Therefore, beyond the general approach to distinguish between patients with or without risk of severe illness from COVID-19, some studies have focused on certain complications derived from the disease, such as the appearance of atrioventricular block (AVB), in which several differentially expressed proteins in plasma were identified (serum amyloid A protein, tetranectin, and neutrophil defensin 3) [69] or cases of secondary hemorrhagic lymphohistiocytosis (sHLH), a hyperinflammatory disorder related to the aforementioned cytokine storm which can complicate infectious processes. This evidence concerns the gene SAA1 and atrioventricular block.