ABCB1 and atrial fibrillation: Multiple linear regression analysis was aimed to analyze influence of the basic clinical, biochemical parameters, polymorphisms of rs4148738, rs1045642, rs2032582 and rs1128503 in the ABCB1 gene and rs8192935, rs2244613, rs71647871 in the CES1 gene to the peak and trough plasma concentration level of dabigatran/apixaban in AF patients.