SDC1 and atrial fibrillation: AF patients had significantly elevated levels of SDC-1 mRNA (2.12 ± 0.13, n = 6 vs. 1.074 ± 0.18, n = 6 in ctrl) (Figure 6A) and protein expression (0.91 ± 0.07, n = 3 vs. 0.42 ± 0.04, n = 3 in ctrl) (Figure 6B).