Rationale for endomyocardial biopsy in the diagnosis of heart disease in children and adults

Endomyocardial biopsy (EMB) is the method of choice for diagnosing a wide range of myocardial diseases. Aim . To assess the rationale for diagnostic EMB in children and adults. Material and methods . Morphological and statistical analysis of 2803 diagnostic EMBs in adults (n=811) and children (n=83), including those in heart transplantation (n=1909), was carried out. Results . In 231 (28%) cases, adults were diagnosed with myocarditis, of which in 6 patients — granulomatous, in 5 — eosinophilic and in 6 — lymphocytic-macrophage myocarditis after coronavirus infection. In children, myocarditis was found in 22 cases (27%). Arrhythmogenic right ventricular dysplasia took the second place in detection rate in children and adults. Immunohistochemical study revealed viral envelope protein 1 (VP1) antigen of enteroviruses in one third of myocarditis cases, and in half — other cardiotropic viruses. Dotted dystrophin expression was observed in myocarditis. A correlation was established between the perforin expression and myocarditis presence (Pearson χ 2 =27,8; Fisher's exact test=27,3; p=0,01). Conclusion . Analysis of diagnostic EMB results confirmed its rationale in adults and children not only for heart transplantation, but also for identifying cardiac pathology, including for myocarditis diagnosis. It has been shown that immunohistochemical study with antiviral antibodies can be considered as an alternative method for detecting viral infection. An immunohistochemical analysis for perforin and dystrophin can be recommended as additional morphological markers of myocarditis.