Neutrophil Infiltration Induces Myocardial Injury In COVID-19 Post-Mortem Cases

Abstract Objectives: The pathological features of severe cardiac injury induced by COVID-19 and relevant clinical features is unknown.Methods: This autopsy cohort study, including hearts from 26 deceased patients hospitalized in intensive care unit due to COVID-19, was conducted at four sites in Wuhan, China. Cases were divided into neutrophil-infiltration group and no-neutrophil group according to histopathological identification of neutrophilic infiltrates or not.Results: Among 26 cases, four cases had active myocarditis with histopathological examination. All cases with myocarditis accompanied with extensive neutrophil infiltration, while cases without myocarditis did not. Detection rates of interleukin-6 (100% vs 4.6%) and tumor necrosis factor-a (100% vs 31.8%) in neutrophil-infiltration group were significantly higher compared to no-neutrophil group (p<0.05 for both). At admission, patients with neutrophil infiltration in myocardium had significantly higher baseline values of aspartate aminotransferase, D dimer and high-sensitivity C reactive protein compared to other 22 patients (p<0.05 for all). During hospitalization, patients with neutrophil infiltration had a significantly higher maximum of creatine kinase (CK)-MB (median 280.0 vs 38.7IU/L, p=0.04), and a quantitatively higher top Troponin I (median 1.112 vs 0.220ng/ml, p=0.56) than patients without neutrophil infiltration. Conclusions: In hearts from deceased patients with severe COVID-19, active myocarditis was commonly infiltrated with neutrophils. Cases with neutrophil-infiltrated myocarditis had a series of severe abnormal laboratory tests at admission, and a high maximum of CK-MB during hospitalization. Role of neutrophil on severe heart injury and even systemic condition in COVID-19 should be emphasized.