Clinically Suspected and Biopsy-Proven Myocarditis Temporally Associated with SARS-CoV-2 Infection.

We review current data on clinically suspected [European Society of Cardiology (ESC) 2013 criteria] and biopsy-proven [ESC and World Health Organization (WHO) criteria] myocarditis that is temporally associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. ESC/WHO etiological diagnosis of viral myocarditis is based on histological and immunohistological evidence of nonischemic myocyte necrosis and monolymphocytic infiltration, i.e., myocarditis, plus the identification of a specific cardiotropic virus by molecular techniques, in particular polymerase chain reaction (PCR)/in-situ hybridization, on endomyocardial biopsy (EMB)/autopsy tissue. There is not yet definitive EMB/autopsy proof that SARS-CoV-2 causes direct cardiomyocyte damage in association with histological myocarditis. Clinical epidemiology data suggest that myocarditis is uncommon for both SARS-CoV-2-positive and -negative PCR cases. We hypothesize that the rare virus-negative biopsy-proven cases may represent new-onset immune-mediated or latent pre-existing autoimmune forms,triggered or fostered by the hyperinflammatory state of severe COVID-19. We recommend the application of the ESC/WHO definitions and diagnostic criteria in future reports to avoid low-quality scientific information leading to an inaccurate estimate of myocarditis incidence based on misdiagnosis.

Cardiac involvement in eosinophilic granulomatosis with polyangiitis: acute eosinophilic myocarditis and chronic inflammatory cardiomyopathy.

OBJECTIVES: Currently, cardiac involvement is used to describe all eosinophilic granulomatosis with polyangiitis (EGPA) cardiac problems. However, heterogeneity exists among them. We aimed to depict the disease spectrum of EGPA cardiac involvement and identify high-risk population. METHODS: We included EGPA patients hospitalized in our center from 2012 to 2023 and in public databases. Based on the cardiac enzymes, cardiac magnetic resonance imaging, and endomyocardial biopsy results, the patients were divided into 3 groups: eosinophilic myocarditis (EGPA-EM), chronic inflammatory cardiomyopathy (EGPA-ICM) and EGPA-Control. Their clinical, laboratory, imaging results and prognoses were collected and compared. RESULTS: A total of 193 EGPA patients were included, 118 with cardiac involvement (74 EGPA-EM, 44 EGPA-ICM) and 75 control. Among EGPA-control, EGPA-ICM and EGPA-EM, eosinophil increased (6.12/8.71/10.42 × 109/l, p< 0.01), ANCA positivity decreased (41.33/31.82/14.86%, p< 0.01), and lung involvement reduced (73.33/72.73/43.24%, p= 0.02). In EGPA-EM, cardiac troponin further elevated (0.27 vs 6.00 ng/ml, p< 0.01), ejection fractions decreased (57.79 vs 33.20%, p< 0.01), while more ST-T abnormality was observed (41.89 vs 20.45%, p= 0.02). The prognosis of EGPA-EM was significantly worse, with 14.86% death rate, and 2-year event-free survival rate below 50%. Further, we proposed a LATE-EAST diagnostic score (7 items, 9 points) to discriminate EGPA-EM from EGPA-ICM using 4 points as threshold [AUC 0.85 (95%CI 0.78-0.92), sensitivity 0.78, specificity 0.86]. CONCLUSIONS: We first proposed different subtypes of cardiac involvement in EGPA. Identification and treatment of EGPA-EM needs improvement. LATE-EAST score could recognize the high-risk EGPA-EM effectively. Multi-disciplinary treatment is warranted, immunosuppressive therapy should be given timely and anti-IL-5 antibodies be tested in trials.

New insights gained from cellular landscape changes in myocarditis and inflammatory cardiomyopathy.

Advances in the etiological classification of myocarditis and inflammatory cardiomyopathy (ICM) have reached a consensus. However, the mechanism of myocarditis/ICM remains unclear, which affects the development of treatment and the improvement of outcome. Cellular transcription and metabolic reprogramming, and the interactions between cardiomyocytes and non-cardiomyocytes, such as the immune cells, contribute to the process of myocarditis/ICM. Recent efforts have been made by multi-omics techniques, particularly in single-cell RNA sequencing, to gain a better understanding of the cellular landscape alteration occurring in disease during the progression. This article aims to provide a comprehensive overview of the latest studies in myocarditis/ICM, particularly as revealed by single-cell sequencing.

Coordination chemistry suggests that independently observed benefits of metformin and Zn2+ against COVID-19 are not independent.

Independent trials indicate that either oral Zn2+ or metformin can separately improve COVID-19 outcomes by approximately 40%. Coordination chemistry predicts a mechanistic relationship and therapeutic synergy. Zn2+ deficit is a known risk factor for both COVID-19 and non-infectious inflammation. Most dietary Zn2+ is not absorbed. Metformin is a naked ligand that presumably increases intestinal Zn2+ bioavailability and active absorption by cation transporters known to transport metformin. Intracellular Zn2+ provides a natural buffer of many protease reactions; the variable "set point" is determined by Zn2+ regulation or availability. A Zn2+-interactive protease network is suggested here. The two viral cysteine proteases are therapeutic targets against COVID-19. Viral and many host proteases are submaximally inhibited by exchangeable cell Zn2+. Inhibition of cysteine proteases can improve COVID-19 outcomes and non-infectious inflammation. Metformin reportedly enhances the natural moderating effect of Zn2+ on bioassayed proteome degradation. Firstly, the dissociable metformin-Zn2+ complex could be actively transported by intestinal cation transporters; thereby creating artificial pathways of absorption and increased body Zn2+ content. Secondly, metformin Zn2+ coordination can create a non-natural protease inhibitor independent of cell Zn2+ content. Moderation of peptidolytic reactions by either or both mechanisms could slow (a) viral multiplication (b) viral invasion and (c) the pathogenic host inflammatory response. These combined actions could allow development of acquired immunity to clear the infection before life-threatening inflammation. Nirmatrelvir (Paxlovid®) opposes COVID-19 by selective inhibition the viral main protease by a Zn2+-independent mechanism. Pending safety evaluation, predictable synergistic benefits of metformin and Zn2+, and perhaps metformin/Zn2+/Paxlovid® co-administration should be investigated.

New-onset heart failure in infants: when the aetiological diagnosis becomes a challenge.

This study aimed to report the findings of cardiac magnetic resonance imaging (CMR) with quantitative mappings in infants presenting with new-onset heart failure, as well as to assess the capabilities of endomyocardial biopsy (EMB) and CMR in detecting inflammatory cardiomyopathies and determining their etiology. In a prospective analysis of infants who underwent CMR with tissue mappings, EMB, and genetic testing, the sample was categorized into two groups: those with inflammatory cardiomyopathy and negative genetics (indicative of possible myocarditis) and those with positive genetics (indicative of possible dilated cardiomyopathy). All patients exhibited similar clinical presentations, echocardiographic dysfunction, and elevated troponins and NT-proBNP levels. Additionally, they all met the diagnostic criteria for inflammatory cardiomyopathy based on EMB findings (≥14 mononuclear cells, ≥7 T-lymphocytes/mm2). EMB results unveiled significant differences in the presence of inflammation and edema between the two groups, with higher troponin levels correlating with increased inflammation. Notably, when focusing on CMR, neither the classic criteria nor the 2018 Lake Louise criteria (LLC) could effectively differentiate between the two groups. Only late gadolinium enhancement (LGE) appeared to be associated with myocarditis in this cohort, while other LLC and tissue mappings did not exhibit a similar correlation. Importantly, there was no observed correlation between the inflammation detected through EMB and CMR. CONCLUSIONS: The onset of heart dysfunction in infants can result from either inherited factors or viral infections, both of which may involve inflammation. However, the precise role of EMB and CMR in determining the etiology of such cases remains poorly defined. While CMR demonstrates high sensitivity in detecting inflammation, our experience suggests that it may not effectively differentiate between these two groups. A comprehensive diagnostic approach is essential when addressing this challenge, which includes considering EMB (with attention to the number of T-lymphocytes and the presence of oedema), specific CMR criteria, notably LGE and tissue mappings, as well as the identification of viral agents in cardiac tissue and troponin levels. Additionally, genetic tests should be conducted when evaluating these patients. WHAT IS KNOWN: • EMB is the gold standard diagnostic test for myocarditis but it is not universally accepted. • The diagnostic value of the 2018-LLC in pediatric patients is still undefined. WHAT IS NEW: • Both EMB and CMR may show inflammation in infants with new-onset heart failure of any aetiology. • A global approach should be used when facing this diagnostic challenge, including the EMB (number of T-lymphocytes and oedema), some CMR criteria, specially LGE and mappings, the detection of viral agents in cardiac tissue and troponins. Genetic tests should also be performed when studying these patients.

Epstein-Barr Virus Lytic Transcripts Correlate with the Degree of Myocardial Inflammation in Heart Failure Patients.

The Epstein-Barr virus (EBV) is frequently found in endomyocardial biopsies (EMBs) from patients with heart failure, but the detection of EBV-specific DNA has not been associated with progressive hemodynamic deterioration. In this paper, we investigate the use of targeted next-generation sequencing (NGS) to detect EBV transcripts and their correlation with myocardial inflammation in EBV-positive patients with heart failure with reduced ejection fraction (HFrEF). Forty-four HFrEF patients with positive EBV DNA detection and varying degrees of myocardial inflammation were selected. EBV-specific transcripts from EMBs were enriched using a custom hybridization capture-based workflow and, subsequently, sequenced by NGS. The short-read sequencing revealed the presence of EBV-specific transcripts in 17 patients, of which 11 had only latent EBV genes and 6 presented with lytic transcription. The immunohistochemical staining for CD3+ T lymphocytes showed a significant increase in the degree of myocardial inflammation in the presence of EBV lytic transcripts, suggesting a possible influence on the clinical course. These results imply the important role of EBV lytic transcripts in the pathogenesis of inflammatory heart disease and emphasize the applicability of targeted NGS in EMB diagnostics as a basis for specific treatment.

Immunosuppressive therapy in virus-negative inflammatory cardiomyopathy: 20-year follow-up of the TIMIC trial.

AIMS: Long-term results of the Tailored IMmunosuppression in virus-negative Inflammatory Cardiomyopathy (TIMIC) trial protocol have been evaluated. METHODS AND RESULTS: Eighty-five patients with endomyocardial biopsy-proven virus-negative chronic inflammatory cardiomyopathy were enrolled in the randomized, double-blind, placebo-controlled TIMIC trial and received prednisone and azathioprine (n = 43) vs. placebo (n = 42) for 6 months. Immunosuppressive treatment promoted an improvement in cardiac function in 88% of the cases compared with none of the patients in the placebo group, which were switched to a 6-month immunosuppressive therapy at the end of the 6-month study period. Long-term (up to 20 years) clinical outcomes of the whole cohort of 85 patients originally enrolled in the TIMIC trial (Group A) were compared with those of a 1:2 propensity score-matched control cohort of patients untreated with the TIMIC protocol (Group B) and followed for a comparable period of time. The primary outcome was a composite of cardiovascular death and heart transplantation. At long-term follow-up, the risk of cardiovascular death [hazard ratio (HR) 6.77; 95% confidence interval (CI) 2.36-19.45] and heart transplantation (HR 7.92; 95% CI 1.80-34.88) was significantly higher in Group B patients. Group A showed a persistent improvement in the left ventricular ejection fraction compared with Group B (HR 7.24; 95% CI 3.05-17.18). A higher number of Group B patients underwent implantable cardioverter defibrillator implantation. The incidence of recurrent myocarditis was similar between groups, and patients with evidence of a recurrent cardiac inflammatory process promptly responded to a TIMIC protocol application. CONCLUSION: Virus-negative inflammatory cardiomyopathy benefits from immunosuppressive therapy even after long-term follow-up. Recurrence appears to respond to a new TIMIC protocol application.

Sudden death of a 12-year-old boy with severe myocardial fibrosis due to inapparent chronic myocarditis.

Sudden death due to unknown cardiac disease in children is an unusual occurrence. An apparently healthy 12-year-old boy without any physical restrictions collapsed suddenly and died despite cardiopulmonary resuscitation. The main autopsy finding was extensive scarring of the myocardium, especially the interventricular septum. This extensive scarring was exceptional for the young age. Histologically, replacement-type fibrosis with patchy lymphomonocytic infiltrate and infiltration by macrophages were observed. The case was diagnosed as chronic myocarditis, which may have progressed to dilated cardiomyopathy with inflammation or inflammatory cardiomyopathy.

Sarcoidosis-Related Cardiomyopathy: Current Knowledge, Challenges, and Future Perspectives State-of-the-Art Review.

The prevalence of sarcoidosis-related cardiomyopathy is increasing. Sarcoidosis impacts cardiac function through granulomatous infiltration of the heart, resulting in conduction disease, arrhythmia, and/or heart failure. The diagnosis of cardiac sarcoidosis (CS) can be challenging and requires clinician awareness as well as differentiation from overlapping diagnostic phenotypes, such as other forms of myocarditis and arrhythmogenic cardiomyopathy. Clinical manifestations, extracardiac involvement, histopathology, and advanced cardiac imaging can all lend support to a diagnosis of CS. The mainstay of therapy for CS is immunosuppression; however, no prospective clinical trials exist to guide management. Patients may progress to developing advanced heart failure or ventricular arrhythmia, for which ventricular assist device therapies or heart transplantation may be considered. The existing knowledge gaps in CS call for an interdisciplinary approach to both patient care and future investigation to improve mechanistic understanding and therapeutic strategies.

Characteristics and Outcomes of Patients with Inflammatory Cardiomyopathies Receiving Mechanical Circulatory Support: An STS-INTERMACS Registry Analysis.

BACKGROUND: Durable mechanical circulatory support (MCS) therapy improves survival in patients with advanced heart failure. Knowledge regarding the outcomes experienced by patients with inflammatory cardiomyopathy (CM) who receive durable MCS therapy is limited. METHODS AND RESULTS: We compared patients with inflammatory CM with patients with idiopathic dilated CM enrolled in the STS-INTERMACS registry. Among 19,012 patients, 329 (1.7%) had inflammatory CM and 5978 had idiopathic dilated CM (31.4%). The patients with inflammatory CM were younger, more likely to be White, and women. These patients experienced more preoperative arrhythmias and higher use of temporary MCS. Patients with inflammatory CM had a higher rate of early adverse events (<3 months after device implant), including bleeding, arrhythmias, non-device-related infections, neurologic dysfunction, and respiratory failure. The rate of late adverse events (≥3 months) was similar in the 2 groups. Patients with inflammatory CM had a similar 1-year (80% vs 84%) and 2-year (72% vs 76%, P = .15) survival. Myocardial recovery resulting in device explant was more common among patients with inflammatory CM (5.5% vs 2.3%, P < .001). CONCLUSIONS: Patients with inflammatory CM who received durable MCS appear to have a similar survival compared with patients with idiopathic dilated CM despite a higher early adverse event burden. Our findings support the use of durable MCS in an inflammatory CM population.

Diagnosis, management, and outcome of cardiac sarcoidosis and giant cell myocarditis: a Swedish single center experience.

BACKGROUND: Cardiac sarcoidosis (CS) and giant cell myocarditis (GCM) are rare diseases that share some similarities, but also display different clinical and histopathological features. We aimed to compare the demographics, clinical presentation, and outcome of patients diagnosed with CS or GCM. METHOD: We compared the clinical data and outcome of all adult patients with CS (n = 71) or GCM (n = 21) diagnosed at our center between 1991 and 2020. RESULTS: The median (interquartile range) follow-up time for patients with CS and GCM was 33.5 [6.5-60.9] and 2.98 [0.6-40.9] months, respectively. In the entire cohort, heart failure (HF) was the most common presenting manifestation (31%), followed by ventricular arrhythmias (25%). At presentation, a left ventricular ejection fraction of < 50% was found in 54% of the CS compared to 86% of the GCM patients (P = 0.014), while corresponding proportions for right ventricular dysfunction were 24% and 52% (P = 0.026), respectively. Advanced HF (NYHA ≥ IIIB) was less common in CS (31%) than in GCM (76%). CS patients displayed significantly lower circulating levels of natriuretic peptides (P < 0.001) and troponins (P = 0.014). Eighteen percent of patients with CS included in the survival analysis reached the composite endpoint of death or heart transplantation (HTx) compared to 68% of patients with GCM (P < 0.001). CONCLUSION: GCM has a more fulminant clinical course than CS with severe biventricular failure, higher levels of circulating biomarkers and an increased need for HTx. The histopathologic diagnosis remained key determinant even after adjustment for markers of cardiac dysfunction.

Electrophysiological, structural, and functional disorders in patients with inflammatory cardiomyopathy secondary to inflammatory myopathy.

BACKGROUND: Inflammatory cardiomyopathy (IC) is a syndrome with chronic myocarditis and cardiac remodeling. This study aimed to explore predicting factors of adverse outcomes in patients with IC secondary to idiopathic inflammatory myopathy (IIM-IC). METHODS: By means of a single-center retrospective study, 52 patients with IIM-IC at Peking Union Medical College Hospital were identified from January 1999 to June 2019. Electrocardiogram and echocardiography data were analyzed for the primary outcome (defined as all-cause death) and secondary outcomes (defined as re-hospitalization of heart failure and all-cause death), using regression and survival analysis. RESULTS: The prevalence of atrial fibrillation, ventricular tachycardia, Q-wave abnormality, left ventricular conduction abnormalities, and reduced left ventricular ejection fraction (LVEF) (≤40%) were 65.4%, 67.3%, 67.3%, 61.6%, and 50.5%. After a median follow-up of 2 years (IQR 0.8-3.0), 26 cases were readmitted due to heart failure. Twenty-two deaths were recorded, including 20 cardiogenic deaths. Among the patients with adverse events, the incidence of poor R-wave progression, low-voltage of the limb leads, Q-wave abnormality, QRS duration >130 ms, left ventricular enlargement, and impaired systolic function were higher. Kaplan-Meier analysis showed that Q-wave abnormality, limb leads low-voltage, LVEF ≤40%, and left ventricular end-diastolic dimension >60 mm were correlated with shorter survival. However, multivariate Cox regression analysis revealed that only Q-wave abnormality (HR = 12.315) and LVEF ≤40% (HR = 5.616) were independent risk factors for all-cause death. CONCLUSION: Q-wave abnormality and reduced LVEF are predictive of poor prognosis in patients with IIM-IC.

State-of-the-Art of Endomyocardial Biopsy on Acute Myocarditis and Chronic Inflammatory Cardiomyopathy.

PURPOSE OF REVIEW: Histologic evidence of myocardial inflammatory infiltrate not secondary to an ischemic injury is required by current diagnostic criteria to reach a definite diagnosis of myocarditis. Endomyocardial biopsy (EMB) is therefore often indicated for the diagnosis of myocarditis, although it may lack sufficient sensitivity considering the limited possibility of myocardial sampling. Improving the diagnostic yield and utility of EMB is of high priority in the fields of heart failure cardiology and myocarditis in particular. The aim of the present review is to highlight indications, strengths, and shortcomings of current EMB techniques, and discuss innovations currently being tested in ongoing clinical studies, especially in the setting of acute myocarditis and chronic inflammatory cardiomyopathy. RECENT FINDINGS: EMB provides unique diagnostic elements and prognostic information which can effectively guide the treatment of myocarditis. Issues affecting the diagnostic performance in the setting of acute myocarditis and chronic inflammatory cardiomyopathies will be discussed in this review in the light of recent expert consensus documents on the management of these conditions and on indication to EMB. Recent innovations using electroanatomic mapping (EAM)-guided EMB and fluoroscopic-guided EMB during temporary mechanical circulatory support have improved the utility of the procedure. EMB remains an important diagnostic test whose results need to be interpreted in the context of (1) clinical pre-test probability, (2) timing of sampling, (3) quality of sampling (4) site of sampling, (5) histologic type of myocarditis, and (6) analytic methods that are applied. Herein we will review these caveats as well as perspectives and innovations related to the use of this diagnostic tool.

Biomarkers for Myocarditis and Inflammatory Cardiomyopathy.

PURPOSE OF REVIEW: Myocarditis is a disease caused by inflammation of the heart that can progress to dilated cardiomyopathy, heart failure, and eventually death in many patients. Several etiologies are implicated in the development of myocarditis including autoimmune, drug-induced, infectious, and others. All causes lead to inflammation which causes damage to the myocardium followed by remodeling and fibrosis. This review aims to summarize recent findings in biomarkers for myocarditis and highlight the most promising candidates. RECENT FINDINGS: Current methods of diagnosing myocarditis, including imaging and endomyocardial biopsy, are invasive, expensive, and often not done early enough to affect progression. Research is being done to find biomarkers of myocarditis that are cost-effective, accurate, and prognostically informative. These biomarkers would allow for earlier screening for myocarditis, as well as earlier treatment, and a better understanding of the disease course for specific patients. Early diagnosis of myocarditis with biomarkers may allow for prompt treatment to improve outcomes in patients.

Intramyocardial Inflammation after COVID-19 Vaccination: An Endomyocardial Biopsy-Proven Case Series.

Myocarditis in response to COVID-19 vaccination has been reported since early 2021. In particular, young male individuals have been identified to exhibit an increased risk of myocardial inflammation following the administration of mRNA-based vaccines. Even though the first epidemiological analyses and numerous case reports investigated potential relationships, endomyocardial biopsy (EMB)-proven cases are limited. Here, we present a comprehensive histopathological analysis of EMBs from 15 patients with reduced ejection fraction (LVEF = 30 (14-39)%) and the clinical suspicion of myocarditis following vaccination with Comirnaty® (Pfizer-BioNTech) (n = 11), Vaxzevria® (AstraZenica) (n = 2) and Janssen® (Johnson & Johnson) (n = 2). Immunohistochemical EMB analyses reveal myocardial inflammation in 14 of 15 patients, with the histopathological diagnosis of active myocarditis according the Dallas criteria (n = 2), severe giant cell myocarditis (n = 2) and inflammatory cardiomyopathy (n = 10). Importantly, infectious causes have been excluded in all patients. The SARS-CoV-2 spike protein has been detected sparsely on cardiomyocytes of nine patients, and differential analysis of inflammatory markers such as CD4+ and CD8+ T cells suggests that the inflammatory response triggered by the vaccine may be of autoimmunological origin. Although a definitive causal relationship between COVID-19 vaccination and the occurrence of myocardial inflammation cannot be demonstrated in this study, data suggest a temporal connection. The expression of SARS-CoV-2 spike protein within the heart and the dominance of CD4+ lymphocytic infiltrates indicate an autoimmunological response to the vaccination.

A Case of Chronic Heart Failure Complicated by Primary Biliary Cholangitis and Skeletal Myopathy.

Several autoantigens related to inflammatory myopathy have been identified. Antimitochondrial antibody M2 (AMA-M2) is known as one of the serologic hallmarks of primary biliary cholangitis (PBC). There have been several reports on the association between AMA-M2 and various types of inflammatory myopathy, including cardiomyopathy. We report a case of a 58-year-old man with decompensated heart failure who also had PBC and skeletal inflammatory myopathy. Endomyocardial biopsy revealed severe fibrotic replacement of the myocardium without massive inflammatory infiltration, which was pathologically similar to what happens in dilated cardiomyopathy (DCM). Although the potential relationship between chronic autoimmune inflammation and DCM has been discussed, the concept of the inflammatory DCM has not yet been established. When we see elevated liver enzymes, and which is not simply due to congestive hepatopathy, we should consider the coexisting disease such as PBC.

Effect of immunosuppressive therapy in inflammatory cardiomyopathy: data from The Czech Inflammatory Cardiomyopathy Immunosuppressive Trial.

INTRODUCTION: The indications for specific treatment in the cases of inflammatory cardiomyopathy are based on limited data from several small clinical trials. AIM: A comparison of the effect of two dose regimens of combined immunosuppressive therapy by adding them to conventional heart failure therapy and comparing them with conventional heart failure therapy alone in patients with inflammatory cardiomyopathy. METHODS AND STUDY POPULATION: We enrolled 20 patients; mean age 46.10±7.33 years, duration of symptoms <6 months, LVEF ≤40 %, NYHA class II-IV, with biopsy­proven myocarditis. Patients were randomly separated into groups treated with immunosuppressive therapy in addition to conventional heart failure therapy or to a group treated with conventional heart failure therapy alone. Clinical and echocardiographic parameters were evaluated. RESULTS: The baseline values of LVEF in the group of immunosuppressive therapy (LVEF 22.3±4.7 %) were similar to those in the group treated with conventional heart failure therapy (LVEF 21.7±4.7 %; p=0.757). After twelve months there was no statistically significant difference in LVEF between the two studied groups (LVEF 33.7±9.5 % for the immunosuppressive therapy group and 41.3±13.0 % for the conventional therapy group; p=0.175). CONCLUSION: In our study population, we proved no positive effect of combined immunosuppressive therapy on the left ventricular function over 12 months. The main limitation of the study is the small number of enrolled patients (Tab. 4, Fig. 1, Ref. 35).

A case of cardiac sarcoidosis mimicking Brugada syndrome.

A 17-year-old boy was admitted for management of ventricular fibrillation (VF) with intermittent Brugada pattern on ECG. On evaluation, cardiac MRI revealed myocardial scar and mediastinal lymphadenopathy. 18-Fluorodeoxyglucose positron emission tomography scan showed inflammation in the heart, lungs, and lymph nodes. He was diagnosed as a case of cardiac sarcoidosis (CS) and treated with steroids. However, there was a reactivation of cardiac inflammation and the development of a second VF storm. Following catheter ablation, the patient's arrhythmia improved. This report highlights the inflammation due to CS mimicking channelopathic features.

Plasminogen activator inhibitor-1 reduces cardiac fibrosis and promotes M2 macrophage polarization in inflammatory cardiomyopathy.

Plasminogen activator inhibitor-1 (PAI-1) has a cardioprotective function in mice by repressing cardiac fibrosis through TGF-ß and plasminogen-mediated pathways. In addition it is known to be involved in the recruitment and polarization of monocytes/macrophages towards a M2 phenotype in cancer. Here, we investigated the expression of PAI-1 in human dilated cardiomyopathy (DCM) and inflammatory dilated cardiomyopathy (DCMi) and its effect on cardiac fibrosis and macrophage polarization. We retrospectively analyzed endomyocardial biopsies (EMBs) of patients with DCM or DCMi for PAI-1 expression by immunohistochemistry. Furthermore, EMBs were evaluated for the content of fibrotic tissue, number of activated myofibroblasts, TGF-ß expression, as well as for M1 and M2 macrophages. Patients with high-grade DCMi (DCMi-high, CD3+ lymphocytes > 30 cells/mm2) had significantly increased PAI-1 levels compared to DCM and low-grade DCMi patients (DCMi-low, CD3+ lymphocytes = 14-30 cells/mm2) (15.5 ± 0.4% vs. 1.0 ± 0.1% and 4.0 ± 0.1%, p ≤ 0.001). Elevated PAI-1 expression in DCMi-high subjects was associated with a diminished degree of cardiac fibrosis, decreased levels of TGF-ß and reduced number of myofibroblasts. In addition, DCMi-high patients revealed an increased proportion of non-classical M2 macrophages towards classical M1 macrophages, indicating M2 macrophage-favoring properties of PAI-1 in inflammatory cardiomyopathies. Our findings give evidence that elevated expression of cardiac PAI-1 in subjects with high-grade DCMi suppresses fibrosis by inhibiting TGF-ß and myofibroblast activation. Moreover, our data indicate that PAI-1 is involved in the polarization of M2 macrophages in the heart. Thus, PAI-1 could serve as a potential prognostic biomarker and as a possible therapeutic target in inflammatory cardiomyopathies.

Clinically Suspected Myocarditis in the Course of Severe Acute Respiratory Syndrome Novel Coronavirus-2 Infection: Fact or Fiction?

Cardiac complications, including clinically suspected myocarditis, have been described in novel coronavirus disease 2019. Here, we review current data on suspected myocarditis in the course of severe acute respiratory syndrome novel coronavirus-2 (SARS-CoV-2) infection. Hypothetical mechanisms to explain the pathogenesis of troponin release in patients with novel coronavirus disease 2019 include direct virus-induced myocardial injury (ie, viral myocarditis), systemic hyperinflammatory response (ie, cytokine storm), hypoxemia, downregulation of angiotensin-converting enzyme 2, systemic virus-induced endothelialitis, and type 1 and type 2 myocardial infarction. To date, despite the fact that millions of SARS-CoV-2 infections have been diagnosed worldwide, there is no definitive proof that SARS-CoV-2 is a novel cardiotropic virus causing direct cardiomyocyte damage. Diagnosis of viral myocarditis should be based on the molecular assessment of endomyocardial biopsy or autopsy by polymerase chain reaction or in-situ hybridization. Blood, sputum, or nasal and throat swab virology testing are insufficient and do not correlate with the myocardial involvement of a given pathogen. Data from endomyocardial biopsies and autopsies in clinically suspected SARS-CoV-2 myocarditis are scarce. Overall, current clinical epidemiologic data do not support the hypothesis that viral myocarditis is caused by SARS-CoV-2, or that it is common. More endomyocardial biopsy and autopsy data are also needed for a better understanding of pathogenesis of clinically suspected myocarditis in the course of SARS-CoV-2 infection, which may include virus-negative immune-mediated or already established subclinical autoimmune forms, triggered or accelerated by the hyperinflammatory state of severe novel coronavirus disease 2019.