SARS-CoV-2 induced myocarditis as a cause of acute decompensation in a patient with familial cardiomyopathy and a pathogenic variant in the titin gene

Myocarditis is an infl ammatory disease, one of the most common non-coronary myocardial diseases. During the COVID-19 pandemic, SARS-CoV-2-associated myocarditis has attracted particular interest from the cardiology community. Acute myocardial damage caused by SARS-CoV-2 is based on diff erent mechanisms. At the same time, the nature of the body’s response to various infections, including viral and, in particular, coronavirus, is individual and is largely determined genetically. We present a description of a clinical observation that shows the signifi cance of myocarditis joining a previously asymptomatic genetically determined myocardial damage. A 62-year-old female patient was admitted to the clinic due to shortness of breath with minimal physical exertion and at rest, dilation of the heart chambers, a drop in the ejection fraction (EF) of the left ventricular (LV) myocardium to 25%, and bilateral hydrothorax. Throughout her life, she tolerated stress well and maintained good physical fi tness until the sudden development of biventricular heart failure. The sudden death of her father at the age of 62 and the diagnosis of dilated cardiomyopathy (DCM) in her twin brother could indicate the presence of a genetically determined form of DCM. Myocardial infarction was excluded as a cause of acute decompensation; the later diagnosed thromboembolism of small branches of the pulmonary artery (PE) did not explain the full severity of the myocardial damage. The acute development of myocardial dysfunction in the absence of atrial fi brillation made the diagnosis of myocarditis no less likely, which was subsequently confi rmed morphologically, as well as its coronavirus nature. A month after the start of complex cardiotropic therapy, its ineff ectiveness was established (refractory critical heart failure), which required immediate heart transplantation, for which the patient was transferred to the Federal Scientifi c Center of Therapy and Orthopedics named after N.N. Acad. V. I. Shumakova. A week later, while waiting for a transplant, ventricular fi brillation and circulatory arrest developed. Resuscitation measures were ineff ective, the patient was declared dead. DNA diagnostics, completed after death, revealed a likely pathogenic variant in the titin gene and a variant with unknown clinical signifi cance in the myopalladin gene. Cases of morphologically verifi ed post-COVID myocarditis in patients with titinopathy have not been previously described in the literature. This observation clearly illustrates the insuffi cient information content of all noninvasive methods for diagnosing myocarditis, including magnetic resonance imaging (MRI) of the heart with contrast. In a situation where the patient initially had indications for a heart transplant, an attempt at active immunosuppressive therapy for the identifi ed myocarditis was justifi ed, but it had no eff ect, as did the maximum tolerated cardiotropic therapy. It is highly probable that it was the initial genetic inferiority of the myocardium that predetermined the severe course of myocarditis and the unfavorable outcome of the disease as a whole. In this clinical case, the combination of primary (familial) DCM and morphologically confi rmed SARS-CoV-2-induced lymphocytic myocarditis is of particular interest. Diagnosis and treatment of non-coronary myocardial diseases still pose signifi cant diffi  culties. The insuffi  ciently studied combination of myocarditis and primary cardiomyopathies may be the reason for the ineff ectiveness of conservative therapy, and heart transplantation remains the only way to save patients. Despite the unfavorable outcome of the disease, this observation demonstrates the need to use all available methods to identify the causes of DCM syndrome (not only MRI, but also myocardial biopsy and whole exome sequencing).

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