Myocardial fibrosis plays a key role in the occurrence and development of atrial structural remodeling and is a common pathological feature of cardiovascular diseases, such as hypertensive heart disease, myocardial infarction, heart failure, etc. Fang et al. [47] found that relatively stable circulating miR-15a was upregulated in diffuse myocardial fibrosis and affected cardiac-disease-related pathways, such as apoptosis, MAPK signaling, TGF-β, and other cytokine signaling pathways, meaning that it could be used as a biomarker and therapeutic target for the diagnosis of myocardial fibrosis. Here, TGFB1 is linked to heart failure.