Consistent with our functional data showing decreased contractility, terms associated with heart contraction such as cardiac cell development, regulation of heart contraction, cardiac muscle cell differentiation, myofibril assembly, and ion transport were amongst the significantly downregulated pathways with expression of genes encoding for sarcomeric proteins such as MYH7 and TNNI3, key cardiac transcription factors such as NKX2.5 and HEY2 and ion channels such as SCN5A and SLC8A1 being significantly decreased in most of the samples treated with the severe COVID-19 sera (Figure 5D and E). Here, HEY2 is linked to COVID-19.