TGFβ1 expression activated atrial fibroblasts to become MFbs, which then expressed α‐SMA and secreted type I collagen in large amounts, promoting atrial fibrosis in AF patients.22 In this work, RT‐PCR results showed that the relative CTGF mRNA levels in MFbs of CAF patients increased significantly. The gene discussed is TGFB1; the disease is atrial fibrillation.