COVID-19 related acute necrotizing encephalopathy and acute myocarditis in an adult female: a novel case report of brain injury and myocarditis.

BACKGROUND: Acute necrotizing encephalopathy (ANE) and myocarditis are both acute, life-threatening conditions that can be triggered by COVID-19. We report a case of sequential ANE and myocarditis following a COVID-19 infection. CASE PRESENTATION: A 27-year-old female patient was brought to the emergency department due to episodes of fever for two days and a 9-h altered state of consciousness. Her condition rapidly developed into stuporous and hemodynamic instability within serval hours. Veno-arterial extracorporeal membrane oxygenation (ECMO) was rapidly initiated with other supportive treatments. The following-up MRI showed bilateral, symmetrically distributed lesions in the brainstem, bilateral hippocampal regions, and bilateral basal ganglia, consistent with ANE. The diagnosis was confirmed through the detection of SARS-CoV-2 and the exclusion of other potential causes. After weeks of medical treatment, her condition stabilized, and she was transferred for further rehabilitation treatment. CONCLUSIONS: This case study indicates that COVID-19 may simultaneously and rapidly affect the central nervous system and cardiovascular system, leading to poor outcomes. Accurate diagnosis and timely invasive bridging therapy, when necessary, can be lifesaving. Further exploration of potential mechanisms underlying COVID-19 central nervous system (CNS) and cardiovascular system manifestations will be important.

Case report of fatal immune-mediated myocarditis following treatment with davoceticept (ALPN-202), a PD-L1-dependent CD28 costimulator and dual PD-L1/CTLA-4 checkpoint inhibitor, in combination with pembrolizumab.

Engagement of programmed death-1 (PD-1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) can interfere with the CD28 signaling requisite for T-cell activation. While immune checkpoint inhibitors (ICIs) can relieve this suppression, they are unable to drive CD28 costimulation that may mechanistically contribute to ICI resistance. Thus, CD28 costimulation in the context of checkpoint inhibition may activate immunosuppressed T-cells in the tumor microenvironment. Davoceticept (ALPN-202) is an Fc fusion of a CD80 variant immunoglobulin domain (vIgD) designed to mediate PD-L1-dependent CD28 costimulation while inhibiting the PD-L1 and CTLA-4 checkpoints. PD-L1-restriction of davoceticept's CD28 costimulatory activity may minimize systemic T-cell activation and avoid untoward systemic toxicities. At the same time, preclinical studies have suggested that treatment with davoceticept during PD-1 inhibition may enhance antitumor activity by upregulating PD-L1, potentially synergizing with davoceticept's PD-L1-dependent costimulatory mechanism. This report details two cases of fatal cardiac events following treatment with davoceticept in combination with pembrolizumab (anti-PD-1) in the phase 1 study, NEON-2. Both events occurred in females in their 60s; one with choroidal melanoma and prior immunotherapy, the other with ICI-naïve microsatellite stable colorectal cancer. The clinical courses were fulminant with symptom onset at 2 weeks, followed by rapid decline. Cardiac autopsy from one patient confirmed immune-related myocarditis, and immunosequencing revealed expansion of a single T-cell clone that was not present in the pretreatment tumor. These cases highlight the importance of understanding risk factors that may contribute to immune-related myocarditis and other severe immune-related adverse events when CD28 agonism is targeted in the context of checkpoint inhibition.NEON-2 (NCT04920383).

[Characteristics of electrocardiogram in fulminant myocarditis].

Objective: To investugate the unique electrocardiogram (ECG) characteristics of fulminant myocarditis (FM) patients and provide important clues for the diagnosis of FM. Methods: This was a retrospective study. Patients diagnosed with acute myocarditis at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from February 2017 to April 2022 were enrolled and divided into fulminant myocarditis group (FM) and non-fulminant myocarditis group (NFM) according to clinical diagnosis. A total of 246 healthy people who underwent physical examination in the Health examination Center of Tongji Hospital at the same period were selected as the control group. The clinical data and ECG characteristics of the above 3 groups were analyzed and compared. Logistic regression model was used to analyze the influence of ECG parameters on left ventricular ejection fraction in FM patients. Receiver operating curves were constructed to evaluate the predictive value of different ECG parameters for FM. Results: A total of 180 patients were included in this study (FM group: n=123; NFM group: n=57), with an age of (35.0±16.2) years and 106 males (58.89%). Compared with NFM group, ECG was significantly abnormal in FM group, with a higher incidence of sinus tachycardia, ventricular tachycardia or ventricular fibrillation, escape rhythm, right bundle branch block, third degree atrioventricular block, ST-segment elevation, low voltage, prolonged QTc interval, and widened QRS wave in the FM group (all P<0.05). The ECG parameters showed that the amplitude of the full lead QRS wave in FM group was lower than that in NFM group (P<0.01). The average heart rate and QTc interval of FM group were significantly higher than those of NFM and control groups (all P<0.05). Although ST-segment elevation had a higher incidence in the FM group, ECG parameters showed that except for leads Ⅲ and aVF, the ST segment levels in all leads in the FM group were lower than those in the control group (all P<0.05). There was a statistically significant difference in some ST segment changes between FM and NFM groups, while there was no statistical difference between the NFM and control groups. Multivariate regression analysis showed that widened QRS wave and increased heart rate were the influencing factors for left ventricular systolic dysfunction in FM patients (OR=16.914, 95%CI: 1.367-209.224, P=0.028; OR=1.026, 95%CI: 1.010-1.042, P=0.001). Receiver operating curve analysis showed that heart rate>86.90 beat/min, QTc>431.50 ms, and RV5+SV1<1.72 mV had certain predictive value for FM diagnosis. Conclusions: FM patients displayed marked and severe ECG abnormalities, and characteristic changes in ECG can provide important first clues for the diagnosis of FM.

Lyme Carditis: A Rare Case of Heart Failure in the Absence of Ischemic Heart Disease.

BACKGROUND Lyme carditis typically presents with atrio-ventricular block; however, other cardiac manifestations, including varying EKG changes, myopericarditis and new-onset heart failure, can occur. CASE REPORT We report a case of a 52-year-old woman with past medical history significant for hypertension, chronic obstructive pulmonary disease, and chronic back pain who presented with new-onset heart failure in the setting of Lyme carditis. She presented with exertional dyspnea requiring supplemental oxygen, subjective fever, chills, fatigue, and arthralgia of 2-week duration. Her vital signs were consistent with hypotension and persistent bradycardia. An EKG displayed T-wave flattening in the anterior pre-cordial leads. Further work-up was suggestive of bilateral pulmonary edema and interstitial infiltrates, which required antibiotics and diuretics. Echocardiography demonstrated new-onset mildly depressed LV systolic dysfunction. Interestingly, coronary CTA revealed coronary arteries with no evidence of stenosis or plaque. She was found to have positive Lyme IgM and lgG antibodies. A diagnosis of Lyme myocarditis was considered and her antibiotic course was extended following multidisciplinary consensus. CONCLUSIONS This case report seeks to create awareness of the varying and atypical presentations of Lyme carditis, including new-onset heart failure in a patient without prior history of ischemic heart disease and uncommon EKG changes.

Long noncoding RNA NONHSAT122636.2 attenuates myocardial inflammation and apoptosis in myocarditis.

OBJECTIVE: The main pathological change of myocarditis is an inflammatory injury of cardiomyocytes. Long noncoding RNAs (lncRNAs) are closely related to inflammation, and our previous study showed that differential expression of lncRNAs is associated with myocarditis. This study aimed to investigate the impact of lncRNAs on the onset of myocarditis. METHODS: RNA expression was measured by quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Lipopolysaccharide (LPS) was used to induce inflammation in human cardiomyocytes (HCMs). The expression of inflammatory cytokines and myocardial injury markers was detected by enzyme-linked immunosorbent assay (ELISA) and RT-qPCR. Cell viability and apoptosis were measured by the cell counting kit-8 assay and flow cytometry. The binding force between lncRNA NONHSAT122636.2 and microRNA miRNA-2110 was detected using the dual-luciferase assay. RESULTS: NONHSAT122636.2 was dynamically expressed in patients with myocarditis and negatively correlated with inflammation severity. The overexpression of NONHSAT122636.2 improved inflammatory injury in LPS-stimulated HCMs. The study observed that there was a weak binding force between NONHSAT122636.2 and miR-2110. CONCLUSION: NONHSAT122636.2 attenuates myocardial inflammation and apoptosis in myocarditis. Additionally, its expression decreases in the peripheral blood of children suffering from myocarditis and in patients who are diagnosed for the first time showing higher diagnostic sensitivity and specificity. This decrease is negatively correlated with the degree of inflammation. Overall, the study suggests that NONHSAT122636.2 can be exploited as a potential diagnostic biomarker for pediatric myocarditis.

Viral Myocarditis as a Factor Leading to the Development of Heart Failure Symptoms, Including the Role of Parvovirus B19 Infection-Systematic Review.

Myocarditis (MC) is defined as an immunological inflammatory reaction with various etiologies, clinical presentations and prognoses within the myocardium. Currently, parvovirus B19 (PVB19) has become the main factor leading to this disease, replacing the previously dominant viruses A and B. In the case of chronic heart failure with subsequent dilated cardiomyopathy, approximately 67% have a viral etiology, and most of them are the result of PVB19 infection. However, the analysis showed a correlation between PVB19 infection and the risk of developing inflammatory dilated cardiomyopathy (DCMi). PVB19 is detected in 23% of patients with DCMi. Chronic infection may also contribute to progressive left ventricular failure in patients with a history of MC. The above effect suggests the active replication of PVB19 only in heart biopsies with inflammation due to MC or DCMi. Moreover, the supply of IFN-ß to suppress the active transcription of PVB19 accompanied by DCMi over a period of 6 months results in the normalization of NT-proBNP and an improvement in LVEF along with NYHA performance. The small number of reports on this topic and inaccuracies resulting from constantly conducted research and ongoing changes make it impossible to clearly answer the question of whether PVB19 is a factor inducing de novo MC and DCM or only accompanies the above conditions. However, large clinical cohort studies lead to the perception of PVB19 as a viral etiological agent capable of causing de novo MC together with DCMi.

Gasdermin-E-mediated pyroptosis drives immune checkpoint inhibitor-associated myocarditis via cGAS-STING activation.

Immune checkpoint inhibitor (ICI)-induced myocarditis involves intensive immune/inflammation activation; however, its molecular basis is unclear. Here, we show that gasdermin-E (GSDME), a gasdermin family member, drives ICI-induced myocarditis. Pyroptosis mediated by GSDME, but not the canonical GSDMD, is activated in myocardial tissue of mice and cancer patients with ICI-induced myocarditis. Deficiency of GSDME in male mice alleviates ICI-induced cardiac infiltration of T cells, macrophages, and monocytes, as well as mitochondrial damage and inflammation. Restoration of GSDME expression specifically in cardiomyocytes, rather than myeloid cells, in GSDME-deficient mice reproduces ICI-induced myocarditis. Mechanistically, quantitative proteomics reveal that GSDME-dependent pyroptosis promotes cell death and mitochondrial DNA release, which in turn activates cGAS-STING signaling, triggering a robust interferon response and myocardial immune/inflammation activation. Pharmacological blockade of GSDME attenuates ICI-induced myocarditis and improves long-term survival in mice. Our findings may advance the understanding of ICI-induced myocarditis and suggest that targeting the GSDME-cGAS-STING-interferon axis may help prevent and manage ICI-associated myocarditis.

Rare Presentation of Wide QRS Tachycardia in a Patient in Their 40s.

This article describes the case of a 40-year-old individual who presented with fulminant myocarditis. Initial ECG displayed sinus tachycardia with a heart rate of 117 bpm, QS complexes in leads V1-V3, ST-segment depression in leads II, III, aVF, V5-V6, and ST-segment elevation >0.2 mV in leads V1 through V3. The initial clinical assessment suggested an acute anteroseptal myocardial infarction. However, subsequent diagnostic evaluation through coronary angiography disclosed that the coronary arteries were normal. Therefore, clinicians should carefully consider the differential diagnosis between these conditions, as their management strategies differ markedly. Two hours after admission, the patient unexpectedly developed syncope. The ECG findings were consistent with the typical characteristics of bidirectional ventricular tachycardia. Our report described the appearance and morphology as well as mechanism of bidirectional ventricular tachycardia in detail. Additionally, we delineate differential diagnoses for disease that can cause bidirectional ventricular tachycardia, such as aconite poisoning, digoxin overdose, immune checkpoint inhibitor (ICI), myocardial ischemia, and hereditary channelopathies, such as catecholaminergic polymorphic ventricular tachycardia (CPVT) and Andersen-Tawil syndrome. Therefore, clinicians should recognize this ECG finding immediately and initiate appropriate treatment promptly as these measures may be vital in saving the patient's life.

Unveiling Cellular Identities and Gene Expression Pathways in Overlapping Myocarditis and Myositis.

Immune checkpoint therapies can drive antitumor responses and benefit patients but can also induce life-threatening immune-related adverse events such as myocarditis and myositis. These immune-related adverse events are rare but carry substantial morbidity and mortality. In this issue, Siddiqui and colleagues use single-cell RNA and T-cell receptor sequencing to identify novel cellular subsets and propose various mechanisms that could contribute to the pathogenesis of immune checkpoint inhibitor-associated myocarditis and myositis. These new insights should help move the field toward the development of improved treatment and prevention options, ultimately improving patient outcomes. See related article by Siddiqui et al., p. 964 (1).

Serum Concentrations of Matrix Metalloproteinase-1 and Procollagen Type I Carboxy Terminal Propeptide Discriminate Infarct-Like Myocarditis and Non-ST-Segment-Elevation Myocardial Infarction.

BACKGROUND: Biomarkers simplifying the diagnostic workup by discriminating between non-ST-segment-elevation myocardial infarction (NSTEMI) and infarct-like myocarditis are an unmet clinical need. METHODS AND RESULTS: A total of 105 subjects were categorized into groups as follows: ST-segment-elevation myocardial infarction (n=36), NSTEMI (n=22), infarct-like myocarditis (n=19), cardiomyopathy-like myocarditis (n=18), and healthy control (n=10). All subjects underwent cardiac magnetic resonance imaging, and serum concentrations of matrix metalloproteinase-1 (MMP-1) and procollagen type I carboxy terminal propeptide (PICP) were measured. Biomarker concentrations in subjects presenting with acute coronary syndrome and non-ST-segment-elevation, for example NSTEMI or infarct-like myocarditis, categorized as the non-ST-segment-elevation acute coronary syndrome-like cohort, were of particular interest for this study. Compared with healthy controls, subjects with myocarditis had higher serum concentrations of MMP-1 and PICP, while no difference was observed in individuals with myocardial infarction. In the non-ST-segment-elevation acute coronary syndrome-like cohort, MMP-1 concentrations discriminated infarct-like myocarditis and NSTEMI with an area under the receiver operating characteristic curve (AUC) of 0.95 (95% CI, 0.89-1.00), whereas high-sensitivity cardiac troponin T performed inferiorly (AUC, 0.74 [95% CI, 0.58-0.90]; P=0.012). Application of an optimal MMP-1 cutoff had 94.4% sensitivity (95% CI, 72.7%-99.9%) and 90.9% specificity (95% CI, 70.8%-98.9%) for the diagnosis of infarct-like myocarditis in this cohort. The AUC of PICP in this context was 0.82 (95% CI, 0.68-0.97). As assessed by likelihood ratio tests, incorporating MMP-1 or PICP with age and C-reactive protein into composite prediction models enhanced their diagnostic performance. CONCLUSIONS: MMP-1 and PICP could potentially be useful biomarkers for differentiating between NSTEMI and infarct-like myocarditis in individuals with non-ST-segment-elevation acute coronary syndrome-like presentation, though further research is needed to validate their clinical applicability.

Case report: Potential role of immunotherapy in thymic malignancies: a unique case of a durable and complete response upon an immune checkpoint inhibitor.

Thymic epithelial tumors are rare malignancies with an incidence of 1.7 cases per million people per year. They pose significant management challenges due to their association with autoimmune disorders. In this case report, we present the 21-year history of a patient diagnosed with advanced B2/B3 thymoma and Good's syndrome. The patient achieved a complete and durable response after receiving only two cycles of the immune checkpoint inhibitor Nivolumab. However, this positive outcome was accompanied by the development of severe immune-related myocarditis complicated by reactivation of cytomegalovirus. Moreover, the patient developed a highly uncommon subdiaphragmatic pararectal dissemination of the thymic tumor, which is a condition rarely described in the literature. Despite the success in achieving complete and durable response with immune checkpoint inhibitors, the emergence of immune-related adverse events highlights the potential challenges associated with these treatments, emphasizing the need for careful monitoring and a comprehensive understanding of the intricate interplay between cancer, immune system dysregulations and immunotherapy.

Coronavirus disease 2019-related myocarditis genes contribute to ECMO prognosis.

BACKGROUND: Acute myocardial injury, cytokine storms, hypoxemia and pathogen-mediated damage were the major causes responsible for mortality induced by coronavirus disease 2019 (COVID-19)-related myocarditis. These need ECMO treatment. We investigated differentially expressed genes (DEGs) in patients with COVID-19-related myocarditis and ECMO prognosis. METHODS: GSE150392 and GSE93101 were analyzed to identify DEGs. A Venn diagram was used to obtain the same transcripts between myocarditis-related and ECMO-related DEGs. Enrichment pathway analysis was performed and hub genes were identified. Pivotal miRNAs, transcription factors, and chemicals with the screened gene interactions were identified. The GSE167028 dataset and single-cell sequencing data were used to validate the screened genes. RESULTS: Using a Venn diagram, 229 overlapping DEGs were identified between myocarditis-related and ECMO-related DEGs, which were mainly involved in T cell activation, contractile actin filament bundle, actomyosin, cyclic nucleotide phosphodiesterase activity, and cytokine-cytokine receptor interaction. 15 hub genes and 15 neighboring DEGs were screened, which were mainly involved in the positive regulation of T cell activation, integrin complex, integrin binding, the PI3K-Akt signaling pathway, and the TNF signaling pathway. Data in GSE167028 and single-cell sequencing data were used to validate the screened genes, and this demonstrated that the screened genes CCL2, APOE, ITGB8, LAMC2, COL6A3 and TNC were mainly expressed in fibroblast cells; IL6, ITGA1, PTK2, ITGB5, IL15, LAMA4, CAV1, SNCA, BDNF, ACTA2, CD70, MYL9, DPP4, ENO2 and VEGFC were expressed in cardiomyocytes; IL6, PTK2, ITGB5, IL15, APOE, JUN, SNCA, CD83, DPP4 and ENO2 were expressed in macrophages; and IL6, ITGA1, PTK2, ITGB5, IL15, VCAM1, LAMA4, CAV1, ACTA2, MYL9, CD83, DPP4, ENO2, VEGFC and IL32 were expressed in vascular endothelial cells. CONCLUSION: The screened hub genes, IL6, ITGA1, PTK2, ITGB3, ITGB5, CCL2, IL15, VCAM1, GZMB, APOE, ITGB8, LAMA4, LAMC2, COL6A3 and TNFRSF9, were validated using GEO dataset and single-cell sequencing data, which may be therapeutic targets patients with myocarditis to prevent MI progression and adverse cardiovascular events.

Levosimendan: efficacy and safety in pediatric heart failure treatment.

OBJECTIVE: The objective of this study was to assess the effectiveness and safety of levosimendan as an alternative treatment for pediatric patients with decompensated heart failure unresponsive to conventional inotropes and to emphasize its role in enhancing cardiovascular stability. METHODS: A total of 15 pediatric patients with decompensated heart failure, stemming from acute fulminant myocarditis (53.3%) and post-congenital heart disease surgery complications (46.7%), received levosimendan. The evaluation focused on adverse effects, respiratory support requirements, and concurrent inotropic medication use during levosimendan treatment. Key cardiovascular parameters were assessed at 0, 6, 12, and 24 h post-levosimendan infusion. RESULTS: Levosimendan administration significantly improved key cardiovascular metrics. Left ventricular ejection fraction increased notably from 45±14.8% to 58±15.6% at 24 h (p<0.001). Systolic and diastolic blood pressures rose significantly, with systolic increasing from 79 (68-90) to 98 (89-109) mmHg and diastolic from 47 (40-57) to 66 (54-76) mmHg by 24 h (p<0.001). Heart rate decreased from 162 (111-175) to 132 (99-148) bpm (p=0.02), and lactate levels significantly decreased from 4.15 (2.3-6.5) to 1.85 (0.8-2.6) mmol/L within 6 h (p<0.001). CONCLUSION: Levosimendan demonstrates its significance in managing pediatric heart failure, indicating its safety and potential to enhance cardiac outcomes by reducing reliance on traditional inotropes.

Effect and mechanism of T lymphocytes on human induced pluripotent stem cell-derived cardiomyocytes via Proteomics.

BACKGROUND: Abnormalities in T cell activation play an important role in the pathogenesis of myocarditis, and persistent T cell responses can lead to autoimmunity and chronic cardiac inflammation, as well as even dilated cardiomyopathy. Although previous work has examined the role of T cells in myocarditis in animal models, the specific mechanism for human cardiomyocytes has not been investigated. METHODS: In this study, we constructed the human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and established the T cell-mediated cardiac injury model by co-culturing with activated CD4 + T or CD8 + T cells that were isolated from peripheral mononuclear blood to elucidate the pathogenesis of myocardial cell injury caused by inflammation. RESULTS: By combination of quantitative proteomics with tissue and cell immunofluorescence examination, we established a proteome profile of inflammatory myocardia from hiPSC-CMs with obvious cardiomyocyte injury and increased levels of lactate dehydrogenase content, creatine kinase isoenzyme MB and cardiac troponin. A series of molecular dysfunctions of hiPSC-CMs was observed and indicated that CD4 + cells could produce direct cardiomyocyte injury by activating the NOD-like receptor signals pathway. CONCLUSIONS: The data presented in our study established a proteome map of inflammatory myocardial based on hiPSC-CMs injury model. These results can provide guidance in the discovery of improved clinical treatments for myocarditis.

The complex interplay between encephalomyocarditis virus and the host defence system.

A variety of animals can be infected by encephalomyocarditis virus (EMCV). EMCV is the established causative agent of myocarditis and encephalitis in some animals. EMCV causes high fatality in suckling and weaning piglets, making pigs the most susceptible domestic animal species. Importantly, EMCV has zoonotic potential to infect the human population. The ability of the pathogen to avoid and undermine the initial defence mechanism of the host contributes to its virulence and pathogenicity. A large body of literature highlights the intricate strategies employed by EMCV to escape the innate immune machinery to suit its "pathogenic needs." Here, we also provide examples on how EMCV interacts with certain host proteins to dampen the infection process. Hence, this concise review aims to summarize these findings in a compendium of decades of research on this exciting yet underappreciated topic.

Long-term cardiovascular inflammation and fibrosis in a murine model of vasculitis induced by Lactobacillus casei cell wall extract.

Background: Kawasaki disease (KD), an acute febrile illness and systemic vasculitis, is the leading cause of acquired heart disease in children in industrialized countries. KD leads to the development of coronary artery aneurysms (CAA) in affected children, which may persist for months and even years after the acute phase of the disease. There is an unmet need to characterize the immune and pathological mechanisms of the long-term complications of KD. Methods: We examined cardiovascular complications in the Lactobacillus casei cell wall extract (LCWE) mouse model of KD-like vasculitis over 4 months. The long-term immune, pathological, and functional changes occurring in cardiovascular lesions were characterized by histological examination, flow cytometric analysis, immunofluorescent staining of cardiovascular tissues, and transthoracic echocardiogram. Results: CAA and abdominal aorta dilations were detected up to 16 weeks following LCWE injection and initiation of acute vasculitis. We observed alterations in the composition of circulating immune cell profiles, such as increased monocyte frequencies in the acute phase of the disease and higher counts of neutrophils. We determined a positive correlation between circulating neutrophil and inflammatory monocyte counts and the severity of cardiovascular lesions early after LCWE injection. LCWE-induced KD-like vasculitis was associated with myocarditis and myocardial dysfunction, characterized by diminished ejection fraction and left ventricular remodeling, which worsened over time. We observed extensive fibrosis within the inflamed cardiac tissue early in the disease and myocardial fibrosis in later stages. Conclusion: Our findings indicate that increased circulating neutrophil counts in the acute phase are a reliable predictor of cardiovascular inflammation severity in LCWE-injected mice. Furthermore, long-term cardiac complications stemming from inflammatory cell infiltrations in the aortic root and coronary arteries, myocardial dysfunction, and myocardial fibrosis persist over long periods and are still detected up to 16 weeks after LCWE injection.

Case Report: Non-ischemic Papillary Muscle Rupture due to MRSA Myocarditis with Concurrent Thromboembolic Myocardial Infarction Secondary to Infective Endocarditis.

Non-ischemic papillary muscle rupture (PMR) is rare. PMR caused by myocarditis in the presence of concurrent infective endocarditis (IE) and myocardial infarction (MI) has not been described. We report a 46-year-old male with recurrent MRSA bacteremia who presented in septic shock and suffered cardiac arrest. Echocardiography revealed acute mitral valve regurgitation resulting from posteromedial PMR. An intra-aortic balloon pump was implanted. Angiography revealed thrombotic occlusion of a small distal left circumflex artery. Emergent mitral valve replacement surgery was performed. MRSA myocarditis and IE were diagnosed by tissue cultures. Coexistence of myocarditis, IE, and MI poses a challenge in determining etiology.

Clinical Characteristics and Mechanisms of Acute Myocarditis.

REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05335928.