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

Autoimmune cardiac channelopathies and heart rhythm disorders: A contemporary review

Cardiac arrhythmias still represent a major health problem worldwide, at least in part because the fundamental pathogenic mechanisms are not fully understood, thus affecting the efficacy of therapeutic measures. In fact, whereas cardiac arrhythmias are in most cases due to structural heart diseases, the underlying cause remains elusive in a significant number of patients despite intensive investigations even including postmortem examination and molecular autopsy. A large body of data progressively accumulated during the last decade provides strong evidence that autoimmune mechanisms may be involved in a significant number of such unexplained or poorly explained cardiac arrhythmias. Several proarrhythmic anti-cardiac ion channel autoantibodies have been discovered, in all cases able to directly interfere with the electrophysiologic properties of the heart but leading to different arrhythmic phenotypes, including long QT syndrome, short QT syndrome, and atrioventricular block. These autoantibodies, which may develop independent of a history of autoimmune diseases, could help explain a percentage of arrhythmic events of unknown origin, thereby opening new frontiers for diagnosis and treatment of heart rhythm disorders. Based on this evidence, the novel term autoimmune cardiac channelopathies was coined in 2017. Since then, the interest in the field of cardioimmunology has shown a tumultuous growth, so much so that the number of arrhythmogenic anti-ion channel autoantibodies reported has significantly increased, also in association with not previously described arrhythmic phenotypes, such as atrial fibrillation, Brugada syndrome, and ventricular fibrillation/cardiac arrest. Thus, an updated reassessment of this topic, also highlighting perspectives and unmet needs, has become necessary and represents the main objective of this review.

Association of Electrocardiographic Patterns After Successfully Resuscitated Out-of-Hospital Cardiac Arrest With Significant Coronary Lesions and Mortality-A Predefined Angiography After Out-of-Hospital Cardiac Arrest Without ST-Segment Elevation (TOMAHAWK) Trial

OBJECTIVES

The use of electrocardiograms for predicting significant coronary lesions and mortality in patients with successfully resuscitated out-of-hospital cardiac arrest (OHCA) without ST-segment elevation has not been defined yet. The objective of this study was to investigate the association and predictive value of various standardized 12-lead electrocardiogram patterns in patients with successfully resuscitated OHCA and no ST-segment elevations on the presence of significant coronary lesions (diagnostic performance) and 30-day mortality (prognostic performance).

DESIGN

Predefined subanalysis of the Angiography after Out-of-Hospital Cardiac Arrest without ST-Segment Elevation (TOMAHAWK) trial.

SETTING

Multicenter, international randomized controlled trial across 31 centers.

PATIENTS

Adult patients with successfully resuscitated OHCA and no ST-segment elevations.

INTERVENTIONS

The first recorded electrocardiogram after the return of spontaneous circulation (ROSC) at hospital admission was analyzed by experienced physicians.

MEASUREMENTS AND MAIN RESULTS

Significant coronary lesions and 30-day mortality. In total, 412 patients with a coronary angiography were included, of which 163 (40%) had significant coronary lesions. No electrocardiogram pattern was identified as a predictor of significant coronary lesions. In the total cohort of patients with and without coronary angiography, right bundle branch blocks (BBBs), prolonged intrinsicoid deflection times, and intrinsicoid deflections in right BBB were strong, independent predictors of 30-day mortality. The "intrinsicoid deflection" is the sharp upward deflection in the QRS complex of an electrocardiogram. The "intrinsicoid deflection time" is the interval from the start of the QRS complex to the peak of the R wave. The predictive performance for significant coronary lesions was poor across all electrocardiogram patterns and better for 30-day mortality.

CONCLUSIONS

Standardized 12-lead electrocardiogram patterns after ROSC at hospital admission in patients with successfully resuscitated OHCA without ST-segment elevations have poor predictive performance for the presence of significant coronary lesions. Different QRS-related patterns might identify patients with higher risk of short-term mortality.

Does COVID-19 impact the QT interval prolongation? Answers from genetic causal inference

During the COVID-19 pandemic, there has been heightened interest in the QT interval, a crucial indicator of ventricular electrical activity. Mendelian randomization (MR) is used here to investigate the genetic causation between QT interval alterations and COVID-19. Genetic proxies representing three COVID-19 phenotypes-severe, hospitalized, and COVID-19-were identified in over 1,000,000 individuals of European ancestry. Univariate two-sample MR (TSMR) and multi-exposure-adjusted multivariate MR (MVMR) were used to assess genetic causal associations between COVID-19 and QT intervals in 84,630 UK Biobank participants. The MR-robust adjusted profile score (MR-RAPS) method and radial MR frame were utilized for effective robustness and outlier variant detection, with sensitivity analyses conducted to identify horizontal pleiotropy. For every COVID-19 phenotype, univariate TSMR analysis revealed non-significant causal estimates between COVID-19 and the QT interval [COVID-19: βIVW (95% CI): -0.44 (-1.72, 0.84), P = 0.50; hospitalization: βIVW: 0.12 (-0.57, 0.80), P = 0.74; severe case: βIVW: 0.11 (-0.29, 0.51), P = 0.58]. MR-RAPS and outlier-corrected radial MR analyses further supported this null causal estimation. In confounder-adjusted MVMR analysis, this nonsignificant causality was independent of body mass index (BMI), smoking, and alcohol consumption [βBMI+Alcohol+Smoking (95% CI): -0.77 (-2.44, 0.91), P = 0.37]. Sensitivity analyses did not detect any evidence of bias from horizontal pleiotropy, abnormal data distribution, or weak instruments. These findings suggest that COVID-19 does not directly causally prolong the QT interval. Inconsistent findings in observational research may be attributed to residual confounding.

Metabolic acidosis and sudden infant death syndrome: overlooked data provides insight into SIDS pathogenesis

BACKGROUND

Decades of mainstream SIDS research based on the Triple Risk Model and neuropathological findings have failed to provide convincing evidence for a primary CNS-based mechanism behind putative secondary dyshomeostasis (respiratory or cardiac) or impaired arousal. Newly revealed data indicate that severe metabolic acidosis (and severe hyperkalemia) is a common accompaniment in SIDS. This supports the direct effect of sepsis on vital-organ function and occurrence of secondary CNS changes accompanied by the dyshomeostasis leading to SIDS.

DATA SOURCES

Using PubMed and Google Scholar literature searches, this paper examines how metabolic acidosis and sepsis might contribute to the underlying pathophysiologic mechanisms in SIDS.

RESULTS

The discovery of a series of non-peer-reviewed publications provided the basis for a serious examination of the role of metabolic acidosis and sepsis in SIDS. Most SIDS risk factors relate directly or indirectly to infection. This consequently elevated the position of septic or superantigenic shock and viremia in causing secondary organ failure leading to SIDS. The latter could include diaphragmatic failure, as evidenced by peripheral respiratory (muscle) arrests in experimental septic shock, as well as infectious myositis and diaphragm myopathy in sudden unexpected deaths, including SIDS. In addition, just as acidosis lowers the threshold for ventricular fibrillation and sudden cardiac arrest, it could also contribute to similarly unstable diaphragm excitation states leading to respiratory failure.

CONCLUSIONS

This paper uniquely reveals compelling evidence for a connection between metabolic acidosis, sepsis, viral infections, and sudden unexpected child deaths and provides a solid basis for further work to define which pathway (or pathways) lead to the tragedy of SIDS. It is recommended that all autopsies in sudden unexpected deaths should include pH, bicarbonate, lactate, and electrolyte measurements, as well as diaphragm histology.

Evaluation of ventricular repolarization in dermatomyositis and relationship with inflammation and autoimmunity

Dermatomyositis (DM) is a chronic multi-systemic inflammatory disorder of autoimmune origin, which has been associated with cardiovascular complications, including ventricular arrhythmias and sudden cardiac death. The Tp-e interval and Tp-e/QT ratio have been accepted as new markers for the assessment of myocardial repolarization and ventricular arrhythmogenesis. The aim of this study was to evaluate ventricular repolarization by using Tp-e interval and Tp-e/QT ratio in patients with DM, and to assess the relation with inflammation and autoimmunity. This study included 281 DM patients (180 females, 101 males; mean age 52.73 ± 15.80 years) and 281 control subjects (180 females, 101 males; mean age 53.38 ± 15.72 years). QTc, Tp-e interval and Tp-e/QT ratio were measured from the 12-lead ECG. The plasma level of blood routine test, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) was measured. These parameters were compared between groups. No statistically significant difference was found between two groups in terms of basic characteristics. In electrocardiographic parameters analysis, QTc, Tp-e interval and Tp-e/QT ratio were significantly increased in DM patients compared to the control group (441.44 ± 26.62 ms vs 422.72 ± 11.7 ms, 104.16 ± 24.34 ms vs 77.23 ± 16.25 ms and 0.27 ± 0.06 ms vs 0.20 ± 0.04 ms, all P value < 0.01). QTc, Tp-e interval and Tp-e/QT were positively correlated with NLR, CRP, and ESR (all P values < 0.01), and were increased in anti-Ro/SSA-52kD positive patients compared to those negative (452.33 ± 24.89 ms vs 438.55 ± 26.37 ms, 114.05 ± 22.68 ms vs 101.53 ± 24.13 ms, and 0.29 ± 0.06 ms vs 0.27 ± 0.05 ms, all P value < 0.01). Our study demonstrated that QTc, Tp-e interval, and Tp-e/QT ratio were increased in DM patients and were associated with inflammatory markers and anti-Ro/SSA-52kD positivity.

Impact of preoperative QTc interval prolongation on short-term postoperative outcomes: A retrospective study

STUDY OBJECTIVE

Although a prolonged heart rate-corrected QT interval (QTcI) is associated with an increased risk of mortality in the general population, its prognostic value in surgical patients remains unclear. We aimed to examine whether preoperative QTcI prolongation predicts short-term postoperative outcomes in elderly patients undergoing noncardiac surgery.

DESIGN

The study was a retrospective analysis using the TriNetX network database.

SETTING

Operating room.

INTERVENTION

Assessment and categorization of preoperative QTcI.

PATIENTS

Data of patients aged ≥65 years who underwent non-cardiac surgery between 2010 and 2023 were analyzed.

MEASUREMENTS

Patients were categorized into four groups based on preoperative QTcI: long (500-600 ms), borderline (460-500 ms), high-normal (420-460 ms) and control (370-420 ms) groups. The groups were compared using a propensity score-matched analysis. The primary outcome was the all-cause 90-day mortality risk. The secondary outcomes included 90-day risks of postoperative new-onset atrial fibrillation (Af), ventricular arrhythmias (VAs), emergency visits, hospital readmissions, and pneumonia.

RESULTS

In total, data on 519,929 patients were collected in this study. Pairwise comparisons showed that all QTcI prolongation groups demonstrated a heightened incidence of postoperative mortality, arrhythmias, and other complications compared to the control group. Patients with a long QTcI had a 3-fold higher risk of mortality (hazard ratio [HR] = 3.124, p < 0.001), Af (HR = 3.059, p < 0.001), and VAs (HR = 3.617, p < 0.001) than controls. The risks of emergency visits (HR = 1.287, p < 0.001), hospital readmissions (HR = 1.591, p < 0.001), and pneumonia (HR = 1.672, p < 0.001) were also higher in the long QTcI group than in the control group. A dose-dependent response was evident between QTcI and mortality as well as arrhythmia risk.

CONCLUSION

Preoperative QTcI screening effectively risk-stratifies elderly surgical patients, with a QTcI≥500 ms being strongly predictive of short-term postoperative mortality and other complications. Incorporating QTcI assessment into the preoperative evaluation may guide perioperative monitoring and management.

Prevalence, Outcomes, and Predictors of Prolonged Corrected QT Interval in Hydroxychloroquine-Naïve Hospitalized COVID-19 Patients

The studies regarding prevalence, outcomes, and predictors of prolonged corrected QT (QTc) among COVID-19 patients not on QTc-prolonging medication are not available in the literature. In this retrospective cohort study, the QTc of 295 hospital-admitted COVID-19 patients was analyzed and its association with in-hospital mortality was determined. The QTc was prolonged in 14.6% (43/295) of the study population. Prolonged QTc was seen in patients with older age (P = 0.018), coronary artery disease (P = 0.001), congestive heart failure (P = 0.042), elevated N-terminal-pro-B-type natriuretic peptide (NT-ProBNP) (P < 0.0001), and on remdesivir (P = 0.046). No episode of torsades de pointes arrhythmia or any arrhythmic death was observed among patients with prolonged QTc. The mortality was significantly high in patients with prolonged QTc (P = 0.003). The multivariate logistic regression analysis showed coronary artery disease (odds ratio (OR): 4.153, 95% CI 1.37-14.86; P = 0.013), and NT-ProBNP (ng/L) (OR: 1.000, 95% CI 1.000-1.000; P = 0.007) as predictors of prolonged QTc. The prolonged QTc was associated with the worst in-hospital survival (p by log-rank 0.001). A significant independent association was observed between prolonged QTc and in-hospital mortality in multivariate cox-regression analysis (adjusted hazard ratio: 3.861; (95% CI 1.719-6.523), P < 0.0001). QTc was found to be a marker of underlying comorbidities among COVID-19 patients. Prolonged QTc in hospitalized COVID-19 patients was independently associated with in-hospital mortality.

Cardiac arrhythmia in COVID-19 patients

The coronavirus disease 2019 (COVID-19) was first introduced in December 2019, which is known as severe acute respiratory syndrome caused by coronavirus-2 (SARS-CoV-2) that is a serious and life-threatening disease. Although pneumonia is the most common manifestation of COVID-19 and was initially introduced as a respiratory infection, in fact, the infection of COVID-19 is a subset of complications and damage to various organs. There are several reports of cardiac involvement with COVID-19. A wide range of cardiac complications may occur following COVID-19 infection, including systolic heart failure, myocarditis, pericarditis, atrial and ventricular arrhythmias, and thromboembolic events. There are various hypotheses about the pathophysiology of cardiovascular involvement by this virus. At the top of these hypotheses is the release of cytokines to the heart. Although there are other assumptions, considering that one of the causes of death in patients with COVID-19 is arrhythmia. It is necessary to know correctly about its pathophysiology and etiology. Therefore, in this study, we have reviewed the articles of recent years in the field of pathophysiology and etiology of arrhythmia in patients with COVID-19 infection. The purpose of this study was to provide a basis for a correct and more comprehensive understanding of the pathogenesis of arrhythmia in patients with COVID-19 infection.

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.

QTc Prolongation to Predict Mortality in Patients Admitted with COVID-19 Infection: An Observational Study

BACKGROUND

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes Coronavirus disease 2019 (COVID-19), characterized by pulmonary infection ranging from asymptomatic forms to respiratory insufficiency and death. Evidence of cardiac involvement in COVID-19 is increasing, and systemic inflammation or direct heart damage by SARS-CoV-2 can prolong the corrected QT interval (QTc).

METHODS

In this observational study, a total of 333 consecutive patients admitted to the Covid Center of Verona University Hospital from November 2020 to April 2021 were included. Patients with bundle branch block, pacemaker-controlled heart rhythm and heart rate >120 beats/min were excluded. A complete electrocardiogram (ECG) was performed at admission, and QTc values of ≥440 ms for males and ≥460 ms for females were considered prolonged.

RESULTS

Overall, 153 patients had prolonged QTc (45.5%). In multivariate logistic regression analysis, male sex (odds ratio (OR)=6.612, p=0.046), troponin (OR=1.04, p=0.015) and lymphocyte count (OR=3.047, p=0.019) were independently associated with QTc prolongation. Multivariate logistic regression showed that QTc was independently associated with mortality (OR=4.598, p=0.036). Age, sex, the ratio between the partial pressure of oxygen (PaO2) and the fraction of inspired oxygen (FiO2) (P/F), and fibrosis-4 index for liver fibrosis (FIB-4) were also independently associated with mortality.

CONCLUSION

QTc interval prolongation appears to be a frequent finding in patients with COVID-19. Moreover, prolonged QTc may be predictive of more severe forms of COVID-19 and worse outcome.

Extensive longitudinal acute transverse myelitis complicated by pulseless ventricular tachycardia and recent shingles vaccination

This case describes a 50-year-old male with a history of psoriatic arthritis who presented to the emergency department with a chief complaint of ascending bilateral lower extremity paresthesia one week following a shingles vaccine. MRI of the patient's spine was significant for longitudinally extensive T2 hyperintensity involving the lower cervical spine with extension into the upper thoracic spine suggestive of acute transverse myelitis (ATM). The patient's hospital course was complicated by a self-limiting episode of pulseless ventricular tachycardia accompanied by a brief loss of consciousness. Initial treatment included IV solumedrol, however due to lack of clinical improvement after a 5-day steroid treatment, plasmapheresis was initiated. The patient's condition improved with plasmapheresis and he was subsequently discharged to a rehab facility with a diagnosis of ATM of unclear etiology. Extensive serology, cardiac and CSF studies failed to determine the cause of this patient's myelitis or pulseless ventricular tachycardia. The following case report explores the potential factors that may have contributed to this patient's symptoms.

The natural history of QTc interval and its clinical impact in coronavirus disease 2019 survivors after 1 year

Background and objective

Prolonged QTc interval on admission and a higher risk of death in SARS-CoV-2 patients have been reported. The long-term clinical impact of prolonged QTc interval is unknown. This study examined the relationship in COVID-19 survivors of a prolonged QTc on admission with long-term adverse events, changes in QTc duration and its impact on 1-year prognosis, and factors associated with a prolonged QTc at follow-up.

Methods

We conducted a single-center prospective cohort study of 523 SARS-CoV-2-positive patients who were alive on discharge. An electrocardiogram was taken on these patients within the first 48 h after diagnosis and before the administration of any medication with a known effect on QT interval and repeated in 421 patients 7 months after discharge. Mortality, hospital readmission, and new arrhythmia rates 1 year after discharge were reviewed.

Results

Thirty-one (6.3%) survivors had a baseline prolonged QTc. They were older, had more cardiovascular risk factors, cardiac disease, and comorbidities, and higher levels of terminal pro-brain natriuretic peptide. There was no relationship between prolonged QTc on admission and the 1-year endpoint (9.8% vs. 5.5%, p = 0.212). In 84% of survivors with prolonged baseline QTc, it normalized at 7.9 ± 2.2 months. Of the survivors, 2.4% had prolonged QTc at follow-up, and this was independently associated with obesity, ischemic cardiomyopathy, chronic obstructive pulmonary disease, and cancer. Prolonged baseline QTc was not independently associated with the composite adverse event at 1 year.

Conclusions

Prolonged QTc in the acute phase normalized in most COVID-19 survivors and had no clinical long-term impact. Prolonged QTc at follow-up was related to the presence of obesity and previously acquired chronic diseases and was not related to 1-year prognosis.

Evolution and triggers of defibrillator shocks in patients with arrhythmogenic right ventricular cardiomyopathy

INTRODUCTION

Implantable cardioverter-defibrillators (ICDs) can prevent sudden cardiac death due to ventricular arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). The aim of our study was to assess the cumulative burden, evolution and potential triggers of appropriate ICD shocks during long-term follow-up, which may help to reduce and further refine individual arrhythmic risk in this challenging disease.

METHODS

This retrospective cohort study included 53 patients with definite ARVC according to the 2010 Task Force Criteria from the multicentre Swiss ARVC Registry with an implanted ICD for primary or secondary prevention. Follow-up was conducted by assessing all available patient records from patient visits, hospitalisations, blood samples, genetic analysis, as well as device interrogation and tracings.

RESULTS

Fifty-three patients (male 71.7%, mean age 43±2.2 years, genotype positive 58.5%) were analysed during a median follow-up of 7.9 (IQR 10) years. In 29 (54.7%) patients, 177 appropriate ICD shocks associated with 71 shock episodes occurred. Median time to first appropriate ICD shock was 2.8 (IQR 3.6) years. Long-term risk of shocks remained high throughout long-term follow-up. Shock episodes occurred mainly during daytime (91.5%, n=65) and without seasonal preference. We identified potentially reversible triggers in 56 of 71 (78.9%) appropriate shock episodes, the main triggers representing physical activity, inflammation and hypokalaemia.

CONCLUSION

The long-term risk of appropriate ICD shocks in patients with ARVC remains high during long-term follow-up. Ventricular arrhythmias occur more often during daytime, without seasonal preference. Reversible triggers are frequent with the most common triggers for appropriate ICD shocks being physical activity, inflammation and hypokalaemia in this patient population.

C-L Case Conference: Torsades de Pointes in a Patient With Lifelong Medical Trauma, COVID-19, Remdesivir, Citalopram, Quetiapine, and Hemodialysis

We present a case of Torsades de Pointes (TdP) in a patient with COVID-19 infection and multiple TdP risk factors including QT-interval prolongation, hemodialysis, bradycardia, and treatment with remdesivir, citalopram, and quetiapine. The case was complicated by post-resuscitation anxiety superimposed on a history of medical trauma since childhood. Top experts in the field of consultation-liaison psychiatry, trauma informed care, and cardiac electrophysiology provide perspectives on this case with a review of the literature. Key teaching topics include identification of TdP risk factors in patients with a complex illness; the necessity for prompt electrophysiology consultation in clinical scenarios with high risk for TdP; and the approach to patients with medical trauma using a trauma-informed lens. We highlight the contributions of COVID-19, the pharmacokinetics of QT-interval-prolonging psychotropic medications, the risks of hemodialysis, and the role of remdesivir-induced bradycardia in this first reported case of TdP in a patient treated with remdesivir.

Effects of COVID-19 on Arrhythmia

The World Health Organization announced that COVID-19, with SARS-CoV-2 as its pathogen, had become a pandemic on 11 March 2020. Today, the global epidemic situation is still serious. With the development of research, cardiovascular injury in patients with COVID-19, such as arrhythmia, myocardial injury, and heart failure, is the second major symptom in addition to respiratory symptoms, and cardiovascular injury is related to the prognosis and mortality of patients. The incidence of arrhythmia in COVID-19 patients ranges from 10% to 20%. The potential mechanisms include viral infection-induced angiotensin-converting enzyme 2 expression change, myocarditis, cytokine storm, cardiac injury, electrophysiological effects, hypoxemia, myocardial strain, electrolyte abnormalities, intravascular volume imbalance, drug toxicities and interactions, and stress response caused by virus infection. COVID-19 complicated with arrhythmia needs to be accounted for and integrated in management. This article reviews the incidence, potential mechanisms, and related management measures of arrhythmia in COVID-19 patients.

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.

C-reactive Protein Elevation Is Associated With QTc Interval Prolongation in Patients Hospitalized With COVID-19

Background

The relationship between inflammation and corrected QT (QTc) interval prolongation is currently not well defined in patients with COVID-19.

Objective

This study aimed to assess the effect of marked interval changes in the inflammatory marker C-reactive protein (CRP) on QTc interval in patients hospitalized with COVID-19.

Methods

In this retrospective cohort study of hospitalized adult patients admitted with COVID-19 infection, we identified 85 patients who had markedly elevated CRP levels and serial measurements of an ECG and CRP during the same admission. We compared mean QTc interval duration, and other clinical and ECG characteristics between times when CRP values were high and low. We performed mixed-effects linear regression analysis to identify associations between CRP levels and QTc interval in univariable and adjusted models.

Results

Mean age was 58 ± 16 years, of which 39% were women, 41% were Black, and 25% were White. On average, the QTc interval calculated via the Bazett formula was 15 ms higher when the CRP values were “high” vs. “low” [447 ms (IQR 427–472 ms) and 432 ms (IQR 412–452 ms), respectively]. A 100 mg/L increase in CRP was associated with a 1.5 ms increase in QTc interval [β coefficient 0.15, 95% CI (0.06–0.24). In a fully adjusted model for sociodemographic, ECG, and clinical factors, the association remained significant (β coefficient 0.14, 95% CI 0.05–0.23).

Conclusion

An interval QTc interval prolongation is observed with a marked elevation in CRP levels in patients with COVID-19.

Incidence and Predictors of Cardiac Arrhythmias in Patients With COVID-19

Background

Coronavirus disease 2019 (COVID-19) is a systemic disease caused by severe acute respiratory syndrome coronavirus 2. Arrhythmias are frequently associated with COVID-19 and could be the result of inflammation or hypoxia. This study aimed to define the incidence of arrhythmias in patients with COVID-19 and to correlate arrhythmias with pulmonary damage assessed by computed tomography (CT).

Methods

All consecutive patients with a COVID-19 diagnosis hospitalized at Universitair Ziekenhuis Brussel, Belgium, between March 2020 and May 2020, were screened. All included patients underwent a thorax CT scan and a CT severity score, a semiquantitative scoring system of pulmonary damage, was calculated. The primary endpoint was the arrhythmia occurrence during follow-up.

Results

In this study, 100 patients were prospectively included. At a mean follow-up of 19.6 months, 25 patients with COVID-19 (25%) experienced 26 arrhythmic episodes, including atrial fibrillation in 17 patients, inappropriate sinus tachycardia in 7 patients, atrial flutter in 1 patient, and third-degree atrioventricular block in 1 patient. No ventricular arrhythmias were documented. Patients with COVID-19 with arrhythmias showed more often need for oxygen, higher oxygen maximum flow, longer QTc at admission, and worse damage at CT severity score. In univariate logistic regression analysis, significant predictors of the primary endpoint were: the need for oxygen therapy (odds ratio [OR] 4.59, 95% CI 1.44-14.67, p = 0.01) and CT severity score of pulmonary damage (OR per 1 point increase 1.25, 95% CI 1.11-1.4, p < 0.001).

Conclusions

In a consecutive cohort of patients with COVID-19 the incidence of cardiac arrhythmias was 25%. The need for oxygen therapy and CT severity score were predictors of arrhythmia occurrence during follow-up.

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.

Bacterial etiology and mortality rate in community-acquired pneumonia, healthcare-associated pneumonia and hospital-acquired pneumonia in Thai university hospital

Pneumonia is caused by infection at the pulmonary parenchyma which constitutes a crucial risk factor for morbidity and mortality. We aimed to determine the mortality rate and its risk factors as well as etiology among inpatients with community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP) and healthcare-associated pneumonia (HCAP). A hospital-based retrospective cohort study was conducted in a university hospital located in Bangkok, Thailand. A total of 250 inpatients with pneumonia was included in the present study. The inhospital mortality rate was 1.25 (95% CI 0.99-1.56) per 100 person-days. The present study reported that overall pneumonia caused by gram-negative pathogens accounted for 60.5%. P. aeruginosa was a frequent gram-negative pathogen among these participants, especially among patients with HCAP and HAP. Adjusted hazard ratio (AHR) of inhospital mortality among patients with HAP was 1.75 (95% CI 1.01-3.03) times that of those among patients with CAP, while AHR for 28-day mortality among patients with HAP compared with those with CAP was 2.81 (95% CI 1.38-5.75). Individual risks factors including cardiomyopathy, active-smoker and insulin use were potential risk factors for mortality. Initial qSOFA and acid-based disturbance should be assessed to improve proper management and outcomes.

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.

Neutrophil-to-Lymphocyte Ratio (NLR) Is a Promising Predictor of Mortality and Admission to Intensive Care Unit of COVID-19 Patients

The neutrophil-to-lymphocyte ratio (NLR) is an inflammatory marker predicting the prognosis of several diseases. We aimed to assess its role as a predictor of mortality or admission to the intensive care unit in COVID-19 patients. We retrospectively evaluated a cohort of 411 patients with COVID-19 infection. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and C-reactive protein (CRP) of patients with COVID-19 were compared. The median age of our sample was 72 years (interquartile range: 70−75); 237 were males. Hypertension, diabetes and ischemic heart disease were the most common comorbidities. The study population was subdivided into three groups according to NLR tertiles. Third-tertile patients were older, showing significantly higher levels of inflammatory markers; 133 patients (32%) died during hospitalization, 81 of whom belonged to the third tertile; 79 patients (19%) were admitted to ICU. NLR showed the largest area under the curve (0.772), with the highest specificity (71.9%) and sensitivity (72.9%), whereas CRP showed lower sensitivity (60.2%) but slightly higher specificity (72.3%). Comparisons between NLR and CRP ROC curves were significantly different (p = 0.0173). Cox regression models showed that the association between NLR and death was not weakened after adjustment for confounders. Comparisons of ROC curves showed no significant differences between NLR, PLR, and CRP. Cox regression analysis showed that NLR predicted the risk of admission to ICU independently of demographic characteristics and comorbidities (HR: 3.9597, p < 0.0001). These findings provide evidence that NLR is an independent predictor of mortality and a worse outcome in COVID-19 patients and may help identify high-risk individuals with COVID-19 infection at admission.

Alpha1-adrenoceptors activate NLRP3 inflammasome through downregulation of Kir2.1 in cardiac inflammation

NEW FINDINGS

What is the central question of this study? The mechanism of cardiac inflammation induced by α ₁ -AR stimulation by NLRP3 inflammasome activation is unclear. What is the main finding and its importance? In the mechanism of cardiac inflammation induced by α₁ -AR overreaction, Kir2.1 exerts cardioprotective and anti-inflammatory effects by inhibiting the activation of NLRP3 Inflammasome.

ABSTRACT

Overstimulated sympathetic nerves in cardiovascular diseases can lead to impaired cardiomyocyte function and potential heart failure, which activates not only β-AR but also α₁ -AR. A previous report indicated that NLRP3 inflammasome activation is involved in cardiac inflammation induced by the α₁ -AR agonist phenylephrine, but the mechanism is still unknown. Here, we aimed to study whether Kir2.1 is involved in cardiac inflammation caused by phenylephrine. The results from in vitro experiments showed that phenylephrine upregulated the expression levels of NLRP3, Caspase-1, IL-18, and IL-1β and downregulated the expression level of Kir2.1 in H9C2 cells. The Kir2.1 agonist zacopride downregulated the expression of NLRP3, Caspase-1, IL-1β and IL-18, and the Kir2.1 inhibitor ML133 upregulated the expression of these genes. To further explore the mechanism, we found that zacopride downregulated the protein expression level of p-p65 and that ML133 upregulated it. Moreover, the NF-κB signaling pathway inhibitor curcumenol reversed the expression of NLRP3 inflammasomes caused by phenylephrine in H9C2 cells. In vivo experiments, the protein expression level of Kir2.1 in the phenylephrine group was significantly decreased, and the activation of Kir2.1 by zacopride reduced cardiac inflammation. In short, Kir2.1 is related to α₁ -AR overactivation, which induces cardiac inflammation, through the NF-κB signaling pathway, and activating Kir2.1 can downregulate NLRP3 inflammation and exert cardioprotective effects by zacopride. This article is protected by copyright. All rights reserved.

QTc interval prolongation, inflammation, and mortality in patients with COVID-19

PURPOSE

Systemic inflammation has been associated with corrected QT (QTc) interval prolongation. The role of inflammation on QTc prolongation in COVID-19 patients was investigated.

METHODS

Patients with a laboratory-confirmed SARS-CoV-2 infection admitted to IRCCS San Raffaele Scientific Institute (Milan, Italy) between March 14, 2020, and March 30, 2020 were included. QTc-I was defined as the QTc interval by Bazett formula in the first ECG performed during the hospitalization, before any new drug treatment; QTc-II was the QTc in the ECG performed after the initiation of hydroxychloroquine drug treatment.

RESULTS

QTc-I was long in 45 patients (45%) and normal in 55 patients (55%). Patients with long QTc-I were older and more frequently males. C-Reactive protein (CRP) and white blood cell (WBC) count at hospitalization were higher in patients with long QTc-I and long QTc-II. QTc-I was significantly correlated with CRP levels at hospitalization. After a median follow-up of 83 days, 14 patients (14%) died. There were no deaths attributed to ventricular arrhythmias. Patients with long QTc-I and long QTc-II had a shorter survival, compared with normal QTc-I and QTc-II patients, respectively. In Cox multivariate analysis, independent predictors of mortality were age (HR = 1.1, CI 95% 1.04-1.18, p = 0.002) and CRP at ECG II (HR 1.1, CI 95% 1.0-1.1, p = 0.02).

CONCLUSIONS

QTc at hospitalization is a simple risk marker of mortality risk in COVID-19 patients and reflects the myocardial inflammatory status.

Sex-Specific Cardiovascular Risks of Cancer and Its Therapies

In both cardiovascular disease and cancer, there are established sex-based differences in prevalence and outcomes. Males and females may also differ in terms of risk of cardiotoxicity following cancer therapy, including heart failure, cardiomyopathy, atherosclerosis, thromboembolism, arrhythmias, and myocarditis. Here, we describe sex-based differences in the epidemiology and pathophysiology of cardiotoxicity associated with anthracyclines, hematopoietic stem cell transplant (HCT), hormone therapy and immune therapy. Relative to males, the risk of anthracycline-induced cardiotoxicity is higher in prepubertal females, lower in premenopausal females, and similar in postmenopausal females. For autologous hematopoietic cell transplant, several studies suggest an increased risk of late heart failure in female lymphoma patients, but sex-based differences have not been shown for allogeneic hematopoietic cell transplant. Hormone therapies including GnRH (gonadotropin-releasing hormone) modulators, androgen receptor antagonists, selective estrogen receptor modulators, and aromatase inhibitors are associated with cardiotoxicity, including arrhythmia and venous thromboembolism. However, sex-based differences have not yet been elucidated. Evaluation of sex differences in cardiotoxicity related to immune therapy is limited, in part, due to low participation of females in relevant clinical trials. However, some studies suggest that females are at increased risk of immune checkpoint inhibitor myocarditis, although this has not been consistently demonstrated. For each of the aforementioned cancer therapies, we consider sex-based differences according to cardiotoxicity management. We identify knowledge gaps to guide future mechanistic and prospective clinical studies. Furthering our understanding of sex-based differences in cancer therapy cardiotoxicity can advance the development of targeted preventive and therapeutic cardioprotective strategies.

Effects of azithromycin on ventricular repolarization in children with COVID-19

Introduction

Azithromycin is used to treat pediatric COVID-19 patients. It can also prolong the QT interval in adults. This study assessed the effects of azithromycin on ventricular repolarization in children with COVID-19.

Method

The study prospectively enrolled children with COVID-19 who received azithromycin between July and August 2020. An electrocardiogram was performed before, one, three, and five days post-treatment. Using ImageJ®, the following parameters were measured: QT max, QT min, Tp-e max, and Tp-e min. The parameters QTc max, QTc min, Tp-ec max, Tp-ec min, QTcd, Tp-ecd, and the QTc/Tp-ec ratio were calculated using Bazett's formula.

Results

The study included 105 pediatric patients (mean age 9.8±5.3 years). The pretreatment heart rate was higher than after treatment (before 92 [79–108]/min vs. Day 1 82 [69–108)]/min vs. Day 3 80 [68–92.2]/min vs. Day 5 81 [70–92]/min; p=0.05).

Conclusion

Azithromycin does not affect the ventricular repolarization parameters on ECG in pediatric COVID-19 cases.

Thrombocytopenia in COVID‑19 and vaccine‑induced thrombotic thrombocytopenia

The highly heterogeneous symptomatology and unpredictable progress of COVID-19 triggered unprecedented intensive biomedical research and a number of clinical research projects. Although the pathophysiology of the disease is being progressively clarified, its complexity remains vast. Moreover, some extremely infrequent cases of thrombotic thrombocytopenia following vaccination against SARS-CoV-2 infection have been observed. The present study aimed to map the signaling pathways of thrombocytopenia implicated in COVID-19, as well as in vaccine-induced thrombotic thrombocytopenia (VITT). The biomedical literature database, MEDLINE/PubMed, was thoroughly searched using artificial intelligence techniques for the semantic relations among the top 50 similar words (>0.9) implicated in COVID-19-mediated human infection or VITT. Additionally, STRING, a database of primary and predicted associations among genes and proteins (collected from diverse resources, such as documented pathway knowledge, high-throughput experimental studies, cross-species extrapolated information, automated text mining results, computationally predicted interactions, etc.), was employed, with the confidence threshold set at 0.7. In addition, two interactomes were constructed: i) A network including 119 and 56 nodes relevant to COVID-19 and thrombocytopenia, respectively; and ii) a second network containing 60 nodes relevant to VITT. Although thrombocytopenia is a dominant morbidity in both entities, three nodes were observed that corresponded to genes (AURKA, CD46 and CD19) expressed only in VITT, whilst ADAM10, CDC20, SHC1 and STXBP2 are silenced in VITT, but are commonly expressed in both COVID-19 and thrombocytopenia. The calculated average node degree was immense (11.9 in COVID-19 and 6.43 in VITT), illustrating the complexity of COVID-19 and VITT pathologies and confirming the importance of cytokines, as well as of pathways activated following hypoxic events. In addition, PYCARD, NLP3 and P2RX7 are key potential therapeutic targets for all three morbid entities, meriting further research. This interactome was based on wild-type genes, revealing the predisposition of the body to hypoxia-induced thrombosis, leading to the acute COVID-19 phenotype, the 'long-COVID syndrome', and/or VITT. Thus, common nodes appear to be key players in illness prevention, progression and treatment.

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.

Air Pollution and Cardiac Arrhythmias: From Epidemiological and Clinical Evidences to Cellular Electrophysiological Mechanisms

Cardiovascular disease is the leading cause of death worldwide and kills over 17 million people per year. In the recent decade, growing epidemiological evidence links air pollution and cardiac arrhythmias, suggesting a detrimental influence of air pollution on cardiac electrophysiological functionality. However, the proarrhythmic mechanisms underlying the air pollution-induced cardiac arrhythmias are not fully understood. The purpose of this work is to provide recent advances in air pollution-induced arrhythmias with a comprehensive review of the literature on the common air pollutants and arrhythmias. Six common air pollutants of widespread concern are discussed, namely particulate matter, carbon monoxide, hydrogen sulfide, sulfur dioxide, nitrogen dioxide, and ozone. The epidemiological and clinical reports in recent years are reviewed by pollutant type, and the recently identified mechanisms including both the general pathways and the direct influences of air pollutants on the cellular electrophysiology are summarized. Particularly, this review focuses on the impaired ion channel functionality underlying the air pollution-induced arrhythmias. Alterations of ionic currents directly by the air pollutants, as well as the alterations mediated by intracellular signaling or other more general pathways are reviewed in this work. Finally, areas for future research are suggested to address several remaining scientific questions.

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.

Assessment of Autonomic Nervous System Dysfunction in the Early Phase of Infection With SARS-CoV-2 Virus

BACKGROUND

We are facing the outburst of coronavirus disease 2019 (COVID-19) defined as a serious, multisystem, disorder, including various neurological manifestations in its presentation. So far, autonomic dysfunction (AD) has not been reported in patients with COVID-19 infection.

AIM

Assessment of AD in the early phase of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus).

PATIENTS AND METHODS

We analyzed 116 PCR positive COVID-19 patients. After the exclusion of 41 patients with associate diseases (CADG), partitioned to patients with diabetes mellitus, hypertension, and syncope, the remaining patients were included into a severe group (45 patients with confirmed interstitial pneumonia) and mild group (30 patients). Basic cardiovascular autonomic reflex tests (CART) were performed, followed by beat-to-beat heart rate variability (HRV) and systolic and diastolic blood pressure variability (BPV) analysis, along with baroreceptor sensitivity (BRS). Non-linear analysis of HRV was provided by Poincare Plot. Results were compared to 77 sex and age-matched controls.

RESULTS

AD (sympathetic, parasympathetic, or both) in our study has been revealed in 51.5% of severe, 78.0% of mild COVID-19 patients, and the difference compared to healthy controls was significant (p = 0.018). Orthostatic hypotension has been established in 33.0% COVID-19 patients compared to 2.6% controls (p = 0.001). Most of the spectral parameters of HRV and BPV confirmed AD, most prominent in the severe COVID-19 group. BRS was significantly lower in all patients (severe, mild, CADG), indicating significant sudden cardiac death risk.

CONCLUSION

Cardiovascular autonomic neuropathy should be taken into account in COVID-19 patients' assessment. It can be an explanation for a variety of registered manifestations, enabling a comprehensive diagnostic approach and further treatment.

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.

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.

Cardiac Corrected QT Interval Changes Among Patients Treated for COVID-19 Infection During the Early Phase of the Pandemic

IMPORTANCE

Critical illness, a marked inflammatory response, and viruses such as SARS-CoV-2 may prolong corrected QT interval (QTc).

OBJECTIVE

To evaluate baseline QTc interval on 12-lead electrocardiograms (ECGs) and ensuing changes among patients with and without COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included 3050 patients aged 18 years and older who underwent SARS-CoV-2 testing and had ECGs at Columbia University Irving Medical Center from March 1 through May 1, 2020. Patients were analyzed by treatment group over 5 days, as follows: hydroxychloroquine with azithromycin, hydroxychloroquine alone, azithromycin alone, and neither hydroxychloroquine nor azithromycin. ECGs were manually analyzed by electrophysiologists masked to COVID-19 status. Multivariable modeling evaluated clinical associations with QTc prolongation from baseline.

EXPOSURES

COVID-19, hydroxychloroquine, azithromycin.

MAIN OUTCOMES AND MEASURES

Mean QTc prolongation, percentage of patients with QTc of 500 milliseconds or greater.

RESULTS

A total of 965 patients had more than 2 ECGs and were included in the study, with 561 (58.1%) men, 198 (26.2%) Black patients, and 191 (19.8%) aged 80 years and older. There were 733 patients (76.0%) with COVID-19 and 232 patients (24.0%) without COVID-19. COVID-19 infection was associated with significant mean QTc prolongation from baseline by both 5-day and 2-day multivariable models (5-day, patients with COVID-19: 20.81 [95% CI, 15.29 to 26.33] milliseconds; P < .001; patients without COVID-19: -2.01 [95% CI, -17.31 to 21.32] milliseconds; P = .93; 2-day, patients with COVID-19: 17.40 [95% CI, 12.65 to 22.16] milliseconds; P < .001; patients without COVID-19: 0.11 [95% CI, -12.60 to 12.81] milliseconds; P = .99). COVID-19 infection was independently associated with a modeled mean 27.32 (95% CI, 4.63-43.21) millisecond increase in QTc at 5 days compared with COVID-19-negative status (mean QTc, with COVID-19: 450.45 [95% CI, 441.6 to 459.3] milliseconds; without COVID-19: 423.13 [95% CI, 403.25 to 443.01] milliseconds; P = .01). More patients with COVID-19 not receiving hydroxychloroquine and azithromycin had QTc of 500 milliseconds or greater compared with patients without COVID-19 (34 of 136 [25.0%] vs 17 of 158 [10.8%], P = .002). Multivariable analysis revealed that age 80 years and older compared with those younger than 50 years (mean difference in QTc, 11.91 [SE, 4.69; 95% CI, 2.73 to 21.09]; P = .01), severe chronic kidney disease compared with no chronic kidney disease (mean difference in QTc, 12.20 [SE, 5.26; 95% CI, 1.89 to 22.51; P = .02]), elevated high-sensitivity troponin levels (mean difference in QTc, 5.05 [SE, 1.19; 95% CI, 2.72 to 7.38]; P < .001), and elevated lactate dehydrogenase levels (mean difference in QTc, 5.31 [SE, 2.68; 95% CI, 0.06 to 10.57]; P = .04) were associated with QTc prolongation. Torsades de pointes occurred in 1 patient (0.1%) with COVID-19.

CONCLUSIONS AND RELEVANCE

In this cohort study, COVID-19 infection was independently associated with significant mean QTc prolongation at days 5 and 2 of hospitalization compared with day 0. More patients with COVID-19 had QTc of 500 milliseconds or greater compared with patients without COVID-19.

Pinocembrin alleviates lipopolysaccharide-induced myocardial injury and cardiac dysfunction in rats by inhibiting p38/JNK MAPK pathway

AIM

Recent studies have shown that, with its excellent anti-inflammatory and antioxidant effects, pinocembrin can reduce the occurrence of arrhythmia in myocardial infarction rats. However, whether it can alleviate lipopolysaccharide (LPS)-induced myocardial injury in rats has not been reported. Therefore, the purpose of this study was to investigate whether pinocembrin could alleviate myocardial injury and arrhythmia in rats with sepsis.

MATERIALS AND METHODS

Rats were intraperitoneally injected with LPS to simulate animal sepsis, and the caudal vein was injected with pinocembrin or normal saline for intervention. Transthoracic echocardiography, inflammatory factors, electrophysiological recording, histological analysis, and western-blot analysis were performed.

KEY FINDINGS

Compared with the control group, the rats in the LPS group had myocardial injury and cardiac dysfunction, and the incidence of ventricular arrhythmia increased. In addition, LPS resulted in the increase of p-c-Jun N-terminal kinase (JNK), p-p38 proteins in the myocardium, the levels of inflammatory factors in the blood and the apoptosis rate of left ventricular cardiomyocytes. And all these adverse effects were eliminated, thus confirming that pinocembrin has an excellent protective effect on the heart.

SIGNIFICANCE

Reducing the inflammatory response and cell apoptosis by inhibiting p38/JNK mitogen-activated protein kinase (MAPK) signaling pathway, pinocembrin can alleviate myocardial injury, cardiac dysfunction, and ventricular arrhythmia induced by LPS.

Sexual Dimorphisms, Anti-Hormonal Therapy and Cardiac Arrhythmias

Significant variations from the normal QT interval range of 350 to 450 milliseconds (ms) in men and 360 to 460 ms in women increase the risk for ventricular arrhythmias. This difference in the QT interval between men and women has led to the understanding of the influence of sex hormones on the role of gender-specific channelopathies and development of ventricular arrhythmias. The QT interval, which represents the duration of ventricular repolarization of the heart, can be affected by androgen levels, resulting in a sex-specific predilection for acquired and inherited channelopathies such as acquired long QT syndrome in women and Brugada syndrome and early repolarization syndrome in men. Manipulation of the homeostasis of these sex hormones as either hormonal therapy for certain cancers, recreational therapy or family planning and in transgender treatment has also been shown to affect QT interval duration and increase the risk for ventricular arrhythmias. In this review, we highlight the effects of endogenous and exogenous sex hormones in the physiological and pathological states on QTc variation and predisposition to gender-specific pro-arrhythmias.

Assessment of Autonomic Nervous System Dysfunction in the Early Phase of Infection With SARS-CoV-2 Virus

BACKGROUND

We are facing the outburst of coronavirus disease 2019 (COVID-19) defined as a serious, multisystem, disorder, including various neurological manifestations in its presentation. So far, autonomic dysfunction (AD) has not been reported in patients with COVID-19 infection.

AIM

Assessment of AD in the early phase of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus).

PATIENTS AND METHODS

We analyzed 116 PCR positive COVID-19 patients. After the exclusion of 41 patients with associate diseases (CADG), partitioned to patients with diabetes mellitus, hypertension, and syncope, the remaining patients were included into a severe group (45 patients with confirmed interstitial pneumonia) and mild group (30 patients). Basic cardiovascular autonomic reflex tests (CART) were performed, followed by beat-to-beat heart rate variability (HRV) and systolic and diastolic blood pressure variability (BPV) analysis, along with baroreceptor sensitivity (BRS). Non-linear analysis of HRV was provided by Poincare Plot. Results were compared to 77 sex and age-matched controls.

RESULTS

AD (sympathetic, parasympathetic, or both) in our study has been revealed in 51.5% of severe, 78.0% of mild COVID-19 patients, and the difference compared to healthy controls was significant (p = 0.018). Orthostatic hypotension has been established in 33.0% COVID-19 patients compared to 2.6% controls (p = 0.001). Most of the spectral parameters of HRV and BPV confirmed AD, most prominent in the severe COVID-19 group. BRS was significantly lower in all patients (severe, mild, CADG), indicating significant sudden cardiac death risk.

CONCLUSION

Cardiovascular autonomic neuropathy should be taken into account in COVID-19 patients' assessment. It can be an explanation for a variety of registered manifestations, enabling a comprehensive diagnostic approach and further treatment.

Lethal Arrhythmia (Torsade de Pointes) in COVID-19: An Event Synergistically Induced by Viral Associated Cardiac Injury, Hyperinflammatory Response, and Treatment Drug?

Arrhythmias in patients with coronavirus disease 2019 (COVID-19) are prevalent and deserve special attention because they are associated with an increased risk of fatal outcome. The mechanism of arrhythmia in COVID-19 remains unclear. Here, we report our first case of confirmed COVID-19 with documented Torsade de Pointes (TdP). A 64-year-old woman, previously healthy, presented to our emergency department with progressive shortness of breath, dry cough, and 1 week of fever. She was treated with chloroquine phosphate, meropenem, and ciprofloxacin. After 5 days of admission, her condition deteriorated and she was admitted to the intensive care unit. The patient had two episodes of malignant arrhythmias within 24 hours. The former was TdP, and the latter was a fatal pulseless ventricular tachycardia that occured even after chloroquine was discontinued. There was evidence of cardiac injury shown by increased serum level of troponin I. We propose a synergistic concept of lethal arrhythmia due to direct severe acute respiratory syndrome coronavirus (SARS-CoV)-2-associated cardiac injury, hyperinflammatory response, and drug-induced arrhythmia.

Cardiovascular impact of COVID-19 with a focus on children: A systematic review

BACKGROUND

Since the beginning of the pandemic, coronavirus disease-2019 (COVID-19) in children has shown milder cases and a better prognosis than adults. Although the respiratory tract is the primary target for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), cardiovascular involvement is emerging as one of the most significant and life-threatening complications of SARS-CoV-2 infection in adults.

AIM

To summarize the current knowledge about the potential cardiovascular involvement in pediatric COVID-19 in order to give a perspective on how to take care of them during the current pandemic emergency.

METHODS

Multiple searches in MEDLINE, PubMed were performed using the search terms "COVID-19" or "SARS-CoV-2" were used in combination with "myocardial injury" or "arrhythmia" or "cardiovascular involvement" or "heart disease" or "congenital heart disease" or "pulmonary hypertension" or "long QT" or "cardiomyopathies" or "channelopathies" or "Multisystem inflammatory system" or "PMIS" or "MIS-C" or "Pediatric multisystem inflammatory syndrome" or "myocarditis" or "thromboembolism to identify articles published in English language from January 1st, 2020 until July 31st, 2020. The websites of World Health Organization, Centers for Disease control and Prevention, and the Johns Hopkins Coronavirus Resource Center were reviewed to provide up to date numbers and infection control recommendations. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts concerning the subject were reviewed by the authors, and the data were extracted using a standardized collection tool. Data were subsequently analyzed with descriptive statistics. For Pediatric multisystemic inflammatory syndrome temporally associated with COVID-19 (PMIS), multiple meta-analyses were conducted to summarize the pooled mean proportion of different cardiovascular variables in this population in pseudo-cohorts of observed patients.

RESULTS

A total of 193 articles were included. Most publications used in this review were single case reports, small case series, and observational small-sized studies or literature reviews. The meta-analysis of 16 studies with size > 10 patients and with complete data about cardiovascular involvement in children with PMIS showed that PMIS affects mostly previously healthy school-aged children and adolescents presenting with Kawasaki disease-like features and multiple organ failure with a focus on the heart, accounting for most cases of pediatric COVID-19 mortality. They frequently presented cardiogenic shock (53%), ECG alterations (27%), myocardial dysfunction (52%), and coronary artery dilation (15%). Most cases required PICU admission (75%) and inotropic support (57%), with the rare need for extracorporeal membrane oxygenation (4%). Almost all of these children wholly recovered in a few days, although rare deaths have been reported (2%). Out of PMIS cases we identified 10 articles reporting sporadic cases of myocarditis, pulmonary hypertension and cardiac arrythmias in previously healthy children. We also found another 10 studies reporting patients with pre-existing heart diseases. Most cases consisted in children with severe COVID-19 infection with full recovery after intensive care support, but cases of death were also identified. The management of different cardiac conditions are provided based on current guidelines and expert panel recommendations.

CONCLUSION

There is still scarce data about the role of cardiovascular involvement in COVID-19 in children. Based on our review, children (previously healthy or with pre-existing heart disease) with acute COVID-19 requiring hospital admission should undergo a cardiac workup and close cardiovascular monitoring to identify and treat timely life-threatening cardiac complications.

Cardiac arrest and drug-related cardiac toxicity in the Covid-19 era. Epidemiology, pathophysiology and management

SARS-CoV-2 (Covid-19) infection has recently become a worldwide challenge with dramatic global economic and health consequences. As the pandemic is still spreading, new data concerning Covid-19 complications and related mechanisms become increasingly available. Accumulating data suggest that the incidence of cardiac arrest and its outcome are adversely affected during the Covid-19 period. This may be further exacerbated by drug-related cardiac toxicity of Covid-19 treatment regimens. Elucidating the underlying mechanisms that lead to Covid-19 associated cardiac arrest is imperative, not only in order to improve its effective management but also to maximize preventive measures. Herein we discuss available epidemiological data on cardiac arrest during the Covid-19 pandemic as well as possible associated causes and pathophysiological mechanisms and highlight gaps in evidence warranting further investigation. The risk of transmission during cardiopulmonary resuscitation (CPR) is also discussed in this review. Finally, we summarize currently recommended guidelines on CPR for Covid-19 patients including CPR in patients with cardiac arrest due to suspected drug-related cardiac toxicity in an effort to underscore the most important common points and discuss discrepancies proposed by established international societies.

Sex differences underlying preexisting cardiovascular disease and cardiovascular injury in COVID-19

The novel 2019 coronavirus disease (COVID-19), resulting from severe acute respiratory syndrome coronarvirus-2 (SARS-CoV-2) infection, typically leads to respiratory failure in severe cases; however, cardiovascular injury is reported to contribute to a substantial proportion of COVID-19 deaths. Preexisting cardiovascular disease (CVD) is among the most common risk factors for hospitalization and death in COVID-19 patients, and the pathogenic mechanisms of COVID-19 disease progression itself may promote the development of cardiovascular injury, increasing risk of in-hospital death. Sex differences in COVID-19 are becoming more apparent as mounting data indicate that males seem to be disproportionately at risk of severe COVID-19 outcome due to preexisting CVD and COVID-19-related cardiovascular injury. In this review, we will provide a basic science perspective on current clinical observations in this rapidly evolving field and discuss the interplay sex differences, preexisting CVD and COVID-19-related cardiac injury.