Subsequently, ChIP assay was implemented to detect the H3K9me2 and H3K4me3 enrichment in IGFBP3 promoter region in clinical tissues and cell models, and the results revealed an increased H3K9me2 enrichment and a reduced H3K4me3 enrichment in AF patients, and the trend of ChIP results was the same in the cell model (Fig. 4D, E). This evidence concerns the gene IGFBP3 and atrial fibrillation.