Effect of N­terminal region of human parvovirus B19­VP1 unique region on cardiac injury in naïve mice.

A unique region of human parvovirus B19 virus­VP1 (B19V­VP1u) has been linked to a variety of cardiac disorders. However, the precise role of B19V­VP1u in inducing cardiac injury remains unknown. The present study investigated the effects of B19V­VP1u and different regions of B19V­VP1u, including B19V­VP1uA (residues 1­60), B19V­VP1uB (residues 61­129), B19V­VP1uC (residues 130­195) and B19V­VP1uD (residues 196­227), on inducing cardiac injury in naïve mice by zymography, immunoblotting, H&E staining and cytokine immunoassay. A significantly higher MMP­9/MMP­2 ratio and increased levels of inflammatory cytokines, including IL­6 and IL­1ß, were detected in the left ventricles of the mice injected with B19V­non­structural protein 1 (B19V­NS1) and B19V­VP1u, accompanied by increased expression levels of phosphorylated (p­)ERK and p­P38. Significantly upregulated expression levels of atrial natriuretic peptide (ANP), heart­type fatty acid­binding protein (H­FABP) and creatine kinase isoenzyme­MB (CK­MB), which are well­known cardiac injury markers, as well as increased infiltration of lymphocytes, were detected in the left ventricles of the mice injected with B19V­VP1, B19V­NS1 and B19V­VP1u. Moreover, a significantly higher MMP­9/MMP­2 ratio and increased levels of IL­6 and IL­1ß were observed in the left ventricles of the mice injected with B19V­VP1u, B19V­VP1u­A, B19V­VP1u­B and B19V­VP1u­C, accompanied by upregulated p­ERK and p­P38 expression. Notably, significantly lower levels of IL­6 and IL­1ß were observed in the left ventricles of the mice injected with B19V­VP1uD. Furthermore, significantly increased ANP, H­FABP and CK­MB expression levels were detected in the left ventricles of the mice injected with B19V­VP1u, B19V­VP1u­A and B19V­VP1u­B, along with enhanced infiltration of lymphocytes. Significantly higher serum IL­1ß, IL­6, TNF­α and IFN­Î³ levels were also detected in the mice injected with B19V­VP1u, B19V­VP1u­A and B19V­VP1u­B. To the best of our knowledge, the findings of the present study were the first to demonstrate that the N­terminal region (residues 1­129) of B19V­VP1u induces an increase in the levels of cardiac injury markers, thus providing evidence for understanding the possible functional regions within B19V­VP1u.

Cardiomyocytes recruit monocytes upon SARS-CoV-2 infection by secreting CCL2.

Heart injury has been reported in up to 20% of COVID-19 patients, yet the cause of myocardial histopathology remains unknown. Here, using an established in vivo hamster model, we demonstrate that SARS-CoV-2 can be detected in cardiomyocytes of infected animals. Furthermore, we found damaged cardiomyocytes in hamsters and COVID-19 autopsy samples. To explore the mechanism, we show that both human pluripotent stem cell-derived cardiomyocytes (hPSC-derived CMs) and adult cardiomyocytes (CMs) can be productively infected by SARS-CoV-2, leading to secretion of the monocyte chemoattractant cytokine CCL2 and subsequent monocyte recruitment. Increased CCL2 expression and monocyte infiltration was also observed in the hearts of infected hamsters. Although infected CMs suffer damage, we find that the presence of macrophages significantly reduces SARS-CoV-2-infected CMs. Overall, our study provides direct evidence that SARS-CoV-2 infects CMs in vivo and suggests a mechanism of immune cell infiltration and histopathology in heart tissues of COVID-19 patients.

Coxsackievirus A2 Leads to Heart Injury in a Neonatal Mouse Model.

Coxsackievirus A2 (CVA2) has emerged as an active pathogen that has been implicated in hand, foot, and mouth disease (HFMD) and herpangina outbreaks worldwide. It has been reported that severe cases with CVA2 infection develop into heart injury, which may be one of the causes of death. However, the mechanisms of CVA2-induced heart injury have not been well understood. In this study, we used a neonatal mouse model of CVA2 to investigate the possible mechanisms of heart injury. We detected CVA2 replication and apoptosis in heart tissues from infected mice. The activity of total aspartate transaminase (AST) and lactate dehydrogenase (LDH) was notably increased in heart tissues from infected mice. CVA2 infection also led to the disruption of cell-matrix interactions in heart tissues, including the increases of matrix metalloproteinase (MMP)3, MMP8, MMP9, connective tissue growth factor (CTGF) and tissue inhibitors of metalloproteinases (TIMP)4. Infiltrating leukocytes (CD45+ and CD11b+ cells) were observed in heart tissues of infected mice. Correspondingly, the expression levels of inflammatory cytokines in tissue lysates of hearts, including tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1ß), IL6 and monocyte chemoattractant protein-1 (MCP-1) were significantly elevated in CVA2 infected mice. Inflammatory signal pathways in heart tissues, including phosphatidylinositol 3-kinase (PI3K)-AKT, mitogen-activated protein kinases (MAPK) and nuclear factor kappa B (NF-κB), were also activated after infection. In summary, CVA2 infection leads to heart injury in a neonatal mouse model, which might be related to viral replication, increased expression levels of MMP-related enzymes and excessive inflammatory responses.

Hypertension as a sequela in patients of SARS-CoV-2 infection.

BACKGROUND: COVID-19 is a respiratory infectious disease caused by SARS-CoV-2, and cardiovascular damage is commonly observed in affected patients. We sought to investigate the effect of SARS-CoV-2 infection on cardiac injury and hypertension during the current coronavirus pandemic. STUDY DESIGN AND METHODS: The clinical data of 366 hospitalized COVID-19-confirmed patients were analyzed. The clinical signs and laboratory findings were extracted from electronic medical records. Two independent, experienced clinicians reviewed and analyzed the data. RESULTS: Cardiac injury was found in 11.19% (30/268) of enrolled patients. 93.33% (28/30) of cardiac injury cases were in the severe group. The laboratory findings indicated that white blood cells, neutrophils, procalcitonin, C-reactive protein, lactate, and lactic dehydrogenase were positively associated with cardiac injury marker. Compared with healthy controls, the 190 patients without prior hypertension have higher AngⅡ level, of which 16 (8.42%) patients had a rise in blood pressure to the diagnostic criteria of hypertension during hospitalization, with a significantly increased level of the cTnI, procalcitonin, angiotensin-II (AngⅡ) than those normal blood pressure ones. Multivariate analysis indicated that elevated age, cTnI, the history of hypertension, and diabetes were independent predictors for illness severity. The predictive model, based on the four parameters and gender, has a good ability to identify the clinical severity of COVID-19 in hospitalized patients (area under the curve: 0.932, sensitivity: 98.67%, specificity: 75.68%). CONCLUSION: Hypertension, sometimes accompanied by elevated cTnI, may occur in COVID-19 patients and become a sequela. Enhancing Ang II signaling, driven by SARS-CoV-2 infection, might play an important role in the renin-angiotensin system, and consequently lead to the development of hypertension in COVID-19.

ACE2 as a Key Target for Treatment of COVID-19 Related Cardiovascular Diseases: Current Progress and Prospect.

ACE2 has long been known as an injury protective protein, which can protect against a variety of organ damage such as the heart, liver, kidney, and lung. Especially in cardiovascular diseases, as a negative regulator of RAAS, ACE2 is an extremely important protective factor that mainly plays a role by converting Ang II to Ang-(1-7). Nevertheless, with the recent outbreak of COVID-19, it is exposed that another identity of ACE2 is the entry receptor for SARS-CoV-2, which previously serves as the entry receptor for SARS. With the in-depth clinical research, it is found that the severity and susceptibility of COVID-19 are related to cardiovascular diseases, and SARS-CoV-2 binding to ACE2 receptor is also potentially associated with heart injury symptoms. Therefore, in this article, we mainly summarize the relationship between ACE2, COVID-19, and cardiovascular diseases/heart injury.

Association of coagulation dysfunction with cardiac injury among hospitalized patients with COVID-19.

Cardiac injury is a common complication of the coronavirus disease 2019 (COVID-19), and is associated with adverse clinical outcomes. In this study, we aimed to reveal the association of cardiac injury with coagulation dysfunction. We enrolled 181 consecutive patients who were hospitalized with COVID-19, and studied the clinical characteristics and outcome of these patients. Cardiac biomarkers high-sensitivity troponin I (hs-cTnI), myohemoglobin and creatine kinase-myocardial band (CK-MB) were assessed in all patients. The clinical outcomes were defined as hospital discharge or death. The median age of the study cohort was 55 (IQR, 46-65) years, and 102 (56.4%) were males. Forty-two of the 181 patients (23.2%) had cardiac injury. Old age, high leukocyte count, and high levels of aspartate transaminase (AST), D-dimer and serum ferritin were significantly associated with cardiac injury. Multivariate regression analysis revealed old age and elevated D-dimer levels as being strong risk predictors of in-hospital mortality. Interleukin 6 (IL6) levels were comparable in patients with or without cardiac injury. Serial observations of coagulation parameters demonstrated highly synchronous alterations of D-dimer along with progression to cardiac injury. Cardiac injury is a common complication of COVID-19 and is an independent risk factor for in-hospital mortality. Old age, high leukocyte count, and high levels of AST, D-dimer and serum ferritin are significantly associated with cardiac injury, whereas IL6 are not. Therefore, the pathogenesis of cardiac injury in COVID-19 may be primarily due to coagulation dysfunction along with microvascular injury.

Key factors leading to fatal outcomes in COVID-19 patients with cardiac injury.

Cardiac injury among patients with COVID-19 has been reported and is associated with a high risk of mortality, but cardiac injury may not be the leading factor related to death. The factors related to poor prognosis among COVID-19 patients with myocardial injury are still unclear. This study aimed to explore the potential key factors leading to in-hospital death among COVID-19 patients with cardiac injury. This retrospective single-center study was conducted at Renmin Hospital of Wuhan University, from January 20, 2020 to April 10, 2020, in Wuhan, China. All inpatients with confirmed COVID-19 (≥ 18 years old) and cardiac injury who had died or were discharged by April 10, 2020 were included. Demographic data and clinical and laboratory findings were collected and compared between survivors and nonsurvivors. We used univariable and multivariable logistic regression methods to explore the risk factors associated with mortality in COVID-19 patients with cardiac injury. A total of 173 COVID-19 patients with cardiac injury were included in this study, 86 were discharged and 87 died in the hospital. Multivariable regression showed increased odds of in-hospital death were associated with advanced age (odds ratio 1.12, 95% CI 1.05-1.18, per year increase; p < 0.001), coagulopathy (2.54, 1.26-5.12; p = 0·009), acute respiratory distress syndrome (16.56, 6.66-41.2; p < 0.001), and elevated hypersensitive troponin I (4.54, 1.79-11.48; p = 0.001). A high risk of in-hospital death was observed among COVID-19 patients with cardiac injury in this study. The factors related to death include advanced age, coagulopathy, acute respiratory distress syndrome and elevated levels of hypersensitive troponin I.

Echocardiographic Features of Cardiac Injury Related to COVID-19 and Their Prognostic Value: A Systematic Review.

BACKGROUND: The available information on the echocardiographic features of cardiac injury related to the novel coronavirus disease 2019 (COVID-19) and their prognostic value are scattered in the different literature. Therefore, the aim of this study was to investigate the echocardiographic features of cardiac injury related to COVID-19 and their prognostic value. METHODS: Published studies were identified through searching PubMed, Embase (Elsevier), and Google scholar databases. The search was performed using the different combinations of the keywords "echocard*," "cardiac ultrasound," "TTE," "TEE," "transtho*," or "transeso*" with "COVID-19," "sars-COV-2," "novel corona, or "2019-nCOV." Two researchers independently screened the titles and abstracts and full texts of articles to identify studies that evaluated the echocardiographic features of cardiac injury related to COVID-19 and/or their prognostic values. RESULTS: Of 783 articles retrieved from the initial search, 11 (8 cohort and 3 cross-sectional studies) met our eligibility criteria. Rates of echocardiographic abnormalities in COVID-19 patients varied across different studies as follow: RV dilatation from 15.0% to 48.9%; RV dysfunction from 3.6% to 40%; and LV dysfunction 5.4% to 40.0%. Overall, the RV abnormalities were more common than LV abnormalities. The majority of the studies showed that there was a significant association between RV abnormalities and the severe forms and death of COVID-19. CONCLUSION: The available evidence suggests that RV dilatation and dysfunction may be the most prominent echocardiographic abnormality in symptomatic patients with COVID-19, especially in those with more severe or deteriorating forms of the disease. Also, RV dysfunction should be considered as a poor prognostic factor in COVID-19 patients.

Shock and Myocardial Injury in Children With Multisystem Inflammatory Syndrome Associated With SARS-CoV-2 Infection: What We Know. Case Series and Review of the Literature.

BACKGROUND: Multisystem inflammatory syndrome associated with SARS-CoV-2 infection can lead to myocardial injury and shock in children, likely the result of a severe inflammatory state, and can mimic Kawasaki disease. OBJECTIVE: To describe the characteristics of shock and myocardial injury in children with confirmed or suspeted COVID-19 during the SARS-CoV-2 pandemic in Spain, including clinical presentation, laboratory and imaging findings, treatment, disease course, and outcome. An extensive literature review is provided. METHODS: Retrospective case series including all children (age 1 month-18 years) admitted to a pediatric intensive care unit in Madrid, Spain, between March 15 and April 30, 2020 with suspected or confirmed SARS-CoV-2 infection and shock. RESULTS: Twelve previously healthy patients with shock, age 5 to 14 years, were included. All required volume resuscitation and 75% required vasoactive/inotropic support. Distributive shock was present on admission in 67% (n = 8), and 4 patients (33%) showed features of cardiogenic shock. Myocardial injury was diagnosed in 67% (n = 8) and ventricular dysfunction in 33% (n = 4). The most common symptoms on presentation were fever (100%), anorexia (100%), diarrhea (75%), and vomiting (75%). Five patients showed signs of Kawasaki disease but none met the criteria for the classic form. Laboratory findings revealed lymphopenia (83%), thrombocytopenia (83%), and increased inflammatory markers (100%). Respiratory status was not significantly impacted. Chest X-ray showed bilateral alveolar infiltrates in 7 (58%) and bilateral pneumonia in 3 (25%). COVID-19 was confirmed in 11 cases (92%). All received empirical therapy against COVID-19, thromboprophylaxis and immunomodulation. Median stay in the PICU and inpatient ward was 4.5 and 10 days, respectively. No patients died. CONCLUSION: Multisystem inflammatory syndrome in children with COVID-19 can mimic Kawasaki disease and lead to a combination of distributive and cardiogenic shock, probably secondary to a hyperinflammatory state that remains to be precisely defined. Treatment strategies include hemodynamic support, empirical therapies against COVID-19, thromboprophylaxis, and immunomodulation.

Over time relationship between platelet reactivity, myocardial injury and mortality in patients with SARS-CoV-2-associated respiratory failure.

The aim of this study (NCT04343053) is to investigate the relationship between platelet activation, myocardial injury, and mortality in patients affected by Coronavirus disease 2019 (COVID-19). Fifty-four patients with respiratory failure due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were enrolled as cases. Eleven patients with the same clinical presentation, but negative for SARS-CoV-2 infection, were included as controls. Blood samples were collected at three different time points (inclusion [T1], after 7 ± 2 days [T2] and 14 ± 2 days [T3]). Platelet aggregation by light transmittance aggregometry and the circulating levels of soluble CD40 ligand (sCD40L) and P-selectin were measured. Platelet biomarkers did not differ between cases and controls, except for sCD40L which was higher in COVID-19 patients (p = .003). In COVID-19 patients, P-selectin and sCD40L levels decreased from T1 to T3 and were higher in cases requiring admission to intensive care unit (p = .004 and p = .008, respectively). Patients with myocardial injury (37%), as well as those who died (30%), had higher values of all biomarkers of platelet activation (p < .05 for all). Myocardial injury was an independent predictor of mortality. In COVID-19 patients admitted to hospital for respiratory failure, heightened platelet activation is associated with severity of illness, myocardial injury, and mortality.ClinicalTrials.gov number: NCT04343053.

Cardiac injury and mortality in patients with Coronavirus disease 2019 (COVID-19): insights from a mediation analysis.

BACKGROUNDS: Patients at greatest risk of severe clinical conditions from coronavirus disease 2019 (COVID-19) and death are elderly and comorbid patients. Increased levels of cardiac troponins identify patients with poor outcome. The present study aimed to describe the clinical characteristics and outcomes of a cohort of Italian inpatients, admitted to a medical COVID-19 Unit, and to investigate the relative role of cardiac injury on in-hospital mortality. METHODS AND RESULTS: We analyzed all consecutive patients with laboratory-confirmed COVID-19 referred to our dedicated medical Unit between February 26th and March 31st 2020. Patients' clinical data including comorbidities, laboratory values, and outcomes were collected. Predictors of in-hospital mortality were investigated. A mediation analysis was performed to identify the potential mediators in the relationship between cardiac injury and mortality. A total of 109 COVID-19 inpatients (female 36%, median age 71 years) were included. During in-hospital stay, 20 patients (18%) died and, compared with survivors, these patients were older, had more comorbidities defined by Charlson comorbidity index ≥ 3(65% vs 24%, p = 0.001), and higher levels of high-sensitivity cardiac troponin I (Hs-cTnI), both at first evaluation and peak levels. A dose-response curve between Hs-cTnI and in-hospital mortality risk up to 200 ng/L was detected. Hs-cTnI, chronic kidney disease, and chronic coronary artery disease mediated most of the risk of in-hospital death, with Hs-cTnI mediating 25% of such effect. Smaller effects were observed for age, lactic dehydrogenase, and D-dimer. CONCLUSIONS: In this cohort of elderly and comorbid COVID-19 patients, elevated Hs-cTnI levels were the most important and independent mediators of in-hospital mortality.

Is it all in the heart? Myocardial injury as major predictor of mortality among hospitalized COVID-19 patients.

Coronavirus disease 2019 (COVID-19) is an infection caused by the virus SARS-CoV-2, and has caused the most widespread global pandemic in over 100 years. Given the novelty of the disease, risk factors of mortality and adverse outcomes in hospitalized patients remain to be elucidated. We present the results of a retrospective cohort study including patients admitted to a large tertiary-care, academic university hospital with COVID-19. Patients were admitted with confirmed diagnosis of COVID-19 between 1 March and 15 April 2020. Baseline clinical characteristics and admission laboratory variables were retrospectively collected. Patients were grouped based on mortality, need for ICU care, and mechanical ventilation. Prevalence of clinical co-morbidities and laboratory abnormalities were compared between groups using descriptive statistics. Univariate analysis was performed to identify predictors of mortality, ICU care and mechanical ventilation. Predictors significant at P ≤ .10 were included in multivariate analysis. Five hundred and sixty patients were included in the analysis. Age and myocardial injury were only independent predictors of mortality, in patients with/without baseline co-morbidities. Body mass index, elevated ferritin, elevated d-dimer, and elevated procalcitonin predicted need for ICU care, and these along with vascular disease at baseline predicted need for mechanical ventilation. Hence, inflammatory markers (ferritin and d-dimer) predicted severe disease, but not death.

Single-cell RNA analysis on ACE2 expression provides insights into SARS-CoV-2 potential entry into the bloodstream and heart injury.

Coronavirus disease-2019 (COVID-19) is a global pandemic with high infectivity and pathogenicity, accounting for tens of thousands of deaths worldwide. Recent studies have found that the pathogen of COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), shares the same cell receptor angiotensin converting enzyme II (ACE2) as SARS-CoV. The pathological investigation of COVID-19 deaths showed that the lungs had characteristics of pulmonary fibrosis. However, how SARS-CoV-2 spreads from the lungs to other organs has not yet been determined. Here, we performed an unbiased evaluation of cell-type-specific expression of ACE2 in healthy and fibrotic lungs, as well as in normal and failed adult human hearts, using published single-cell RNA-seq data. We found that ACE2 expression in fibrotic lungs mainly locates in arterial vascular cells, which might provide a route for bloodstream spreading of SARS-CoV-2. Failed human hearts have a higher percentage of ACE2-expressing cardiomyocytes, and SARS-CoV-2 might attack cardiomyocytes through the bloodstream in patients with heart failure. Moreover, ACE2 was highly expressed in cells infected by respiratory syncytial virus or Middle East respiratory syndrome coronavirus and in mice treated by lipopolysaccharide. Our findings indicate that patients with pulmonary fibrosis, heart failure, and virus infection have a higher risk and are more susceptible to SARS-CoV-2 infection. The SARS-CoV-2 might attack other organs by getting into the bloodstream. This study provides new insights into SARS-CoV-2 blood entry and heart injury and might propose a therapeutic strategy to prevent patients from developing severe complications.

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

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

Association of cardiac biomarkers and comorbidities with increased mortality, severity, and cardiac injury in COVID-19 patients: A meta-regression and decision tree analysis.

BACKGROUND: Coronavirus disease-2019 (COVID-19) has a deleterious effect on several systems, including the cardiovascular system. We aim to systematically explore the association of COVID-19 severity and mortality rate with the history of cardiovascular diseases and/or other comorbidities and cardiac injury laboratory markers. METHODS: The standardized mean difference (SMD) or odds ratio (OR) and 95% confidence intervals (CIs) were applied to estimate pooled results from the 56 studies. The prognostic performance of cardiac markers for predicting adverse outcomes and to select the best cutoff threshold was estimated by receiver operating characteristic curve analysis. Decision tree analysis by combining cardiac markers with demographic and clinical features was applied to predict mortality and severity in patients with COVID-19. RESULTS: A meta-analysis of 17 794 patients showed patients with high cardiac troponin I (OR = 5.22, 95% CI = 3.73-7.31, P < .001) and aspartate aminotransferase (AST) levels (OR = 3.64, 95% CI = 2.84-4.66, P < .001) were more likely to develop adverse outcomes. High troponin I more than 13.75 ng/L combined with either advanced age more than 60 years or elevated AST level more than 27.72 U/L was the best model to predict poor outcomes. CONCLUSIONS: COVID-19 severity and mortality are complicated by myocardial injury. Assessment of cardiac injury biomarkers may improve the identification of those patients at the highest risk and potentially lead to improved therapeutic approaches.

Association Between Cardiac Injury and Mortality in Hospitalized Patients Infected With Avian Influenza A (H7N9) Virus.

OBJECTIVES: To evaluate the prevalence of cardiac injury and its association with mortality in hospitalized patients infected with avian influenza A (H7N9) virus. DESIGN: Retrospective cohort study. SETTING: A total of 133 hospitals in 17 provinces, autonomous regions, and municipalities of mainland China that admitted influenza A (H7N9) virus-infected patients between January 22, 2015, and June 16, 2017. PATIENTS: A total of 321 patients with influenza A (H7N9) virus infection were included in the final analysis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Demographics and clinical characteristics were collected from medical records. Cardiac injury was defined according to cardiac biomarkers, electrocardiography, or echocardiography. Among the 321 patients, 203 (63.2%) showed evidence of cardiac injury. Compared with the uninjured group, the cardiac injury group had lower PaO2/FIO2 (median, 102.0 vs 148.4 mm Hg; p < 0.001), higher Acute Physiology and Chronic Health Evaluation II score (median, 17.0 vs 11.0; p < 0.001), longer stay in the ICU (10.0 vs 9.0 d; p = 0.029), and higher proportion of in-hospital death (64.0% vs 20.3%; p < 0.001). The proportion of virus clearance until discharge or death was lower in the cardiac injury group than in the uninjured group (58.6% vs 86.4%; p < 0.001). Multivariable-adjusted Cox proportional hazards regression analysis showed that cardiac injury was associated with higher mortality (hazards ratio, 2.06; 95% CI, 1.31-3.24) during hospitalization. CONCLUSIONS: Cardiac injury is a frequent condition among hospitalized patients infected with influenza A (H7N9) virus, and it is associated with higher risk of mortality.

Myocardial injury and bacterial pneumonia contribute to the pathogenesis of fatal influenza B virus infection.

BACKGROUND: Influenza B virus infection causes rates of hospitalization and influenza-associated pneumonia similar to seasonal influenza A virus infection and accounts for a substantial percentage of all influenza-related hospitalizations and deaths among those aged <18 years; however, the pathogenesis of fatal influenza B virus infection is poorly described. METHODS: Tissue samples obtained at autopsy from 45 case patients with fatal influenza B virus infection were evaluated by light microscopy and immunohistochemical assays for influenza B virus, various bacterial pathogens, and complement components C4d and C9, to identify the cellular tropism of influenza B virus, characterize concomitant bacterial pneumonia, and describe the spectrum of cardiopulmonary injury. RESULTS: Viral antigens were localized to ciliated respiratory epithelium and cells of submucosal glands and ducts. Concomitant bacterial pneumonia, caused predominantly by Staphylococcus aureus, was identified in 38% of case patients and occurred with significantly greater frequency in those aged >18 years. Pathologic evidence of myocardial injury was identified in 69% of case patients for whom cardiac tissue samples were available for examination, predominantly in case patients aged <18 years. CONCLUSIONS: Our findings suggest that bacterial pneumonia and cardiac injury contribute to fatal outcomes after infection with influenza B virus and that the frequency of these manifestations may be age related.