Emerging Arrhythmic Risk of Autoimmune and Inflammatory Cardiac Channelopathies

Case report: A 56-year-old woman presenting with torsades de pointes and cardiac arrest associated with levosimendan administration and underlying congenital long QT syndrome type 1

Torsades de Pointes (TdP) is a malignant polymorphic ventricular tachycardia with heart rate corrected QT interval (QTc) prolongation, which may be attributed to congenital and acquired factors. Although various acquired factors for TdP have been summarized, levosimendan administration in complex postoperative settings is relatively uncommon. Timely identification of potential causes and appropriate management may improve the outcome. Herein, we describe the postoperative case of a 56-year-old female with initial normal QTc who accepted the administration of levosimendan for heart failure, suffered TdP, cardiac arrest, and possible Takotsubo cardiomyopathy, further genetically confirmed as long QT syndrome type 1 (LQT1). The patient was successfully treated with magnesium sulfate, atenolol, and implantable cardioverter defibrillator implantation. There should be a careful evaluation of the at-risk populations and close monitoring of the electrocardiograms, particularly the QT interval, to reduce the risk of near-fatal arrhythmias during the use of levosimendan.

Proteomics couples electrical remodelling to inflammation in a murine model of heart failure with sinus node dysfunction

AIMS

In patients with heart failure (HF), concomitant sinus node dysfunction (SND) is an important predictor of mortality, yet its molecular underpinnings are poorly understood. Using proteomics, this study aimed to dissect the protein and phosphorylation remodelling within the sinus node in an animal model of HF with concurrent SND.

METHODS AND RESULTS

We acquired deep sinus node proteomes and phosphoproteomes in mice with heart failure and SND and report extensive remodelling. Intersecting the measured (phospho)proteome changes with human genomics pharmacovigilance data, highlighted downregulated proteins involved in electrical activity such as the pacemaker ion channel, Hcn4. We confirmed the importance of ion channel downregulation for sinus node physiology using computer modelling. Guided by the proteomics data, we hypothesized that an inflammatory response may drive the electrophysiological remodeling underlying SND in heart failure. In support of this, experimentally induced inflammation downregulated Hcn4 and slowed pacemaking in the isolated sinus node. From the proteomics data we identified proinflammatory cytokine-like protein galectin-3 as a potential target to mitigate the effect. Indeed, in vivo suppression of galectin-3 in the animal model of heart failure prevented SND.

CONCLUSION

Collectively, we outline the protein and phosphorylation remodeling of SND in heart failure, we highlight a role for inflammation in electrophysiological remodelling of the sinus node, and we present galectin-3 signalling as a target to ameliorate SND in heart failure.

Effectiveness and safety of IL1 inhibition with anakinra in chronic refractory idiopathic myocarditis

AIM

The aim of this study was to evaluate the effectiveness and safety of the anti-IL-1 receptor anakinra in patients with chronic active myocarditis refractory to standard therapy.

METHODS AND RESULTS

In this retrospective, observational study, we enrolled 6 patients with chronically active myocarditis treated with anakinra on-top-of standard treatment. Response to treatment was evaluated at different time points [disease onset (T0), anakinra beginning (T1), three months from anakinra beginning (T2), last available follow-up (T3)], and was assessed by variations in New York Heart Association (NYHA) functional class, laboratory tests [C-reactive protein (CRP), a high-sensitivity cardiac troponin T (cTnT), and Nt-proBNP], left ventricular ejection fraction (LVEF), and cardiac magnetic resonance (CMR) edema or late gadolinium enhancement. The number of premature ventricular complexes (PVCs) at 24-h EKG-recordings was considered in patients with arrhythmic manifestations. No differences were found between T0 and T1 in terms of CRP, Nt-ProBNP, and LVEF. Before anakinra beginning, all patients were still symptomatic. At T2, all patients were symptom-free, in NYHA class I. A significant decrease in CRP (p = 0.03) and a significant improvement in LVEF (p = 0.03) were observed. Sustained arrhythmic manifestations were found in 4 out of 6 patients. In this subgroup, anakinra showed effectiveness in reducing the arrhythmic burden. At T3, the improvement in laboratory values and cardiac function persisted. The arrhythmic burden remained abated.

CONCLUSIONS

All patients had a rapid improvement in systemic inflammation, cardiac function, and arrhythmic burden with anti-IL1 therapy, indicating that anakinra may be an effective treatment in chronic active idiopathic myocarditis, refractory to standard treatment.

Elevated Interleukin-6 Levels Are Associated With an Increased Risk of QTc Interval Prolongation in a Large Cohort of US Veterans

BACKGROUND

Although accumulating data indicate that IL-6 (interleukin-6) can promote heart rate-corrected QT interval (QTc) prolongation via direct and indirect effects on cardiac electrophysiology, current evidence comes from basic investigations and small clinical studies only. Therefore, IL-6 is still largely ignored in the clinical management of long-QT syndrome and related arrhythmias. The aim of this study was to estimate the risk of QTc prolongation associated with elevated IL-6 levels in a large population of unselected subjects.

METHODS AND RESULTS

An observational study using the Veterans Affairs Informatics and Computing Infrastructure was performed. Participants were US veterans who had an ECG and were tested for IL-6. Descriptive statistics and univariate and multivariate regression analyses were performed to study the relationship between IL-6 and QTc prolongation risk. Study population comprised 1085 individuals, 306 showing normal (<5 pg/mL), 376 moderately high (5-25 pg/mL), and 403 high (>25 pg/mL) IL-6 levels. Subjects with elevated IL-6 showed a concentration-dependent increase in the prevalence of QTc prolongation, and those presenting with QTc prolongation exhibited higher circulating IL-6 levels. Stepwise multivariate regression analyses demonstrated that increased IL-6 level was significantly associated with a risk of QTc prolongation up to 2 times the odds of the reference category of QTc (e.g. QTc >470 ms men/480 ms women ms: odds ratio, 2.28 [95% CI, 1.12-4.50] for IL-6 >25 pg/mL) regardless of the underlying cause. Specifically, the mean QTc increase observed in the presence of elevated IL-6 was quantitatively comparable (IL-6 >25 pg/mL:+6.7 ms) to that of major recognized QT-prolonging risk factors, such as hypokalemia and history of myocardial infarction.

CONCLUSIONS

Our data provide evidence that a high circulating IL-6 level is a robust risk factor for QTc prolongation in a large cohort of US veterans, supporting a potentially important arrhythmogenic role for this cytokine in the general population.

Structural and Pharmacological Network Focused on MiRNAs Involved in Rheumatoid Arthritis: A Systematic Review

BACKGROUND

Rheumatoid Arthritis (RA) is a chronic autoimmune disease that has a prevalence of over one percent of the world population, causing substantial pain, joint deformity, and functional disability in patients. The identification and measurement of miRNAs are relatively easy to perform. Future studies will corroborate if miRNAs can fulfill their roles as biomarkers with either predictive or diagnostic evaluation of treatment potential and provide actual clinical utility.

METHODS

In the last decade, various advances have been made regarding the identification of the origin and exact functions of miRNAs, allowing us to have a potential use both in the research and clinical fields.

OBJECTIVE

This systematic review aimed to collect, analyze, and improve the current understanding of RA-related miRNAs and their applicability in therapeutics. A bibliographic search of the miRNAs involved in RA was carried out, and through the use of databases, their target genes and small molecules that had some relationship with their expression were searched. The analysis of these data was done through structural network analysis.

RESULTS

During the network analysis, miR-30a, miR-30c, let-7a, miR-144, miR-17-5p, miR-124, miR -23b, miR-23, miR-15a, miR-16 were the most connected, which could be used as possible biomarkers or be candidates for further analysis due to their interaction with other miRNAs and genes.

CONCLUSION

Additionally, this is the first systematic review, in which we proposed that small compounds like toxicants and drugs could have a potential role within RA because they regulate the expression of miRNAs involved in this pathology. Some of these compounds are commonly found as environmental contaminants, and others as drugs. These ideas open a new panorama of understanding RA, proposing possible causes or treatments against this pathology. Therefore, these small molecules would give us some indication of a relationship with RA, thereby helping in seeking causes, treatment, or prevention of this disease.

CONCLUSION

This is the first time it is intended to use structural network analysis to determine possible biomarkers of AR for diagnosis and prognosis through the expression of these miRNAs and their relationship with compounds of daily life.

Comparison of frontal QRS-T angle and inflammatory parameters between the patients with drug-naive first episode psychosis and healthy controls

BACKGROUND

Frontal QRS-T (fQRS-T) angle is a novel marker to predict many cardiovascular diseases. The present study aims to compare the fQRS-T angle of first episode psychosis (FEP) patients and healthy controls (HC) and evaluate the relationship between fQRS-T angle and blood count-related inflammatory markers such as neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and monocyte to high-density lipoprotein cholesterol ratio (MHR).

METHODS

Electrocardiogram (ECG) and complete blood count (CBC) of 63 patients who were diagnosed with drug-naive FEP in the psychiatry clinic of a training and research hospital and 78 healthy controls (HC) individuals who had applied to the health committee polyclinic for recruitment or pre-military examination between 2016 and 2021 were included.

RESULTS

fQRS-T angle was wider in FEP patients (55.5o) than in healthy controls (22o) (p < .001). NLR, PLR, and MHR were higher in FEP patients than in healthy controls (p = .001, p < .001, and p < .001, respectively). fQRS-T angle was positively correlated with NLR (r = 0.52 and p < .001) and MHR (r = 0.39 and p = .002) in FEP patients. NLR (t = 2.196 and p = .032) and MHR (t = 5.469 and p < .001) values were found to be the predictors of fQRS-T angle in FEP patients.

CONCLUSION

In summary, we can conclude that patients with FEP tend to exhibit a wider fQRS-T angle compared to their healthy controls. Additionally, the values of NLR and MHR could potentially serve as useful indicators for predicting the fQRS-T angle in FEP patients. Conducting subsequent long-term studies could provide deeper insights into the interpretation of the fQRS-T angle and its potential connection to cardiovascular diseases in schizophrenia patients.

Secular trends of health care resource utilization and costs between Brugada syndrome and congenital long QT syndrome: A territory-wide study

BACKGROUND

Health care resource utilization (HCRU) and costs are important metrics of health care burden, but they have rarely been explored in the setting of cardiac ion channelopathies.

HYPOTHESIS

This study tested the hypothesis that attendance-related HCRUs and costs differed between patients with Brugada syndrome (BrS) and congenital long QT syndrome (LQTS).

METHODS

This was a retrospective cohort study of consecutive BrS and LQTS patients at public hospitals or clinics in Hong Kong, China. HCRUs and costs (in USD) for Accident and Emergency (A&E), inpatient, general outpatient and specialist outpatient attendances were analyzed between 2001 and 2019 at the cohort level. Comparisons were made using incidence rate ratios (IRRs [95% confidence intervals]).

RESULTS

Over the 19-year period, 516 BrS (median age of initial presentation: 51 [interquartile range: 38-61] years, 92% male) and 134 LQTS (median age of initial presentation: 21 [9-44] years, 32% male) patients were included. Compared to LQTS patients, BrS patients had lower total costs (2 008 126 [2 007 622-2 008 629] vs. 2 343 864 [2 342 828-2 344 900]; IRR: 0.857 [0.855-0.858]), higher costs for A&E attendances (83 113 [83 048-83 177] vs. 70 604 [70 487-70 721]; IRR: 1.177 [1.165-1.189]) and general outpatient services (2,176 [2,166-2,187] vs. 921 [908-935]; IRR: 2.363 [2.187-2.552]), but lower costs for inpatient stay (1 391 624 [1 391 359-1 391 889] vs. 1 713 742 [1 713 166-1 714 319]; IRR: 0.812 [0.810-0.814]) and lower costs for specialist outpatient services (531 213 [531 049-531 376] vs. 558 597 [558268-558926]; IRR: 0.951 [0.947-0.9550]).

CONCLUSIONS

Overall, BrS patients consume 14% less health care resources compared to LQTS patients in terms of attendance costs. BrS patients require more A&E and general outpatient services, but less inpatient and specialist outpatient services than LQTS patients.

Pathophysiology and treatment of adults with arrhythmias in the emergency department, part 2: Ventricular and bradyarrhythmias

PURPOSE

This is the second article in a 2-part series reviewing the pathophysiology and treatment considerations for arrhythmias. Part 1 of the series discussed aspects related to treating atrial arrhythmias. Here in part 2, the pathophysiology of ventricular arrhythmias and bradyarrhythmias and current evidence on treatment approaches are reviewed.

SUMMARY

Ventricular arrhythmias can arise suddenly and are a common cause of sudden cardiac death. Several antiarrhythmics may be effective in management of ventricular arrhythmias, but there is robust evidence to support the use of only a few of these agents, and such evidence was largely derived from trials involving patients with out-of-hospital cardiac arrest. Bradyarrhythmias range from asymptomatic mild prolongation of nodal conduction to severe conduction delays and impending cardiac arrest. Vasopressors, chronotropes, and pacing strategies require careful attention and titration to minimize adverse effects and patient harm.

CONCLUSION

Ventricular arrhythmias and bradyarrhythmias can be consequential and require acute intervention. As experts in pharmacotherapy, acute care pharmacists can participate in providing high-level intervention by aiding in diagnostic workup and medication selection.

Contribution of cytokine-mediated prolongation of QTc interval to the multi-hit theory of Torsade de Pointes

BACKGROUND

Torsade de pointes is a potentially lethal polymorphic ventricular tachyarrhythmia that can occur in the setting of long QT syndrome (LQTS). LQTS is multi-hit in nature and multiple factors combine their effects leading to increased arrhythmic risk. While hypokalemia and multiple medications are accounted for in LQTS, the arrhythmogenic role of systemic inflammation is increasingly recognized but often overlooked. We tested the hypothesis that the inflammatory cytokine interleukin(IL)-6 will significantly increase the incidence of arrhythmia when combined with other pro-arrhythmic conditions (hypokalemia and the psychotropic medication, quetiapine).

METHODS

Guinea pigs were injected intraperitoneally with IL-6/soluble IL-6 receptor and QT changes were measured in vivo. Subsequently, hearts were cannulated via Langendorff perfusion for ex vivo optical mapping measurements of action potential duration (APD90) and arrhythmia inducibility. Computer simulations (MATLAB) were performed to investigate IKr inhibition at varying IL-6 and quetiapine concentrations.

RESULTS

IL-6 prolonged QTc in vivo guinea pigs from 306.74 ± 7.19 ms to 332.60 ± 8.75 ms (n = 8, p = .0021). Optical mapping on isolated hearts demonstrated APD prolongation in IL-6- vs saline groups (3Hz APD90:179.67 ± 2.47 ms vs 153.5 ± 7.86 ms, p = .0357). When hypokalemia was introduced, the APD90 increased to 195.8 ± 5.02 ms[IL-6] and 174.57 ± 10.7 ms[saline] (p = .2797), and when quetiapine was added to hypokalemia to 207.67 ± 3.03 ms[IL-6] and 191.37 ± 9.49 ms[saline] (p = .2449). After the addition of hypokalemia ± quetiapine, arrhythmia was induced in 75% of IL-6-treated hearts (n = 8), while in none of the control hearts (n = 6). Computer simulations demonstrated spontaneous depolarizations at ∼83% aggregate IKr inhibition.

CONCLUSIONS

Our experimental observations strongly suggest that controlling inflammation, specifically IL-6, could be a viable and important route for reducing QT prolongation and arrhythmia incidence in the clinical setting.

COVID-19 mRNA Vaccines: The Molecular Basis of Some Adverse Events

Each injection of any known vaccine results in a strong expression of pro-inflammatory cytokines. This is the result of the innate immune system activation, without which no adaptive response to the injection of vaccines is possible. Unfortunately, the degree of inflammation produced by COVID-19 mRNA vaccines is variable, probably depending on genetic background and previous immune experiences, which through epigenetic modifications could have made the innate immune system of each individual tolerant or reactive to subsequent immune stimulations.We hypothesize that we can move from a limited pro-inflammatory condition to conditions of increasing expression of pro-inflammatory cytokines that can culminate in multisystem hyperinflammatory syndromes following COVID-19 mRNA vaccines (MIS-V). We have graphically represented this idea in a hypothetical inflammatory pyramid (IP) and we have correlated the time factor to the degree of inflammation produced after the injection of vaccines. Furthermore, we have placed the clinical manifestations within this hypothetical IP, correlating them to the degree of inflammation produced. Surprisingly, excluding the possible presence of an early MIS-V, the time factor and the complexity of clinical manifestations are correlated to the increasing degree of inflammation: symptoms, heart disease and syndromes (MIS-V).

Immunity and inflammation in cardiovascular disorders

Recent studies have developed our understanding of the role of the immune system and inflammation in Cardiovascular Disease (CVD), opening new avenues for risk stratification and therapeutic intervention. However, gaps in our knowledge remain. To address this issue, BMC Cardiovascular Disorders has launched a Collection on "Immunity and Inflammation in Cardiovascular Disorders".

COVID-19-associated Brugada pattern electrocardiogram: Systematic review of case reports

AIMS

To summarize published case reports of patients diagnosed with coronavirus disease 2019 (COVID-19) and Brugada pattern electrocardiogram (ECG).

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist were followed. A literature search was conducted using PubMed, EMBASE, and Scopus up until September 2021. The incidence, clinical characteristics, and management outcomes of COVID-19 patients with a Brugada pattern ECG were identified.

RESULTS

A total of 18 cases were collected. The mean age was 47.1 years and 11.1% were women. No patients had prior confirmed diagnosis of Brugada syndrome. The most common presenting clinical symptoms were fever (83.3%), chest pain (38.8%), shortness of breath (38.8%), and syncope (16.6%). All 18 patients presented with type 1 Brugada pattern ECG. Four patients (22.2%) underwent left heart catheterization, and none demonstrated the presence of obstructive coronary disease. The most common reported therapies included antipyretics (55.5%), hydroxychloroquine (27.7%), and antibiotics (16.6%). One patient (5.5%) died during hospitalization. Three patients (16.6%) who presented with syncope received either an implantable cardioverter defibrillator or wearable cardioverter defibrillator at discharge. At follow-up, 13 patients (72.2%) had resolution of type 1 Brugada pattern ECG.

CONCLUSION

COVID-19-associated Brugada pattern ECG seems relatively rare. Most patients had resolution of the ECG pattern once their symptoms have improved. Increased awareness and timely use of antipyretics is warranted in this population.

Pathophysiology of Cav1.3 L-type calcium channels in the heart

Ca²⁺ plays a crucial role in excitation-contraction coupling in cardiac myocytes. Dysfunctional Ca²⁺ regulation alters the force of contraction and causes cardiac arrhythmias. Ca²⁺ entry into cardiomyocytes is mediated mainly through L-type Ca²⁺ channels, leading to the subsequent Ca²⁺ release from the sarcoplasmic reticulum. L-type Ca²⁺ channels are composed of the conventional Ca_v1.2, ubiquitously expressed in all heart chambers, and the developmentally regulated Ca_v1.3, exclusively expressed in the atria, sinoatrial node, and atrioventricular node in the adult heart. As such, Ca_v1.3 is implicated in the pathogenesis of sinoatrial and atrioventricular node dysfunction as well as atrial fibrillation. More recently, Ca_v1.3 de novo expression was suggested in heart failure. Here, we review the functional role, expression levels, and regulation of Ca_v1.3 in the heart, including in the context of cardiac diseases. We believe that the elucidation of the functional and molecular pathways regulating Ca_v1.3 in the heart will assist in developing novel targeted therapeutic interventions for the aforementioned arrhythmias.

The Potential Prognostic, Diagnostic and Therapeutic Targets for Recurrent Arrhythmias in Patients with Coronary Restenosis and Reocclusions After Coronary Stenting

BACKGROUND

The interplay of oxidative stress, proinflammatory microparticles, and proinflammatory cytokines in recurrent arrhythmias is unknown in elderly patients with coronary restenosis and reocclusions after coronary stenting.

OBJECTIVE

This research sought to investigate the potential diagnostic and therapeutic targets for recurrent arrhythmias in patients with coronary restenosis and reocclusions after coronary stenting.

METHODS

We examined whether oxidative stress, proinflammatory microparticles, and proinflammatory cytokines could have effects that lead to recurrent arrhythmias in elderly patients with coronary restenosis and reocclusions. We measured the levels of malondialdehyde (MDA), CD31 + endothelial microparticle (CD31 EMP), CD62E + endothelial microparticle (CD62E + EMP), high-sensitivity C-reactive protein (hs-CRP), interleukin- 1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α), as well as oxidized low-density lipoprotein (OX-LDL), and assessed the effects of relationship between oxidative stress, proinflammatory microparticles, and proinflammatory cytokines on recurrent atrial and ventricular arrhythmias in elderly patients with coronary restenosis and reocclusions after coronary stenting.

RESULTS

The levels of CD31 + EMP, CD62E + EMP, MDA, hs-CRP, IL-1β, IL-6, IL-8, TNF-α and OX-LDL were found to be increased significantly in coronary restenosis + recurrent atrial arrhythmia group compared to without coronary restenosis and coronary restenosis + without recurrent atrial arrhythmia groups, respectively (P < 0.001). Patients in the coronary reocclusion + recurrent ventricular arrhythmia group also exhibited significantly increased levels of CD31 + EMP, CD62E + EMP, MDA, hs-CRP, IL-1β, IL-6, IL-8, TNF-α and OXLDL compared to without coronary reocclusion and coronary reocclusion + without recurrent ventricular arrhythmia groups, respectively (P < 0.001).

CONCLUSION

Proinflammatory microparticles, proinflammatory cytokines, and oxidative stress might act as potential targets for recurrent arrhythmias in patients with coronary restenosis and reocclusions after coronary stenting.

Cardiac damage in autoimmune diseases: Target organ involvement that cannot be ignored

Autoimmune diseases are diseases that cause damage to the body's own tissues as a result of immune dysfunction, often involving multiple organs and systems. The heart is one of the common target organs of autoimmune diseases. The whole structure of the heart can be affected, causing microcirculatory disorders, arrhythmias, pericardial damage, myocarditis, myocardial fibrosis, and impaired valvular function. However, early clinical manifestations of autoimmune heart damage are often overlooked because they are insidious or have no typical features. The damage is often severe and irreversible when symptoms are apparent, even life-threatening. Therefore, early detection and treatment of heart damage in autoimmune diseases is particularly important. Herein, we review the clinical features and mechanisms of cardiac damage in common rheumatic diseases.

Dynamic changes of atrioventricular conduction during Covid-19 infection: Does inflammation matter?

Background

The primary manifestation of COVID-19 infection was pulmonary involvement. However, it can also manifest as a cardiovascular problem.

Methods

We report a case of 82-year-old male COVID-19 patient who experienced atrioventricular (AV) conduction disturbance.

Results

The rhythm was degenerated from sinus rhythm to complete AV block. We observe dynamic AV node dysfunction associated with inflammatory response. His bundle pacing successfully captured distal His region.

Conclusion

The severe inflammatory response during COVID-19 infection might permanently damage cardiac conduction system resulted in a complete AV node block.

Anti-inflammatory effects of cannabidiol against lipopolysaccharides in cardiac sodium channels

BACKGROUND

Sepsis, caused by a dysregulated host response to infections, can lead to cardiac arrhythmias. However, the mechanisms underlying sepsis-induced inflammation, and how inflammation provokes cardiac arrhythmias, are not well understood. We hypothesized that CBD may ameliorate lipopolysaccharides (LPS)-induced cardiotoxicity via Toll-like receptor 4 (TLR-4) and cardiac sodium channels (Nav1.5).

METHODS AND RESULTS

We incubated human immune cells (THP-1 macrophages) with LPS for 24 hours, then extracted the THP-1 incubation media. ELISA assay showed that LPS (1 or 5 μg/ml), in a concentration-dependent manner, or MPLA (TLR-4 agonist, 5 μg/ml) stimulated the THP-1 cells to release inflammatory cytokines (TNF-α and IL-6). Prior incubation (4 hours) with cannabidiol (CBD: 5 μM) or C34 (TLR-4 antagonist: 5 μg/ml) inhibited LPS and MPLA-induced release of both IL-6 and TNF-α. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) were subsequently incubated for 24 hours in the media extracted from THP-1 cells incubated with LPS, MPLA alone, or in combination with CBD or C34. Voltage-clamp experiments showed a right shift in the voltage dependence of Nav1.5 activation, steady state fast inactivation (SSFI), increased persistent current and prolonged in silico action potential duration in hiSPC-CM incubated in the LPS or MPLA-THP-1 media. Co-incubation with CBD or C34 rescued the biophysical dysfunction caused by LPS and MPLA.

CONCLUSION

Our results suggest that CBD may protect against sepsis-induced inflammation and subsequent arrhythmias through (i) inhibition of the release of inflammatory cytokines, antioxidant and anti-apoptotic effects and/or (ii) direct effect on Nav1.5.

Electrocardiogram Signal Classification Based on Mix Time-Series Imaging

Arrhythmia is a significant cause of death, and it is essential to analyze the electrocardiogram (ECG) signals as this is usually used to diagnose arrhythmia. However, the traditional time series classification methods based on ECG ignore the nonlinearity, temporality, or other characteristics inside these signals. This paper proposes an electrocardiogram classification method that encodes one-dimensional ECG signals into the three-channel images, named ECG classification based on Mix Time-series Imaging (EC-MTSI). Specifically, this hybrid transformation method combines Gramian angular field (GAF), recurrent plot (RP), and tiling, preserving the original ECG time series’ time dependence and correlation. We use a variety of neural networks to extract features and perform feature fusion and classification. This retains sufficient details while emphasizing local information. To demonstrate the effectiveness of the EC-MTSI, we conduct abundant experiments in a commonly-used dataset. In our experiments, the general accuracy reached 93.23%, and the accuracy of identifying high-risk arrhythmias of ventricular beats and supraventricular beats alone are as high as 97.4% and 96.3%, respectively. The results reveal that the proposed method significantly outperforms the existing approaches.

Mechanistic Insights Into Inflammation-Induced Arrhythmias: A Simulation Study

Cardiovascular diseases are the primary cause of death of humans, and among these, ventricular arrhythmias are the most common cause of death. There is plausible evidence implicating inflammation in the etiology of ventricular fibrillation (VF). In the case of systemic inflammation caused by an overactive immune response, the induced inflammatory cytokines directly affect the function of ion channels in cardiomyocytes, leading to a prolonged action potential duration (APD). However, the mechanistic links between inflammatory cytokine-induced molecular and cellular influences and inflammation-associated ventricular arrhythmias need to be elucidated. The present study aimed to determine the potential impact of systemic inflammation on ventricular electrophysiology by means of multiscale virtual heart models. The experimental data on the ionic current of three major cytokines [i.e., tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1β), and interleukin-6 (IL-6)] were incorporated into the cell model, and the effects of each cytokine and their combined effect on the cell action potential (AP) were evaluated. Moreover, the integral effect of these cytokines on the conduction of excitation waves was also investigated in a tissue model. The simulation results suggested that inflammatory cytokines significantly prolonged APD, enhanced the transmural and regional repolarization heterogeneities that predispose to arrhythmias, and reduced the adaptability of ventricular tissue to fast heart rates. In addition, simulated pseudo-ECGs showed a prolonged QT interval—a manifestation consistent with clinical observations. In summary, the present study provides new insights into ventricular arrhythmias associated with inflammation.

Interleukin-6 Elevation Is a Key Pathogenic Factor Underlying COVID-19-Associated Heart Rate-Corrected QT Interval Prolongation

Background

Heart rate-corrected QT interval (QTc) prolongation is prevalent in patients with severe coronavirus disease 2019 (COVID-19) and is associated with poor outcomes. Recent evidence suggests that the exaggerated host immune-inflammatory response characterizing the disease, specifically interleukin-6 (IL-6) increase, may have an important role, possibly via direct effects on cardiac electrophysiology. The aim of this study was to dissect the short-term discrete impact of IL-6 elevation on QTc in patients with severe COVID-19 infection and explore the underlying mechanisms.

Methods

We investigated the following mechanisms: (1) the QTc duration in patients with COVID-19 during the active phase and recovery, and its association with C-reactive protein (CRP) and IL-6 levels; (2) the acute impact of IL-6 administration on QTc in an in vivo guinea pig model; and (3) the electrophysiological effects of IL-6 on ventricular myocytes in vitro.

Results

In patients with active severe COVID-19 and elevated IL-6 levels, regardless of acute myocardial injury/strain and concomitant QT-prolonging risk factors, QTc was significantly prolonged and rapidly normalized in correlation with IL-6 decrease. The direct administration of IL-6 in an in vivo guinea pig model acutely prolongs QTc duration. Moreover, ventricular myocytes incubated in vitro with IL-6 show evident prolongation in the action potential, along with significant inhibition in the rapid delayed rectifier potassium current (I_Kr).

Conclusion

For the first time, we demonstrated that in severe COVID-19, systemic inflammatory activation can per se promote QTc prolongation via IL-6 elevation, leading to ventricular electric remodeling. Despite being transitory, such modifications may significantly contribute to arrhythmic events and associated poor outcomes in COVID-19. These findings provide a further rationale for current anti-inflammatory treatments for COVID-19, including IL-6-targeted therapies.

A novel Troponin I mutation associated with severe restrictive cardiomyopathy-a case report of a 27-year-old woman with fatigue

BACKGROUND

Restrictive cardiomyopathy is rare and heterogeneous in origin, clinical manifestation, and prognosis. Familial forms have, amongst others, been associated with mutations in the TNNI3 gene. We present a case of familial restrictive cardiomyopathy associated with a novel TNNI3 mutation including longitudinal follow-up.

CASE SUMMARY

A 27-year-old woman was evaluated for fatigue in the context of a family history of sudden cardiac death. Echocardiography was normal except for mild left atrial dilatation. Focused genetic screening, limited to the most common genes associated with cardiomyopathy, was unremarkable in 2006. In biopsy, mild inflammatory cardiomyopathy was diagnosed, and the patient was discharged. Thirteen years later, rapid clinical deterioration occurred in the context of new-onset atrial fibrillation (AF). Echocardiography now showed gross bi-atrial dilatation and evidence of diastolic dysfunction. Based on haemodynamic tracings during angiography, a diagnosis of restrictive cardiomyopathy was made. In 2018, next-generation sequencing revealed the hitherto undescribed Troponin I variant Lys193Glu in a functionally critical domain. Haemodynamic stabilization was achieved by pulmonary vein isolation. Until now, the patient remains symptom free under diuretic treatment.

DISCUSSION

Diagnosis of restrictive cardiomyopathy is complicated by often oligosymptomatic early presentation and a diverse clinical picture. Thorough medical and family history and early invasive haemodynamic tracing are indispensable in diagnosis. Therapy-refractory AF should raise suspicion. Reporting of longitudinal follow-up cases is essential to better understand the early symptoms, development, and prognosis of this rare disease. Broad genetic testing in unclear cases has become more available and affordable and should be considered early in the diagnostic workflow.

Antiviral and anti-inflammatory drugs to combat COVID-19: Effects on cardiac ion channels and risk of ventricular arrhythmias

Introduction: Drugs with no indication for the treatment of cardiovascular diseases (e.g., drugs employed to treat COVID-19) can increase the risk of arrhythmias. Of interest, a six-fold increase in the number of arrhythmic events was reported in patients with severe COVID-19. In this study, we reviewed (i) the pro-arrhythmic action of drugs given to patients with COVID-19 infection, and (ii) the effects of inflammatory cytokines on cardiac ion channels and possible generation of arrhythmias.

Methods: We conducted a literature search on the drugs with purported or demonstrated efficacy against COVID-19 disease, emphasizing the mechanisms by which anti-COVID-19 drugs and inflammatory cytokines interfere with cardiac ion channels.

Results:Antibiotics (azithromycin), antimalarials (hydroxychloroquine, chloroquine), antivirals (ritonavir/lopinavir, atazanavir), and some of the tyrosine kinase inhibitors (vandetanib) could induce long QT and increase risk for ventricular arrhythmias. The pro-arrhythmic action results from drug-induced inhibition of Kv11.1 (hERG) channels interfering with the repolarizing potassium IKr currents, leading to long QT and increased risk of triggered arrhythmias. At higher concentrations, these drugs may interfere with IKs, IK1, and/or Ito potassium currents, and even inhibit sodium (INa) and calcium (ICa) currents, inducing additional cardiac toxicity. Ibrutinib, an inhibitor of Bruton’s TK, increased the incidence of atrial fibrillation and ventricular tachycardia associated with a short QT interval. Inflammatory cytokines IL-6 and TNF-α inhibit IKr and Ito repolarizing potassium currents. High levels of inflammatory cytokines could contribute to the arrhythmic events. For remdesivir, favipiravir, dexamethasone, tocilizumab, anakinra, baricitinib, and monoclonal antibodies (bamlanivimab, etesevimab, and casirivimab), no evidence supports significant effects on cardiac ion channels, changes in the QT interval, and increased risk for ventricular arrhythmias.

Conclusion: This study supports the concept of hERG channel promiscuity. Different drug classes given to COVID-19 patients might delay repolarization, and increase the risk of ventricular arrhythmias. The presence of comorbid pro-arrhythmic disease states, and elevated levels of pro-arrhythmic cytokines, could increase the risk of ventricular arrhythmias. Discontinuation of nonessential drugs and correction of electrolyte abnormalities could prevent severe ventricular arrhythmias. Altogether, the most effective therapies against COVID-19 (remdesivir, dexamethasone, monoclonal antibodies) lack pro-arrhythmic activity.

Arrhythmogenic mechanisms of interleukin-6 combination with hydroxychloroquine and azithromycin in inflammatory diseases

Inflammatory diseases including COVID-19 are associated with a cytokine storm characterized by high interleukin-6 (IL-6) titers. In particular, while recent studies examined COVID-19 associated arrhythmic risks from cardiac injury and/or from pharmacotherapy such as the combination of azithromycin (AZM) and hydroxychloroquine (HCQ), the role of IL-6 per se in increasing the arrhythmic risk remains poorly understood. The objective is to elucidate the electrophysiological basis of inflammation-associated arrhythmic risk in the presence of AZM and HCQ. IL-6, AZM and HCQ were concomitantly administered to guinea pigs in-vivo and in-vitro. Electrocardiograms, action potentials and ion-currents were analyzed. IL-6 alone or the combination AZM + HCQ induced mild to moderate reduction in heart rate, PR-interval and corrected QT (QTc) in-vivo and in-vitro. Notably, IL-6 alone was more potent than the combination of the two drugs in reducing heart rate, increasing PR-interval and QTc. In addition, the in-vivo or in-vitro combination of IL-6 + AZM + HCQ caused severe bradycardia, conduction abnormalities, QTc prolongation and asystole. These electrocardiographic abnormalities were attenuated in-vivo by tocilizumab (TCZ), a monoclonal antibody against IL-6 receptor, and are due in part to the prolongation of action potential duration and selective inhibition of Na⁺, Ca²⁺ and K⁺ currents. Inflammation confers greater risk for arrhythmia than the drug combination therapy. As such, in the setting of elevated IL-6 during inflammation caution must be taken when co-administering drugs known to predispose to fatal arrhythmias and TCZ could be an important player as a novel anti-arrhythmic agent. Thus, identifying inflammation as a critical culprit is essential for proper management.

Transient Hypogonadism Is Associated With Heart Rate-Corrected QT Prolongation and Torsades de Pointes Risk During Active Systemic Inflammation in Men

Background

Systemic inflammation and male hypogonadism are 2 increasingly recognized “nonconventional” risk factors for long‐QT syndrome and torsades de pointes (TdP). Specifically, inflammatory cytokines prolong, while testosterone shortens the heart rate–corrected QT interval (QTc) via direct electrophysiological effects on cardiomyocytes. Moreover, several studies demonstrated important interplays between inflammation and reduced gonad function in men. We hypothesized that, during inflammatory activation in men, testosterone levels decrease and that this enhances TdP risk by contributing to the overall prolonging effect of inflammation on QTc.

Methods and Results

We investigated (1) the levels of sex hormones and their relationship with inflammatory markers and QTc in male patients with different types of inflammatory diseases, during active phase and recovery; and (2) the association between inflammatory markers and sex hormones in a cohort of male patients who developed extreme QTc prolongation and TdP, consecutively collected over 10 years. In men with active inflammatory diseases, testosterone levels were significantly reduced, but promptly normalized in association with the decrease in C‐reactive protein and interleukin‐6 levels. Reduction of testosterone levels, which also inversely correlated with 17‐β estradiol over time, significantly contributed to inflammation‐induced QTc prolongation. In men with TdP, both active systemic inflammation and hypogonadism were frequently present, with significant correlations between C‐reactive protein, testosterone, and 17‐β estradiol levels; in these patients, increased C‐reactive protein and reduced testosterone were associated with a worse short‐term outcome of the arrhythmia.

Conclusions

During systemic inflammatory activation, interleukin‐6 elevation is associated with reduced testosterone levels in males, possibly deriving from an enhanced androgen‐to‐estrogen conversion. While transient, inflammatory hypotestosteronemia is significantly associated with an increased long‐QT syndrome/TdP risk in men.

Unravelling Atrioventricular Block Risk in Inflammatory Diseases: Systemic Inflammation Acutely Delays Atrioventricular Conduction via a Cytokine-Mediated Inhibition of Connexin43 Expression

Background

Recent data suggest that systemic inflammation can negatively affect atrioventricular conduction, regardless of acute cardiac injury. Indeed, gap‐junctions containing connexin43 coupling cardiomyocytes and inflammation‐related cells (macrophages) are increasingly recognized as important factors regulating the conduction in the atrioventricular node. The aim of this study was to evaluate the acute impact of systemic inflammatory activation on atrioventricular conduction, and elucidate underlying mechanisms.

Methods and Results

We analyzed: (1) the PR‐interval in patients with inflammatory diseases of different origins during active phase and recovery, and its association with inflammatory markers; (2) the existing correlation between connexin43 expression in the cardiac tissue and peripheral blood mononuclear cells (PBMC), and the changes occurring in patients with inflammatory diseases over time; (3) the acute effects of interleukin(IL)‐6 on atrioventricular conduction in an in vivo animal model, and on connexin43 expression in vitro. In patients with elevated C‐reactive protein levels, atrioventricular conduction indices are increased, but promptly normalized in association with inflammatory markers reduction, particularly IL‐6. In these subjects, connexin43 expression in PBMC, which is correlative of that measured in the cardiac tissue, inversely associated with IL‐6 changes. Moreover, direct IL‐6 administration increased atrioventricular conduction indices in vivo in a guinea pig model, and IL‐6 incubation in both cardiomyocytes and macrophages in culture, significantly reduced connexin43 proteins expression.

Conclusions

The data evidence that systemic inflammation can acutely worsen atrioventricular conduction, and that IL‐6‐induced down‐regulation of cardiac connexin43 is a mechanistic pathway putatively involved in the process. Though reversible, these alterations could significantly increase the risk of severe atrioventricular blocks during active inflammatory processes.

Anti-Ro/SSA Antibodies and the Autoimmune Long-QT Syndrome

Autoimmunity is increasingly recognized as a novel pathogenic mechanism for cardiac arrhythmias. Several arrhythmogenic autoantibodies have been identified, cross-reacting with different types of surface proteins critically involved in the cardiomyocyte electrophysiology, primarily ion channels (autoimmune cardiac channelopathies). Specifically, some of these autoantibodies can prolong the action potential duration leading to acquired long-QT syndrome (LQTS), a condition known to increase the risk of life-threatening ventricular arrhythmias, particularly Torsades de Pointes (TdP). The most investigated form of autoimmune LQTS is associated with the presence of circulating anti-Ro/SSA-antibodies, frequently found in patients with autoimmune diseases (AD), but also in a significant proportion of apparently healthy subjects of the general population. Accumulating evidence indicates that anti-Ro/SSA-antibodies can markedly delay the ventricular repolarization via a direct inhibitory cross-reaction with the extracellular pore region of the human-ether-a-go-go-related (hERG) potassium channel, resulting in a higher propensity for anti-Ro/SSA-positive subjects to develop LQTS and ventricular arrhythmias/TdP. Recent population data demonstrate that the risk of LQTS in subjects with circulating anti-Ro/SSA antibodies is significantly increased independent of a history of overt AD, intriguingly suggesting that these autoantibodies may silently contribute to a number of cases of ventricular arrhythmias and cardiac arrest in the general population. In this review, we highlight the current knowledge in this topic providing complementary basic, clinical and population health perspectives.

Autonomic Modulation for Treatment of Repolarization Alternans and Refractory Ventricular Electrical Storm

Macroscopic T-wave alternans (TWA) is a rare finding on surface electrocardiogram and has been associated with an increased risk of impending sudden cardiac death. We highlight a case of macroscopic TWA in a patient with markedly prolonged QTc interval preceding ventricular electrical storm, which was refractory to medical management. Autonomic modulation of the stellate ganglion resulted in improvement in both TWA and QTc interval. (Level of Difficulty: Advanced.).

COVID-19 induced ventricular tachycardia storm unmasking a clinically silent cardiomyopathy: a case report

Background

Coronavirus disease (COVID-19) is a systemic illness characterized by raging impact of cytokine storm on multiple organs. This may trigger malignant ventricular arrhythmias and unmask a clinically silent cardiomyopathy.

Case summary

A 57-year-old gentleman, known case of hyperthyroidism and diabetes, was referred to our emergency department with history of two ventricular tachycardia (VT) episodes requiring direct current cardioversion in last 3 h followed by another episode in our emergency department that was cardioverted. There was no past history of cardiac illness. His 12-lead electrocardiogram (during sinus rhythm) along with screening echocardiography suggested Arrhythmogenic right ventricular cardiomyopathy (ARVC). He was coincidentally found to be COVID-19 positive by reverse transcription-polymerase chain reaction (RT-PCR) as part of our routine screening. However, he had no fever or respiratory complaints. We noted raised systemic inflammatory markers and cardiac troponin T which progressively increased over the next 4 weeks paralleled by an increase in ventricular premature contraction burden and thereafter started decreasing and returned to baseline by 6th week when the patient became COVID-19 negative by RT-PCR. Subsequently, a single-chamber automated implantable cardioverter-defibrillator implantation was done following which there was a transient increase in these biomarkers that subsided spontaneously. The patient is asymptomatic during 6 weeks of follow-up.

Discussion

COVID-19-associated cytokine surge triggering VT storm and unmasking a clinically silent ARVC has not yet been reported. The case highlights a life-threatening presentation of COVID-19 and indicates a probable link between inflammation and arrhythmogenicity.

Conductance heterogeneities induced by multistability in the dynamics of coupled cardiac gap junctions

In this paper, we study the propagation of the cardiac action potential in a one-dimensional fiber, where cells are electrically coupled through gap junctions (GJs). We consider gap junctional gate dynamics that depend on the intercellular potential. We find that different GJs in the tissue can end up in two different states: a low conducting state and a high conducting state. We first present evidence of the dynamical multistability that occurs by setting specific parameters of the GJ dynamics. Subsequently, we explain how the multistability is a direct consequence of the GJ stability problem by reducing the dynamical system's dimensions. The conductance dispersion usually occurs on a large time scale, i.e., thousands of heartbeats. The full cardiac model simulations are computationally demanding, and we derive a simplified model that allows for a reduction in the computational cost of four orders of magnitude. This simplified model reproduces nearly quantitatively the results provided by the original full model. We explain the discrepancies between the two models due to the simplified model's lack of spatial correlations. This simplified model provides a valuable tool to explore cardiac dynamics over very long time scales. That is highly relevant in studying diseases that develop on a large time scale compared to the basic heartbeat. As in the brain, plasticity and tissue remodeling are crucial parameters in determining the action potential wave propagation's stability.

Proton Pump Inhibitors Directly Block hERG-Potassium Channel and Independently Increase the Risk of QTc Prolongation in a Large Cohort of US Veterans

[Figure: see text].

Cardiac Biomarkers and Autoantibodies in Endurance Athletes: Potential Similarities with Arrhythmogenic Cardiomyopathy Pathogenic Mechanisms

The “Extreme Exercise Hypothesis” states that when individuals perform training beyond the ideal exercise dose, a decline in the beneficial effects of physical activity occurs. This is due to significant changes in myocardial structure and function, such as hemodynamic alterations, cardiac chamber enlargement and hypertrophy, myocardial inflammation, oxidative stress, fibrosis, and conduction changes. In addition, an increased amount of circulating biomarkers of exercise-induced damage has been reported. Although these changes are often reversible, long-lasting cardiac damage may develop after years of intense physical exercise. Since several features of the athlete’s heart overlap with arrhythmogenic cardiomyopathy (ACM), the syndrome of “exercise-induced ACM” has been postulated. Thus, the distinction between ACM and the athlete’s heart may be challenging. Recently, an autoimmune mechanism has been discovered in ACM patients linked to their characteristic junctional impairment. Since cardiac junctions are similarly impaired by intense physical activity due to the strong myocardial stretching, we propose in the present work the novel hypothesis of an autoimmune response in endurance athletes. This investigation may deepen the knowledge about the pathological remodeling and relative activated mechanisms induced by intense endurance exercise, potentially improving the early recognition of whom is actually at risk.

Otherwise Unexplained Transient QTc Prolongation in a Patient Admitted with COVID Disease

Background. Several cardiovascular manifestations of coronavirus disease 2019 (COVID-19) have been previously described. QT prolongation has been reported in COVID-19 infection in association with medications such as azithromycin, hydroxychloroquine, and chloroquine but has not previously been reported as a direct result of COVID-19 infection. Case summary. We report the case of a 65-year-old female who developed a prolonged corrected QT interval (QTc) during a hospital admission with COVID-19. This patient was not on any QT prolonging treatment, serum electrolytes were normal, and there was no identifiable reversible cause for the QTc lengthening. Daily serial ECGs during admission showed resolution of the ventricular repolarization abnormality in synchronization with resolution of her COVID-19 viral illness. Discussions. Although there have been reports of QTc prolongation in COVID-19 patients, previous reports of this are for patients receiving medication that causes QT prolongation. This case uniquely demonstrates the development and resolution of this temporary ventricular repolarization abnormality in a patient with a structurally normal heart with no evidence of myocardial fibrosis or edema on cardiac MRI, that is unexplained by other confounding factors, such as medication. This suggests there may be a direct association between COVID-19 and temporary QTc prolongation.

Arrhythmia prevalence among patients with polymyositis-dermatomyositis in the United States: An observational study

BACKGROUND

Systemic inflammation has been associated with atherosclerotic cardiovascular diseases (ASCVD) and arrhythmia occurrence in rheumatologic conditions such as rheumatoid arthritis. Polymyositis and dermatomyositis (PD) are rare rheumatologic conditions characterized by symmetrical proximal muscle weakness and, in the case of dermatomyositis, cutaneous eruption. Although there is literature associating PD with ASCVD, no population-level studies have analyzed arrhythmia risk in PD.

OBJECTIVE

The purpose of this study was to assess the prevalence of arrhythmia and its subtypes by age and sex in patients with PD and to determine associations between arrhythmia and PD.

METHODS

This retrospective cohort study included adults for whom hospitalizations had been recorded in the National Inpatient Sample database in the United States between 2016 and 2018. Patients with PD were matched (1:10) by age to patients without PD. Prevalence of arrhythmia was calculated in the 2 groups and compared by sex and age groups. Associations between PD and arrhythmia were determined after adjustment for common arrhythmia risk factors.

RESULTS

From 107,001,355 hospitalizations, 32,085 adults with PD were matched to 320,850 controls. Patients with PD aged <70 years had a higher prevalence of arrhythmia and higher adjusted odds of arrhythmia compared with controls. This increased risk was only seen for supraventricular arrhythmias. Adults with PD had increased odds of in-hospital mortality if they had an arrhythmia diagnosis (odds ratio 3.3; 95% confidence interval 2.5-4.5; P <.001).

CONCLUSION

We found a higher prevalence and odds of arrhythmias, particularly supraventricular arrhythmias, in young and middle-aged patients with PD compared with matched controls. Arrhythmias were associated with significant mortality among patients with PD.

Acquired Long QT Syndrome and Torsades de Pointes after Mitral Valve Replacement Surgery

Acquired long QT syndrome (aLQTS) can occur in up to one third of patients undergoing cardiac surgery and is often undisclosed. We present a case of a 55-year-old male patient admitted to our center for mitral valve replacement surgery, and, during the postoperative period, a long QT greater than 600 ms was confirmed and in the Holter monitoring Torsade de Pointes (TdP) was evidenced. The patient received appropriate medical treatment and was discharge in stable clinical conditions.

Ryanodine receptor and immune-related molecules in diabetic cardiomyopathy

Hyperglycaemia is a major aetiological factor in the development of diabetic cardiomyopathy. Excessive hyperglycaemia increases the levels of reactive carbonyl species (RCS), reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the heart and causes derangements in calcium homeostasis, inflammation and immune‐system disorders. Ryanodine receptor 2 (RyR2) plays a key role in excitation–contraction coupling during heart contractions, including rhythmic contraction and relaxation of the heart. Cardiac inflammation has been indicated in part though interleukin 1 (IL‐1) signals, supporting a role for B and T lymphocytes in diabetic cardiomyopathy. Some of the post‐translational modifications of the ryanodine receptor (RyR) by RCS, ROS and RNS stress are known to affect its gating and Ca²⁺ sensitivity, which contributes to RyR dysregulation in diabetic cardiomyopathy. RyRs and immune‐related molecules are important signalling species in many physiological and pathophysiological processes in various heart and cardiovascular diseases. However, little is known regarding the mechanistic relationship between RyRs and immune‐related molecules in diabetes, as well as the mechanisms mediating complex communication among cardiomyocytes, fibroblasts and immune cells. This review highlights new findings on the complex cellular communications in the pathogenesis and progression of diabetic cardiomyopathy. We discuss potential therapeutic applications targeting RyRs and immune‐related molecules in diabetic complications.

Torsades de pointes episode in a woman with high-grade fever and inflammatory activation: A case report

BACKGROUND

QT interval prolongation can induce torsades de pointes (TdP), a potentially fatal ventricular arrhythmia. Recently, an increasing number of non-cardiac drugs have been found to cause QT prolongation and/or TdP onset. Moreover, recent findings have demonstrated the key roles of systemic inflammatory activation and fever in promoting long-QT syndrome (LQTS) and TdP development.

CASE SUMMARY

A 30-year-old woman was admitted with a moderate to high-grade episodic fever for two weeks. The patient was administered with multiple antibiotics after hospitalization but still had repeating fever and markedly elevated C-reactive protein. Once after a high fever, the patient suddenly lost consciousness, and electrocardiogram (ECG) showed transient TdP onset after frequent premature ventricular contraction. The patient recovered sinus rhythm and consciousness spontaneously, and post-TdP ECG revealed a prolonged QTc interval of 560 ms. The patient’s clinical manifestations and unresponsiveness to the antibiotics led to the final diagnosis of adult-onset Still’s disease (AOSD). There was no evidence of cardiac involvement. After the AOSD diagnosis, discontinuation of antibiotics and immediate initiation of intravenous dexamethasone administration resulted in the normal temperature and QTc interval. The genetic analysis identified that the patient and her father had heterozygous mutations in KCNH2 (c.1370C>T) and AKAP9 (c.7725A>C). During the 2-year follow-up period, the patient had no recurrence of any arrhythmia and maintained normal QTc interval.

CONCLUSION

This case study highlights the risk of systemic inflammatory activation and antibiotic-induced TdP/LQTS onset. Genetic analysis should be considered to identify individuals at high risk of developing TdP.

Inflammation as a Risk Factor in Cardiotoxicity: An Important Consideration for Screening During Drug Development

Numerous commonly prescribed drugs, including antiarrhythmics, antihistamines, and antibiotics, carry a proarrhythmic risk and may induce dangerous arrhythmias, including the potentially fatal Torsades de Pointes. For this reason, cardiotoxicity testing has become essential in drug development and a required step in the approval of any medication for use in humans. Blockade of the hERG K⁺ channel and the consequent prolongation of the QT interval on the ECG have been considered the gold standard to predict the arrhythmogenic risk of drugs. In recent years, however, preclinical safety pharmacology has begun to adopt a more integrative approach that incorporates mathematical modeling and considers the effects of drugs on multiple ion channels. Despite these advances, early stage drug screening research only evaluates QT prolongation in experimental and computational models that represent healthy individuals. We suggest here that integrating disease modeling with cardiotoxicity testing can improve drug risk stratification by predicting how disease processes and additional comorbidities may influence the risks posed by specific drugs. In particular, chronic systemic inflammation, a condition associated with many diseases, affects heart function and can exacerbate medications’ cardiotoxic effects. We discuss emerging research implicating the role of inflammation in cardiac electrophysiology, and we offer a perspective on how in silico modeling of inflammation may lead to improved evaluation of the proarrhythmic risk of drugs at their early stage of development.

Drug-Associated QTc Prolongation in Geriatric Hospitalized Patients: A Cross-Sectional Study in Internal Medicine

Objective

The primary objectives of this prospective cross-sectional study were to estimate the prevalence of drug-related long QT syndrome (LQTS) and the prevalence of use of QT-prolonging drugs in older patients admitted to an internal medicine unit.

Methods

We screened consecutive patients hospitalized in an internal medicine unit over a 2-year period. A 12-lead electrocardiogram using an electrocardiograph with automated measurement of QT interval was recorded. Patient characteristics (age, sex, body mass index), drug treatments, and variables associated with QT interval prolongation, including hypothyroidism, type 2 diabetes mellitus, and cardiac disease, were also recorded. In addition, we also measured serum levels of potassium, calcium, magnesium, and creatinine at admission. The list of medications known to cause or to contribute to LQTS was obtained from CredibleMeds^®.

Results

A total of 243 patients were enrolled: mean ± standard deviation age, 79.65 ± 8.27 years; males, n = 121 (40.8%); mean corrected QT (QTc) interval, 453.70 ± 43.77 ms. Overall, 89/243 (36.6%) patients had a prolonged QTc interval, with 29/243 (11.9%) having QTc interval prolongation > 500 ms (11.9%). A vast majority were prescribed at least one QT-prolonging drug (218/243 [89.7%]), whereas 74/218 (30.5%) were receiving at least one medication with a known risk of Torsades des Pointes (TdP). Proton pump inhibitors were the second most commonly prescribed class of drugs. After logistic regression, male sex was independently associated with LQTS (odds ratio 2.85; 95% confidence interval 1.56–5.22; p = 0.001).

Conclusions

The prevalence of LQTS with QTc interval > 500 ms in geriatric inpatients was > 10%, and QT-prolonging drugs were frequently used on admission (more than 30% of patients were receiving drugs with a known risk of TdP).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40801-021-00234-x.

Flavonoids and hERG channels: Friends or foes?

The cardiac action potential is regulated by several ion channels. Drugs capable to block these channels, in particular the human ether-à-go-go-related gene (hERG) channel, also known as K_V11.1 channel, may lead to a potentially lethal ventricular tachyarrhythmia called "Torsades de Pointes". Thus, evaluation of the hERG channel off-target activity of novel chemical entities is nowadays required to safeguard patients as well as to avoid attrition in drug development. Flavonoids, a large class of natural compounds abundantly present in food, beverages, herbal medicines, and dietary food supplements, generally escape this assessment, though consumed in consistent amounts. Continuously growing evidence indicates that these compounds may interact with the hERG channel and block it. The present review, by examining numerous studies, summarizes the state-of-the-art in this field, describing the most significant examples of direct and indirect inhibition of the hERG channel current operated by flavonoids. A description of the molecular interactions between a few of these natural molecules and the Rattus norvegicus channel protein, achieved by an in silico approach, is also presented.

Syncope due to non-sustained episodes of Torsade de Pointes associated to androgen-deprivation therapy use: a case presentation

BACKGROUND

Abiraterone is a medication frequently used for metastatic castrate-resistant prostate cancer. We report a case of non-sustained episodes of TdP associated with severe hypokalemia due to androgen-deprivation therapy. Few case presentations describe this association; the novelty lies in the potentially lethal cardiovascular events among cancer patients receiving hormonal therapy.

CASE PRESENTATION

A 70-year-old male presented with recurrent syncope without prodrome. ECG revealed frequent ventricular ectopy, non-sustained episodes of TdP, and severe hypomagnesemia and hypokalemia. During potassium and magnesium infusion for repletion, the patient underwent temporary transvenous atrial pacing. As part of the work-up, coronary angiography revealed a mild coronary artery disease, and transthoracic echocardiogram showed a moderately depressed ejection fraction. After electrolyte disturbances were corrected, the QT interval normalized, and transvenous pacing was no longer necessary. Abiraterone was discontinued during the admission, and the patient returned to baseline.

CONCLUSIONS

Cancer treatment is complex and requires a multidisciplinary approach. We presented a case of non-sustained TdP associated with androgen-deprivation therapy in an elderly patient with mild coronary artery disease and moderately reduced ejection fraction. Close follow-up and increased awareness are required in patients with hormonal treatment, especially in the setting of other cardiovascular risk factors.

Risk of QTc Interval Prolongation Associated With Circulating Anti-Ro/SSA Antibodies Among US Veterans: An Observational Cohort Study

Background

Anti‐Sjögren's syndrome‐related antigen A‐antibodies (anti‐Ro/SSA‐antibodies) are responsible for a novel form of acquired long‐QT syndrome, owing to autoimmune‐mediated inhibition of cardiac human ether‐a‐go‐go‐related gene‐potassium channels. However, current evidence derives only from basic mechanistic studies and relatively small sample‐size clinical investigations. Hence, the aim of our study is to estimate the risk of QTc prolongation associated with the presence of anti‐Ro/SSA‐antibodies in a large population of unselected subjects.

Methods and Results

This is a retrospective observational cohort study using the Veterans Affairs Informatics and Computing Infrastructure. Participants were veterans who were tested for anti‐Ro/SSA status and had an ECG. Descriptive statistics and univariate and multivariate logistic regression analyses were performed to identify risk factors for heart rate‐corrected QT interval (QTc) prolongation. The study population consisted of 7339 subjects (61.4±12.2 years), 612 of whom were anti‐Ro/SSA‐positive (8.3%). Subjects who were anti‐Ro/SSA‐positive showed an increased prevalence of QTc prolongation, in the presence of other concomitant risk factors (crude odds ratios [OR], 1.67 [1.26–2.21] for QTc >470/480 ms; 2.32 [1.54–3.49] for QTc >490 ms; 2.77 [1.66–4.60] for QTc >500 ms), independent of a connective tissue disease history. Adjustments for age, sex, electrolytes, cardiovascular risk factors/diseases, and medications gradually attenuated QTc prolongation estimates, particularly when QT‐prolonging drugs were added to the model. Nevertheless, stepwise‐fully adjusted OR for the higher cutoffs remained significantly increased in anti‐Ro/SSA‐positive subjects, particularly for QTc >500 ms (2.27 [1.34–3.87]).

Conclusions

Anti‐Ro/SSA‐antibody positivity was independently associated with an increased risk of marked QTc prolongation in a large cohort of US veterans. Our data suggest that within the general population individuals who are anti‐Ro/SSA‐positive may represent a subgroup of patients particularly predisposed to ventricular arrhythmias/sudden cardiac death.

The functional medicine approach to atrial fibrillation: can a cure for atrial fibrillation be found in the gut?

PURPOSE OF REVIEW

The importance of addressing the proximal causes of atrial fibrillation is recognized, yet frustration with the currently applied preventive measures is high. This review describes the functional medicine model (FMM), which identifies the proximal causes of atrial fibrillation at the level of gene-environment interaction.

RECENT FINDINGS

The pathological processes leading to atrial fibrillation sustaining disorder have been elucidated in translational studies and are described as 'nodal points.' Examples are inflammation, oxidative stress, autoimmune mechanisms, and visceral adiposity. These same nodal points also cause disorder that results in atrial fibrillation-related complications and the development of atrial fibrillation-associated diseases. These nodal points vary from patient to patient and can be identified by careful evaluation of the patients clinical phenotype.

SUMMARY

The application of the FMM identifies the gene--environment interactions that facilitate the patients nodal points and corrects them with emphasis on personalized diet, nutrition, and lifestyle changes.

The Role of Autoantibodies in Arrhythmogenesis

PURPOSE OF REVIEW

The role of autoantibodies in arrhythmogenesis has been the subject of research in recent times. This review focuses on the rapidly expanding field of autoantibody-mediated cardiac arrhythmias.

RECENT FINDINGS

Since the discovery of cardiac autoantibodies more than three decades ago, a great deal of effort has been devoted to understanding their contribution to arrhythmias. Different cardiac receptors and ion channels were identified as targets for autoantibodies, the binding of which either initiates a signaling cascade or serves as a biomarker of underlying remodeling process. Consequently, the wide spectrum of heart rhythm disturbances may emerge, ranging from atrial to ventricular arrhythmias as well as conduction diseases, irrespective of concomitant structural heart disease or manifest autoimmune disorder. The time has come to acknowledge autoimmune cardiac arrhythmias as a distinct disease entity. Establishing the autoantibody profile of patients will help to develop novel treatment approaches for patients.

Arrhythmias Associated with Inflammatory Cardiomyopathies

Purpose of review

To provide an approach to the diagnosis and treatment of arrhythmias associated with inflammatory cardiomyopathies.

Recent findings

Inflammatory cardiomyopathies are increasingly recognized as the etiology of both ventricular and supraventricular arrhythmias. There have been recent studies providing novel insights into the pathogenesis of arrhythmias in inflammatory cardiomyopathies and exploring the role of various diagnostic tools and treatment strategies.

Summary

Patients with inflammatory cardiomyopathies often present with one or more arrhythmias, including atrioventricular block, atrial and ventricular tachyarrhythmias, and occasionally sudden cardiac death. Given dynamic pathophysiology and heterogeneous presentation, the management of arrhythmias in these patients presents unique challenges. We review the current approach to the diagnosis and treatment of arrhythmias in this challenging cohort of patients with an emphasis on cardiac sarcoidosis.

Supplementary Information

The online version of this article (10.1007/s11936-020-00871-5) contains supplementary material, which is available to authorized users.

Baseline and Dynamic Risk Predictors of Appropriate Implantable Cardioverter Defibrillator Therapy

Background Current approaches fail to separate patients at high versus low risk for ventricular arrhythmias owing to overreliance on a snapshot left ventricular ejection fraction measure. We used statistical machine learning to identify important cardiac imaging and time-varying risk predictors. Methods and Results Three hundred eighty-two cardiomyopathy patients (left ventricular ejection fraction ≤35%) underwent cardiac magnetic resonance before primary prevention implantable cardioverter defibrillator insertion. The primary end point was appropriate implantable cardioverter defibrillator discharge or sudden death. Patient characteristics; serum biomarkers of inflammation, neurohormonal status, and injury; and cardiac magnetic resonance-measured left ventricle and left atrial indices and myocardial scar burden were assessed at baseline. Time-varying covariates comprised interval heart failure hospitalizations and left ventricular ejection fractions. A random forest statistical method for survival, longitudinal, and multivariable outcomes incorporating baseline and time-varying variables was compared with (1) Seattle Heart Failure model scores and (2) random forest survival and Cox regression models incorporating baseline characteristics with and without imaging variables. Age averaged 57±13 years with 28% women, 66% white, 51% ischemic, and follow-up time of 5.9±2.3 years. The primary end point (n=75) occurred at 3.3±2.4 years. Random forest statistical method for survival, longitudinal, and multivariable outcomes with baseline and time-varying predictors had the highest area under the receiver operating curve, median 0.88 (95% CI, 0.75-0.96). Top predictors comprised heart failure hospitalization, left ventricle scar, left ventricle and left atrial volumes, left atrial function, and interleukin-6 level; heart failure accounted for 67% of the variation explained by the prediction, imaging 27%, and interleukin-6 2%. Serial left ventricular ejection fraction was not a significant predictor. Conclusions Hospitalization for heart failure and baseline cardiac metrics substantially improve ventricular arrhythmic risk prediction.

Association between Corrected QT Interval and C-Reactive Protein in Patients with Inflammatory Bowel Diseases

Background and objectives: Electrocardiograph abnormalities (i.e., QT interval prolongation) have been described in inflammatory bowel diseases (IBD). We aimed to measure the QT interval in a cohort of patients with IBD and to analyze its relationship with clinical and inflammatory activity. Materials and Methods: We performed a cross-sectional study that included 38 IBD outpatients and 38 “age- and sex-matched” healthy controls. Nine patients had active IBD, and 29 were in clinical remission. Among the latter, 10 patients had sustained (lasting >1 year) and 19 had short-term remission (≤1 year). Corrected QT (QTc) interval was measured on standard 12-lead electrocardiograph. A systematic review of the literature on studies investigating the QT interval in patients with IBD was also performed. Results: QTc interval values were similar between IBD patients and healthy controls (417.58 ± 22.05 ms vs. 409.13 ± 19.61 ms, respectively; p: 0.479). Patients with active IBD had significantly higher QTc values (435.11 ± 27.31 ms) than both controls (409.13 ± 19.61 ms) and patients in remission (412.14 ± 17.33 ms) (p: 0.031). Post hoc analysis showed that the difference in QTc values between active IBD and remission was attributable to the group of patients with sustained remission (p < 0.05). Lastly, a significant correlation between QTc interval and C-reactive protein (CRP) values was observed (Spearman test: r = 0.563; p: 0.0005). Conclusions: Our study demonstrates an association between QTc duration and both clinical and inflammatory activity in patients with IBD. The higher the CRP value, the longer is the QTc duration. For practical purposes, all patients with active IBD should undergo a standard ECG. Prescription of drugs able to modify the QT interval should be avoided in patients with active IBD. The systematic review of the literature indicated that this is the first published study demonstrating an association between the QTc duration and CRP values in patients with IBD.

A Broader Perspective on Anti-Ro Antibodies and Their Fetal Consequences-A Case Report and Literature Review

The presence of maternal Anti-Ro/Anti-La antibodies causes a passively acquired autoimmunity that may be associated with serious fetal complications. The classic example is the autoimmune-mediated congenital heart block (CHB) which is due in most cases to the transplacental passage of Anti-Ro/Anti-La antibodies. The exact mechanisms through which these pathologic events arise are linked to disturbances in calcium channels function, impairment of calcium homeostasis and ultimately apoptosis, inflammation and fibrosis. CHB still represents a challenging diagnosis and a source of debate regarding the best management. As the third-degree block is usually irreversible, the best strategy is risk awareness and prevention. Although CHB is a rare occurrence, it affects one in 20,000 live births, with a high overall mortality rate (up to 20%, with 70% of in utero deaths). There is also concern over the lifelong consequences, as most babies need a pacemaker. This review aims to offer, apart from the data needed for a better understanding of the issue at hand, a broader perspective of the specialists directly involved in managing this pathology: the rheumatologist, the maternal-fetal specialist and the cardiologist. To better illustrate the theoretical facts presented, we also include a representative clinical case.

Cardiac Arrest Risk During Acute Infections: Systemic Inflammation Directly Prolongs QTc Interval via Cytokine-Mediated Effects on Potassium Channel Expression

BACKGROUND

During acute infections, the risk of malignant ventricular arrhythmias is increased, partly because of a higher propensity to develop QTc prolongation. Although it is generally believed that QTc changes almost exclusively result from concomitant treatment with QT-prolonging antimicrobials, direct effects of inflammatory cytokines on ventricular repolarization are increasingly recognized. We hypothesized that systemic inflammation per se can significantly prolong QTc during acute infections, via cytokine-mediated changes in K⁺ channel expression.

METHODS

We evaluated (1) the frequency of QTc prolongation and its association with inflammatory markers, in patients with different types of acute infections, during active disease and remission; (2) the prevalence of acute infections in a cohort of consecutive patients with Torsades de Pointes; (3) the relationship between K⁺ channel mRNA levels in ventricles and peripheral blood mononuclear cells and their changes in patients with acute infection over time.

RESULTS

In patients with acute infections, regardless of concomitant QT-prolonging antimicrobial treatments, QTc was significantly prolonged but rapidly normalized in parallel to CRP (C-reactive protein) and cytokine level reduction. Consistently in the Torsades de Pointes cohort, concomitant acute infections were highly prevalent (30%), despite only a minority (25%) of these cases were treated with QT-prolonging antimicrobials. KCNJ2 K⁺ channel expression in peripheral blood mononuclear cell, which strongly correlated to that in ventricles, inversely associated to CRP and IL (interleukin)-1 changes in acute infection patients.

CONCLUSIONS

During acute infections, systemic inflammation rapidly induces cytokine-mediated ventricular electrical remodeling and significant QTc prolongation, regardless concomitant antimicrobial therapy. Although transient, these changes may significantly increase the risk of life-threatening ventricular arrhythmia in these patients. It is timely and warranted to transpose these findings to the current coronavirus disease 2019 (COVID-19) pandemic, in which both increased amounts of circulating cytokines and cardiac arrhythmias are demonstrated along with a frequent concomitant treatment with several QT-prolonging drugs. Graphic Abstract: A graphic abstract is available for this article.