CD8A and atrial fibrillation: We found increased infiltration of activated CD4 T cell, activated CD8 T cell, activated dendritic cell, gamma delta T cell, immature B cell, MDSC, macrophage, mast cell, monocyte, neutrophil, plasmacytoid dendritic cell, regulatory T cell, type 17 T helper cell, effector memory CD4 T cell, central memory CD4 T cell, central memory CD8 T cell, and effector memory CD8 T cell in AF.