When and why to performing endomyocardial biopsy?

Abstract

Heart failure with reduced ejection fraction(HFrEF) is a condition that should always be taken seriously and the causes of myocardial damage should be identified as soon as possible. Very often in new reduced systolic function of the left ventricle (LV) may be myocarditis with for an unknown cause. The increased incidence of COVID-19 worldwide and the continued mutation of SARS-COV 2, regardless of vaccines, remain a major medical and social problem. The effect of the virus on the cardiovascular system and in particular to the manifestation of inflammatory damage to the myocardium has been proven. Despite the apparent positive effect of vaccines, cases of post-vaccination myocarditis have been reported, mainly in young people with mRNA vaccine, with reversible changes and non-fatal prognosis after early diagnosis and initiation of treatment. Apart from the viral genesis of myocarditis, the use of various drugs and toxic substances, the growing number of oncological diseases and the widespread use of chemotherapeutics also have a detrimental effect on the myocardium. Timely diagnosis and isolation of the causative agent are key to choosing the  accurate treatment. Endomyocardial biopsy (EMB) is one of the methods assessed as the "gold standard", with still underestimated place in its diagnosis of a variety of diseases. Despite the proven benefits and recommendations for the study of myocarditis, anthracycline-induced cardiotoxicity, specific heart diseases such as endomyocardial fibrosis and Löffler's endocarditis, scleroderma, idiopathic chest pain and arrhythmias,differential diagnosis of restrictive vs constrictive diseases, this relatively easy and safe invasive approach remains low in frequency. Imposing EMB as a routine method in centers with the ability to conduct and interpret the results is especially important for the proper treatment of many cardiovascular diseases, many of which often remain unrecognized in the daily routine. We present a clinical case of a patient with newly diagnosed HFrEF, who was  with myocarditis, proven histologically after EMB. Due to the timing of the second dose of mRNA vaccine against COVID-19 and the manifestation of symptoms with newly diagnosed dilated cardiomyopathy, in the absence of isolated viral agent and lack of autoimmune disease, circulating high titer of antibodies against SARS-COV 2, we accepted the thesis of postvaccinal myocardial damage.