Myeloperoxidase (MPO), a peroxidase enzyme released from neutrophil granulocytes16, had the most significant change in abundance and was increased 9.2-fold in AF, while myosin heavy chain 10 (MYH10, also known as non-muscle myosin IIB) was most significantly decreased in AF (Supplementary Table 1). Here, MPO is linked to atrial fibrillation.