute-phase response, inflammation and glucose metabolism in a large cohort of diabetic patients with cardiovascular disease. MATERIALS AND METHODS: Consecutive patients undergoing coronary angiography were included. Diabetes mellitus was defined as previous diagnosis, specific treatment administration (oral drug or insulin), fasting glycaemia >6.99 mmol/L or HbA1c >48 mmol/L. Glucose parameters, white blood cells, Neutrophil-to-Lymphocyte Ratio (NLR), Monocyte-to-Lymphocyte Ratio (MLR), C-reactive protein (CRP) and vitamin D were measured at admission. Vitamin D levels were measured by chemiluminescence immunoassay kit LIAISON® Vitamin D assay (Diasorin Inc). RESULTS: We included 1472 diabetic patients and 2499 non-diabetic patients that were divided according to vitamin D tertiles. Among diabetic patients, lower levels of vitamin D were associated with female gender (P = .02), obesity (P = .004), active smoking and acute presentation (P < .001) and with a more atherogenic metabolic profile. The levels of white blood cells, leucocytes subfamilies, and inflammatory parameters significantly correlated with vitamin D levels in both patients with and without diabetes (diabetic: P = .012 for WBC, P = .004 for NLR and P < .001 for MLR and C-reactive protein, non-diabetic: P < .001 for WBC; NLR, MLR and C-reactive protein, respectively). Among diabetic patients, results were confirmed at multivariate analysis with no significant interaction according to glycaemic control. CONCLUSION: The present study demonstrates that, among patients with cardiovascular disease, vitamin D deficiency is associated with metabolic dysregulation and with an elevation of cellular and humoural inflammatory parameters, especially among diabetics, although not being dependent from glycaemic control.

Significant abnormal glycemic variability increased the risk for arrhythmias in elderly type 2 diabetic patients.

BACKGROUND: Little is known about whether the influence of glycemic variability on arrhythmia is related to age in type 2 diabetes mellitus (T2DM). Therefore, we aimed to compare the association between glycemic variability and arrhythmia in middle-aged and elderly T2DM patients. METHODS: A total of 107 patients were divided into two groups: elderly diabetes mellitus group (EDM, n = 73) and middle-aged diabetes mellitus group (MDM, n = 34). The main clinical data, continuous glucose monitoring (CGM) and dynamic ECG reports were collected. The parameters including standard deviation of blood glucose (SDBG), largest amplitude of glycemic excursions (LAGE), mean amplitude of glycemic excursions (MAGE), absolute means of daily differences (MODD), time in range (TIR), time below range (TBR), time above range (TAR), coefficient of variation (CV) were tested for glycemic variability evaluation. RESULTS: In terms of blood glucose fluctuations, MAGE (5.77 ± 2.16 mmol/L vs 4.63 ± 1.89 mmol/L, P = 0.026), SDBG (2.39 ± 1.00 mmol/L vs 2.00 ± 0.82 mmol/L, P = 0.048), LAGE (9.53 ± 3.37 mmol/L vs 7.84 ± 2.64 mmol/L, P = 0.011) was significantly higher in EDM group than those of MDM group. The incidences of atrial premature beat, couplets of atrial premature beat, atrial tachycardia and ventricular premature beat were significantly higher in EDM group compared with the MDM group (all P < 0.05). Among patients with hypoglycemia events, the incidences of atrial premature beat, couplets of atrial premature beat, atrial tachycardia and ventricular premature beat (all P < 0.05) were significantly higher in the EDM group than those in the MDM group. In EDM group, TIR was negatively correlated with atrial tachycardia in the MAGE1 layer and with atrial tachycardia and ventricular premature beat in the MAGE2 layer, TBR was significantly positively correlated with atrial tachycardia in the MAGE2 layer (all P < 0.05). In MDM group, TAR was positively correlated with ventricular premature beat and atrial tachycardia in the MAGE2 layer (all P < 0.05). CONCLUSIONS: The study demonstrated the elderly patients had greater glycemic variability and were more prone to arrhythmias. Therefore, active control of blood glucose fluctuation in elderly patients will help to reduce the risk of severe arrhythmia.

Association of Lipoprotein (a) variants with risk of cardiovascular disease: a Mendelian randomization study.

BACKGROUND: There is a well-documented empirical relationship between lipoprotein (a) [Lp(a)] and cardiovascular disease (CVD); however, causal evidence, especially from the Chinese population, is lacking. Therefore, this study aims to estimate the causal association between variants in genes affecting Lp(a) concentrations and CVD in people of Han Chinese ethnicity. METHODS: Two-sample Mendelian randomization analysis was used to assess the causal effect of Lp(a) concentrations on the risk of CVD. Summary statistics for Lp(a) variants were obtained from 1256 individuals in the Cohort Study on Chronic Disease of Communities Natural Population in Beijing, Tianjin and Hebei. Data on associations between single-nucleotide polymorphisms (SNPs) and CVD were obtained from recently published genome-wide association studies. RESULTS: Thirteen SNPs associated with Lp(a) levels in the Han Chinese population were used as instrumental variables. Genetically elevated Lp(a) was inversely associated with the risk of atrial fibrillation [odds ratio (OR), 0.94; 95% confidence interval (95%CI), 0.901-0.987; P = 0.012)], the risk of arrhythmia (OR, 0.96; 95%CI, 0.941-0.990; P = 0.005), the left ventricular mass index (OR, 0.97; 95%CI, 0.949-1.000; P = 0.048), and the left ventricular internal dimension in diastole (OR, 0.97; 95%CI, 0.950-0.997; P = 0.028) according to the inverse-variance weighted method. No significant association was observed for congestive heart failure (OR, 0.99; 95% CI, 0.950-1.038; P = 0.766), ischemic stroke (OR, 1.01; 95%CI, 0.981-1.046; P = 0.422), and left ventricular internal dimension in systole (OR, 0.98; 95%CI, 0.960-1.009; P = 0.214). CONCLUSIONS: This study provided evidence that genetically elevated Lp(a) was inversely associated with atrial fibrillation, arrhythmia, the left ventricular mass index and the left ventricular internal dimension in diastole, but not with congestive heart failure, ischemic stroke, and the left ventricular internal dimension in systole in the Han Chinese population. Further research is needed to identify the mechanism underlying these results and determine whether genetically elevated Lp(a) increases the risk of coronary heart disease or other CVD subtypes.

PACAP-38 in Acute ST-Segment Elevation Myocardial Infarction in Humans and Pigs: A Translational Study.

Acute myocardial infarction (MI) is one of the most common causes of death worldwide. Pituitary adenylate cyclase activating polypeptide (PACAP) is a cardioprotective neuropeptide expressing its receptors in the cardiovascular system. The aim of our study was to examine tissue PACAP-38 in a translational porcine MI model and plasma PACAP-38 levels in patients with ST-segment elevation myocardial infarction (STEMI). Significantly lower PACAP-38 levels were detected in the non-ischemic region of the left ventricle (LV) in MI heart compared to the ischemic region of MI-LV and also to the Sham-operated LV in porcine MI model. In STEMI patients, plasma PACAP-38 level was significantly higher before percutaneous coronary intervention (PCI) compared to controls, and decreased after PCI. Significant negative correlation was found between plasma PACAP-38 and troponin levels. Furthermore, a significant effect was revealed between plasma PACAP-38, hypertension and HbA1c levels. This was the first study showing significant changes in cardiac tissue PACAP levels in a porcine MI model and plasma PACAP levels in STEMI patients. These results suggest that PACAP, due to its cardioprotective effects, may play a regulatory role in MI and could be a potential biomarker or drug target in MI.

Effect of metoprolol tartrate tablets and recombinant human B-type natriuretic peptide on the sudden cardiac death and malignant arrhythmias in patients with acute myocardial infarction and heart failure.

To explore the effect of metoprolol tartrate tablets and recombinant human natriuretic peptide B (NPPB) on sudden cardiac death and malignant arrhythmias in patients with acute myocardial infarction and patients with heart failure (AMI-HF). A total of 105 AMI-HF patients treatedfrom January 2020 and June 2021 were enrolled and divided into Group I (n=53) and Group II (n=52). Both groups received conventional treatment, and Group II was additionally treated with metoprolol tartrate tablets and NPPB. The clinical observation indicators of the two groups of patients were compared. Group II had better left ventricular end diastolic diameter (LVEDd), left ventricular end systolic diameter (LVESD) and left ventricular ejection fraction (LVEF) (p<0.05). The standard deviation of NN (R-R) interval (SDNN), mean NN (R-R), root mean square of continuous difference (RMSSD) and the percentage of difference between adjacent RR intervals >50ms (pNN50) increased after treatment, with more increase in the Group II (p<0.05). Group II obtained significantly lower levels of B type natriuretic peptide (BNP),N terminal pro B type natriuretic peptide (NT-ProBNP), interleukin (IL)-6 and hs-CRP in contrast to Group I (p<0.05). Markedly higher total response rates were observed in Group II (p<0.05). The combination of metoprolol tartrate tablets and NPPB is effective in treating AMI-HF.

Amiodarone disrupts cholesterol biosynthesis pathway and causes accumulation of circulating desmosterol by inhibiting 24-dehydrocholesterol reductase.

BACKGROUND: We have earlier reported that amiodarone, a potent and commonly used antiarrhythmic drug increases serum desmosterol, the last precursor of cholesterol, in 20 cardiac patients by an unknown mechanism. OBJECTIVE: Here, we extended our study to a large number of cardiac patients of heterogeneous diagnoses, evaluated the effects of combining amiodarone and statins (inhibitors of cholesterol synthesis at the rate-limiting step of hydroxy-methyl-glutaryl CoA reductase) on desmosterol levels and investigated the mechanism(s) by which amiodarone interferes with the metabolism of desmosterol using in vitro studies. METHODS AND RESULTS: We report in a clinical case-control setting of 236 cardiac patients (126 with and 110 without amiodarone treatment) that amiodarone medication is accompanied by a robust increase in serum desmosterol levels independently of gender, age, body mass index, cardiac and other diseases, and the use of statins. Lipid analyses in patient samples taken before and after initiation of amiodarone therapy showed a systematic increase of desmosterol upon drug administration, strongly arguing for a direct causal link between amiodarone and desmosterol accumulation. Mechanistically, we found that amiodarone resulted in desmosterol accumulation in cultured human cells and that the compound directly inhibited the 24-dehydrocholesterol reductase (DHCR24) enzyme activity. CONCLUSION: These novel findings demonstrate that amiodarone blocks the cholesterol synthesis pathway by inhibiting DHCR24, causing a robust accumulation of cellular desmosterol in cells and in the sera of amiodarone-treated patients. It is conceivable that the antiarrhythmic potential and side effects of amiodarone may in part result from inhibition of the cholesterol synthesis pathway.

Macrophage-mediated regulation of catecholamines in sympathetic neural remodeling after myocardial infarction.

Sympathetic neural remodeling, which involves the inflammatory response, plays an important role in ventricular arrhythmias (VAs) after myocardial infarction (MI). Adrenergic receptors on macrophages potentially modulate the inflammatory response. We hypothesized that the increased level of catecholamines activates macrophages and regulates sympathetic neural remodeling after MI. We treated MI mice with either clodronate or metoprolol for 5 days following coronary artery ligation. Mice without treatment after MI and sham-operation mice served as the positive control and negative control, respectively. The norepinephrine levels in plasma and the peri-infarct myocardium increased by almost two-fold in the MI mice compared with the sham-operation mice. Both in vivo and ex vivo electrophysiology examinations showed that the vulnerability to VAs induced by MI was alleviated by macrophage depletion with clodronate and ß1-adrenergic blockade with metoprolol, which was in line with circulating and peri-infarct norepinephrine levels, sympathetic reinnervation, and the expression of nerve growth factor (NGF) 7 days after surgery. To further verify the interaction between catecholamines and macrophages, we preconditioned lipopolysaccharide-stimulated RAW 264.7 cells using epinephrine or epinephrine with selective adrenergic antagonists. The expression and release of inflammatory factors including NGF were enhanced by epinephrine. This effect was inhibited by metoprolol but not by other subtype antagonists. Our data suggested that the increased level of catecholamines, traditionally known as positive inotropes secreted from sympathetic nerve endings, might regulate cardiac sympathetic neural remodeling through ß1-adrenergic receptors on macrophages, subsequently inducing VAs after MI.

Hyperglycemia regulates cardiac K+ channels via O-GlcNAc-CaMKII and NOX2-ROS-PKC pathways.

Chronic hyperglycemia and diabetes lead to impaired cardiac repolarization, K+ channel remodeling and increased arrhythmia risk. However, the exact signaling mechanism by which diabetic hyperglycemia regulates cardiac K+ channels remains elusive. Here, we show that acute hyperglycemia increases inward rectifier K+ current (IK1), but reduces the amplitude and inactivation recovery time of the transient outward K+ current (Ito) in mouse, rat, and rabbit myocytes. These changes were all critically dependent on intracellular O-GlcNAcylation. Additionally, IK1 amplitude and Ito recovery effects (but not Ito amplitude) were prevented by the Ca2+/calmodulin-dependent kinase II (CaMKII) inhibitor autocamtide-2-related inhibitory peptide, CaMKIIδ-knockout, and O-GlcNAc-resistant CaMKIIδ-S280A knock-in. Ito reduction was prevented by inhibition of protein kinase C (PKC) and NADPH oxidase 2 (NOX2)-derived reactive oxygen species (ROS). In mouse models of chronic diabetes (streptozotocin, db/db, and high-fat diet), heart failure, and CaMKIIδ overexpression, both Ito and IK1 were reduced in line with the downregulated K+ channel expression. However, IK1 downregulation in diabetes was markedly attenuated in CaMKIIδ-S280A. We conclude that acute hyperglycemia enhances IK1 and Ito recovery via CaMKIIδ-S280 O-GlcNAcylation, but reduces Ito amplitude via a NOX2-ROS-PKC pathway. Moreover, chronic hyperglycemia during diabetes and CaMKII activation downregulate K+ channel expression and function, which may further increase arrhythmia susceptibility.

Death, discharge and arrhythmias among patients with COVID-19 and cardiac injury.

BACKGROUND: Cardiac injury is common in severe coronavirus disease 2019 (COVID-19) and is associated with poor outcomes. We aimed to study predictors of in-hospital death, characteristics of arrhythmias and the effects of QT-prolonging therapy in patients with cardiac injury. METHODS: We conducted a retrospective cohort study involving patients with severe COVID-19 who were admitted to Tongji Hospital in Wuhan, China, between Jan. 29 and Mar. 8, 2020. Among patients who had cardiac injury, which we defined as an elevated level of cardiac troponin I (cTnI), we identified demographic and clinical characteristics associated with mortality and need for invasive ventilation. RESULTS: Among 1284 patients with severe COVID-19, 1159 had a cTnI level measured on admission to hospital, of whom 170 (14.7%) had results that showed cardiac injury. We found that mortality was markedly higher in patients with cardiac injury (71.2% v. 6.6%, p < 0.001). We determined that initial cTnI (per 10-fold increase, hazard ratio [HR] 1.32, 95% confidence interval [CI] 1.06-1.66) and peak cTnI level during illness (per 10-fold increase, HR 1.70, 95% CI 1.38-2.10) were associated with poor survival. Peak cTnI was also associated with the need for invasive ventilation (odds ratio 3.02, 95% CI 1.92-4.98). We found arrhythmias in 44 of the 170 patients with cardiac injury (25.9%), including 6 patients with ventricular tachycardia or fibrillation, all of whom died. We determined that patients who received QT-prolonging drugs had longer QTc intervals than those who did not receive them (difference in medians, 45 ms, p = 0.01), but such treatment was not independently associated with mortality (HR 1.04, 95% CI 0.69-1.57). INTERPRETATION: We found that in patients with COVID-19 and cardiac injury, initial and peak cTnI levels were associated with poor survival, and peak cTnI was a predictor of need for invasive ventilation. Patients with COVID-19 warrant assessment for cardiac injury and monitoring, especially if therapy that can prolong repolarization is started. TRIAL REGISTRATION: Chinese Clinical Trial Registry, No. ChiCTR2000031301.

Inhalation of printer-emitted particles impairs cardiac conduction, hemodynamics, and autonomic regulation and induces arrhythmia and electrical remodeling in rats.

BACKGROUND: Using engineered nanomaterial-based toners, laser printers generate aerosols with alarming levels of nanoparticles that bear high bioactivity and potential health risks. Yet, the cardiac impacts of printer-emitted particles (PEPs) are unknown. Inhalation of particulate matter (PM) promotes cardiovascular morbidity and mortality, and ultra-fine particulates (< 0.1 µm aerodynamic diameter) may bear toxicity unique from larger particles. Toxicological studies suggest that PM impairs left ventricular (LV) performance; however, such investigations have heretofore required animal restraint, anesthesia, or ex vivo preparations that can confound physiologic endpoints and/or prohibit LV mechanical assessments during exposure. To assess the acute and chronic effects of PEPs on cardiac physiology, male Sprague Dawley rats were exposed to PEPs (21 days, 5 h/day) while monitoring LV pressure (LVP) and electrocardiogram (ECG) via conscious telemetry, analyzing LVP and heart rate variability (HRV) in four-day increments from exposure days 1 to 21, as well as ECG and baroreflex sensitivity. At 2, 35, and 70 days after PEPs exposure ceased, rats received stress tests. RESULTS: On day 21 of exposure, PEPs significantly (P < 0.05 vs. Air) increased LV end systolic pressure (LVESP, + 18 mmHg) and rate-pressure-product (+ 19%), and decreased HRV indicating sympathetic dominance (root means squared of successive differences [RMSSD], - 21%). Overall, PEPs decreased LV ejection time (- 9%), relaxation time (- 3%), tau (- 5%), RMSSD (- 21%), and P-wave duration (- 9%). PEPs increased QTc interval (+ 5%) and low:high frequency HRV (+ 24%; all P < 0.05 vs. Air), while tending to decrease baroreflex sensitivity and contractility index (- 15% and - 3%, P < 0.10 vs. Air). Relative to Air, at both 2 and 35 days after PEPs, ventricular arrhythmias increased, and at 70 days post-exposure LVESP increased. PEPs impaired ventricular repolarization at 2 and 35 days post-exposure, but only during stress tests. At 72 days post-exposure, PEPs increased urinary dopamine 5-fold and protein expression of ventricular repolarizing channels, Kv1.5, Kv4.2, and Kv7.1, by 50%. CONCLUSIONS: Our findings suggest exposure to PEPs increases cardiovascular risk by augmenting sympathetic influence, impairing ventricular performance and repolarization, and inducing hypertension and arrhythmia. PEPs may present significant health risks through adverse cardiovascular effects, especially in occupational settings, among susceptible individuals, and with long-term exposure.

Racial and Ethnic Differences in Mortality Associated with Serum Potassium in Incident Peritoneal Dialysis Patients.

BACKGROUND: Abnormalities in serum potassium are risk factors for sudden cardiac death and arrhythmias among dialysis patients. Although a previous study in hemodialysis patients has shown that race/ethnicity may impact the relationship between serum potassium and mortality, the relationship remains unclear among peritoneal dialysis (PD) patients where the dynamics of serum potassium is more stable. METHODS: Among 17,664 patients who started PD between January 1, 2007 and December 31, 2011 in a large US dialysis organization, we evaluated the association of serum potassium levels with all-cause and arrhythmia-related deaths across race/ethnicity using time-dependent Cox models with adjustments for demographics. We also used restricted cubic spline functions for serum potassium levels to explore non-linear associations. RESULTS: Baseline serum potassium levels were the highest among Hispanics (4.2 ± 0.7 mEq/L) and lowest among non-Hispanic blacks (4.0 ± 0.7 mEq/L). Among 2,949 deaths during the follow-up of median 2.2 (interquartile ranges 1.3-3.2) years, 683 (23%) were arrhythmia-related deaths. Overall, both hyperkalemia and hypokalemia (i.e., serum potassium levels >5.0 and <3.5 mEq/L, respectively) were associated with higher all-cause and arrhythmia-related mortality. In a stratified analysis according to race/ethnicity, the association of hypokalemia with all-cause and arrhythmia-related mortality was consistent with an attenuation for arrhythmia-related mortality in non-Hispanic blacks. Hyperkalemia was associated with all-cause and arrhythmia-related mortality in non-Hispanic whites and non-Hispanic blacks, but no association was observed in Hispanics. CONCLUSION: Among incident PD patients, hypokalemia was consistently associated with all-cause and arrhythmia-related deaths irrespective of race/ethnicity. However, while hyperkalemia was associated with both death outcomes in non-Hispanic blacks and whites, it was not associated with either death outcome in Hispanic patients. Further studies are needed to demonstrate whether different strategies should be followed for the management of serum potassium levels according to race/ethnicity.

Effect of Bicarbonate-Buffered Dialysate on Ventricular Arrhythmias in Hemodialysis Patients.

BACKGROUND: The etiology of sudden cardiac death in patients with end-stage renal disease (ESRD) on hemodialysis (HD) is largely unknown, though there is evidence to suggest that metabolic alkalosis induced by HD with a high-bicarbonate dialysate/prescription may play a role. METHODS: We investigated the effects of metabolic alkalosis induced by HD with an acetate-containing bicarbonate-buffered dialysate on frequency of ventricular arrhythmia in 47 patients with ESRD on chronic HD using 48-h Holter monitoring in 3 phases: intra-HD, post-HD day 1, and post-HD day 2. Serum levels of bicarbonate, calcium, and potassium along with hemodynamics were measured pre-HD, post-HD, 20-h post-HD, and 44-h post-HD. Correlations were performed to verify the association between bicarbonate prescription and change in serum bicarbonate levels post-HD and to determine if the HD-induced change in serum bicarbonate level (metabolic alkalosis) had any direct association with ambient ventricular arrhythmia (premature ventricular contractions per hour) or indirect associations with ambient ventricular arrhythmia by affecting electrolytes or hemodynamics that are known to increase the risk of ventricular arrhythmia. RESULTS: Mean pre-HD serum bicarbonate level was 21.3 mEq/L. Dialysate bicarbonate prescription (mean of 36.4 mEq/L) correlated with changes in serum bicarbonate levels immediately post-HD 26.7 mEq/L (r = 0.46, p < 0.01), 20-h post-HD 25.2 mEq/L (r = 0.38), and 44-h post-HD 23.2 mEq/L (r = 0.35, p = 0.01). No statistically significant correlations were found between the post-HD change in serum bicarbonate levels (metabolic alkalosis) with ambient ventricular arrhythmia, changes in serum calcium, potassium, or hemodynamics in any phase. CONCLUSIONS: High-bicarbonate dialysate prescription is associated with metabolic alkalosis following the HD procedure. A mild metabolic alkalosis induced by HD with an acetate-containing bicarbonate-buffered dialysate solution had no direct association with ambient ventricular arrhythmia on Holter monitoring and was not associated with changes in hemodynamics or changes in serum total calcium or potassium levels. This study helps to provide guidance for the safe use of high bicarbonate dialysate/prescription in patients with ESRD on HD.

Diagnostic Value of Different Noninvasive Criteria of Latent Myocarditis in Comparison with Myocardial Biopsy.

PURPOSE: The aim of this study was to quantify the value of various clinical, laboratory, and instrumental signs in the diagnosis of myocarditis in comparison with morphological studies of the myocardium. METHODS: In 100 patients (65 men, 44.7 ± 12.5 years old) with "idiopathic" arrhythmias (n = 20) and dilated cardiomyopathy (DCM; n = 80), we performed the following: 71 endomyocardial biopsies (EMB), 13 intraoperative biopsies, 5 studies of explanted hearts, and 11 autopsies with virus investigation (real-time PCR) of the blood and myocardium. Antiheart antibodies (AHA) were also measured as well as cardiac CT (n = 45), MRI (n = 25), and coronary angiography (n = 47). The comparison group included 50 patients (25 men, 53.7 ± 11.7 years old) with noninflammatory heart diseases who underwent open heart surgery. RESULTS: Active/borderline myocarditis was diagnosed in 76.0% of the study group and in 21.6% of patients in the comparison group (p < 0.001). The myocardial viral genome was observed more frequently in patients in the comparison group than in the study group (65.0 and 40.2%; p < 0.01). We evaluated the diagnostic value of noninvasive markers of myocarditis. The panel of AHA had the greatest importance in the identification of myocarditis: sensitivity was 81.5%, and the positive and negative predictive values were 75.0 and 60.5%. This defined the diagnostic value of noninvasive markers of myocarditis and established a diagnostic algorithm providing an individual assessment of the likelihood of myocarditis development. CONCLUSION: AHA have the greatest significance in the diagnosis of latent myocarditis in patients with "idiopathic" arrhythmias and DCM. The use of a complex of noninvasive criteria allows the probability of myocarditis to be estimated and the indications for EMB to be determined.

Predictors of cardiac arrhythmic events in non coronary artery disease patients.

Arrhythmic sudden cardiac death (SCD) represents a major worldwide public health problem accounting for 15-20% of deaths. Risk stratification to identify patients at risk of SCD is crucial in order to implement preventive measures in the general population. Several biomarkers have been tested exploring different pathophysiological mechanisms of cardiac conditions. Conflicting results have been described limiting so far their use in clinical practice. The use of new biomarkers such as microRNAs and sex hormones and the emerging role of genetic on risk prediction of SCD is a current research topic showing promising results.This review outlines the role of plasma biomarkers to predict ventricular arrhythmias and SCD in non coronary artery disease with a special focus on their relationship with the genetic biomarkers.

Plasma fatty acid-binding protein 4 (FABP4) level is associated with abnormal QTc interval in patients with stable angina and chronic kidney disease.

BACKGROUND: Fatty acid-binding protein 4 (FABP4) (also known as adipocyte FABP or adipocyte P2) is expressed in adipocytes, macrophages, and capillary endothelial cells. Previous studies have shown associations among plasma FABP4, insulin resistance, metabolic syndrome, diabetes mellitus, greater coronary plaque burden, coronary artery disease, heart failure, and mortality. However, little is known about the relationship between FABP4 level and prolonged QT interval. The aim of this study was to investigate whether plasma FABP4 level is associated with a prolonged QT interval by analyzing 12-lead electrocardiograms (ECGs) in patients with stable angina and chronic kidney disease (CKD). METHODS: This study included 397 consecutive patients with stable angina and CKD who were enrolled in a disease management program. Plasma FABP4 concentrations were measured using enzyme-linked immunosorbent assays. A 12-lead ECG recording was obtained from each patient. We assessed the relationships between FABP4 levels (both as a continuous variable and stratified by tertile) at admission and corrected QT (QTc) prolongation. RESULTS: Patients with an abnormal QTc interval had higher median plasma FABP4 levels than those with borderline and normal QTc intervals (15.9 ng/mL vs. 10.2 ng/mL vs. 8.5 ng/mL, respectively, P < 0.0001). Statistically significant associations were observed between plasma FABP4 levels and QTc interval (ß = 0.267, P < 0.0001). Using multivariate and trend analyses, a higher concentration of plasma FABP4 level was independently associated with QTc prolongation in patients with stable angina and CKD. CONCLUSION: In this study, plasma FABP4 levels were significantly higher in the patients with an abnormal QTc interval and were correlated with QTc prolongation. Further studies are required to elucidate whether plasma FABP4 plays a role in the pathogenesis of QTc prolongation.