Cardiac tamponade - an unexpected "long COVID-19" complication.

Introduction: Year 2020 has been a cornerstone in medical research due to the COVID-19 pandemic outbreak. The process of understanding the condition brought to light certain organ involvement like pulmonary or kidney damage or endocrine disbalances, while connection to other types of organ impairment remain unclear. SARS-CoV-2 has previously been incriminated in cardiac involvement, ranging from mild symptoms to more severe occurrences such as myocarditis, arrythmias or heart failure, thus complicating the acute-phase management and worsening patients' prognosis. Despite being reported as an acute manifestation in critical COVID-19, cardiac tamponade seems to also occur as a "long- COVID19" complication. The latter is a distinct yet unclear entity associated with remanent fatigue or cough, but more severe sequelae like vasculitis or polyneuropathy can occsur.

Case Report: We report the case of a 42-year-old patient admitted in the intensive care unit for severe respiratory and renal dysfunction one month after an initial mild episode of COVID-19. RT-PCR for SARS-CoV-2 on admission was negative. Initial imaging through CT and heart ultrasound revealed the presence of pericardial effusion but no signs of tamponade were initially obvious. Twelve hours later, the patient's state deteriorated with cardiocirculatory failure and signs of obstructive shock. Agents responsible for severe acute respiratory infection (SARI) such as influenza A and B, adenovirus, , , coxsackie virus, or parainfluenza viruses were ruled out. Surprisingly, RT-PCR testing for SARS-CoV-2 came back positive, although the initial test was negative. Repeated imaging confirmed massive circumferential pericardial effusion for which emergency pericardiocentesis was performed. Fluid was an exudate and histopathology reported chronic inflammation. RT-PCR testing for in the pericardial tissue came back negative.

Conclusions: The case is to our knowledge among the first to report cardiac tamponade one month after mild COVID-19 infection. The aim of this case report is to raise awareness in the medical community on the possibility of severe complications targeting major organs in the long-COVID-19 phase.