KRT8 and atrial fibrillation: By day 28, a decrease in Krt8 expression within the NP indicated phenotypic integrity loss, while the increased concurrent expression of the degenerative marker Chi3l164, 65 in the AF and Mmp366, 67, 68 in the NP further corroborated this degenerative process, enabling identification of Degenerated AF and Degenerated NP zone, respectively (Figure 6B).