P4HB and atrial fibrillation: Protein disulfide isomerase (PDI), eukaryotic elongation factor 1 alpha (eEF1A) and prolyl cis-trans isomerase (PIN1) showed decreased expression in the serum EV of AF patients, indicating an imbalance in protein regulation, potential protein misfolding and oxidative stress, thus offering insights into AF pathogenesis (49).