Relation between myoglobin and cardiac dysfunction in myocarditis--immunohistochemical study of endomyocardial biopsy specimens

Myoglobin for Detection of High-Risk Patients with Acute Myocarditis

There is an unmet need for accurate and practical screening to detect myocarditis. We sought to test the hypothesis that the extent of acute myocarditis, measured by late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR), can be estimated based on routine blood markers. A total of 44 patients were diagnosed with acute myocarditis and included in this study. There was strong correlation between myoglobin and LGE (r_s = 0.73 [95% CI 0.51; 0.87], p < 0.001), while correlation was weak between LGE and TnT-hs (r_s = 0.37 [95% CI 0.09; 0.61], p = 0.01). Receiver operating curve (ROC) analysis determined myoglobin ≥ 87 μg/L as cutoff to identify myocarditis (92% sensitivity, 80% specificity). The data were reproduced in an established model of coxsackievirus B3 myocarditis in mice (n = 26). These data suggest that myoglobin is an accurate marker of acute myocarditis. Graphical Abstract Receiver operating curve analysis determined myoglobin ≥ 87 μg/L as cutoff to identify myocarditis and these data were reproduced in an established model of coxsackievirus B3 myocarditis in mice: CMRI, cardiac magnetic resonance imaging; Mb, myoglobin; LGE, late gadolinium enhancement; ROC, receiver operating curve analysis.

National survey of the use of endomyocardial biopsy in Japan

A national survey of endomyocardial biopsy procedures was conducted in Japan. Questionnaires were mailed to 852 institutions and statistical analysis of the 213 completed questionnaires (25.0% of the total) was performed. Cardiac biopsies were being performed at 134 of these institutions (62.9%), representing a 5.5-fold increase over 1980. A total of 19,964 cardiac biopsies have been performed in Japan. Specimens were obtained from the right ventricle at 113 institutions, and from the left ventricle at 76 centers. The Konno-Sakakibara bioptome was used at 32 institutions, whereas the long sheath method was used at 98 institutions. Sixty of the institutions (44.8%) had encountered ventricular wall perforation. The perforation rate of the two ventricles combined was 0.7% (147 of 19,964 cases), with a mortality rate of 0.05% (10 of 19,964 cases). Endomyocardial biopsy has become widespread in Japan, and its safety was ascertained by this national survey.