TIMP1 and atrial fibrillation: Elite athletes may present higher levels of profibrotic markers which have been associated with incident or recurrent AF in the general population [66,67,68], including galectin-3 [69], the suppression of tumorigenicity 2 (ST2) [70], and microRNA-21 (miR-21) [71], as well as tissue inhibitors of metalloproteinase 1 (TIMP-1), C-terminal telopeptide of type I collagen (CITP), and procollagen type I carboxy-terminal propeptide (PICP) [53].