[The ESC recommendations for COVID-19-no guideline, but a learning guidance]

SARS-CoV-2, vaccination or autoimmunity as causes of cardiac inflammation. Which form prevails?

The causes of cardiac inflammation during the COVID-19 pandemic are manifold and complex, and may have changed with different virus variants and vaccinations. The underlying viral etiology is self-evident, but its role in the pathogenic process is diverse. The view of many pathologists that myocyte necrosis and cellular infiltrates are indispensable for myocarditis does not suffice and contradicts the clinical criteria of myocarditis, i.e., a combination of serological evidence of necrosis based on troponins or MRI features of necrosis, edema, and inflammation based on prolonged T1 and T2 times and late gadolinium enhancement. The definition of myocarditis is still debated by pathologists and clinicians. We have learned that myocarditis and pericarditis can be induced by the virus via different pathways of action such as direct viral damage to the myocardium through the ACE2 receptor. Indirect damage occurs via immunological effector organs such as the innate immune system by macrophages and cytokines, and then later the acquired immune system via T cells, overactive proinflammatory cytokines, and cardiac autoantibodies. Cardiovascular diseases lead to more severe courses of SARS-CoV‑2 disease. Thus, heart failure patients have a double risk for complicated courses and lethal outcome. So do patients with diabetes, hypertension, and renal insufficiency. Independent of the definition, myocarditis patients benefitted from intensive hospital care, ventilation, if needed, and cortisone treatment. Postvaccination myocarditis and pericarditis affect primarily young male patients after the second RNA vaccine. Both are rare events but severe enough to deserve our full attention, because treatment according to current guidelines is available and necessary.

[2 years COVID-19 pandemic-What have we learned?]

After 2 years and 5 waves of the coronavirus disease 2019 (COVID-19) pandemic in Germany and experience with superspreader events worldwide, we know that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a rapidly mutating virus with changing clinical phenotypes. Besides infections of the respiratory tract, which in severe cases are accompanied by pneumonia requiring mechanical ventilation, the involvement of the heart with myocarditis and pericarditis as well as the kidneys have short-term and also long-term consequences. We have learnt to deal with myocarditis and pericarditis in acute infections and after vaccinations, which in rare cases can also lead to myocarditis and pericarditis. Myocarditis with myocytolysis in autopsy specimens or endomyocardial biopsy specimens is rare. In contrast, elevated troponin levels and suspicious cardiac magnetic resonance imaging (MRI) findings are much more frequent. The best preventive measure is a complete double basic vaccination and booster vaccination with an mRNA vaccine. For patients and medical personnel precise information is given with respect to personal protective equipment and behavior (distancing-hygiene-mask-airing rule).