RNA-seq profiling of left atrial remodeling in a minimally invasive echocardiography-guided mouse model of degenerative mitral regurgitation

Degenerative mitral regurgitation (MR) leads to progressive atrial enlargement, fibrosis, calcium-handling abnormalities, and arrhythmogenesis. To investigate transcriptomic remodeling associated with MR, we established a minimally invasive, transthoracic echocardiography-guided mouse model by puncturing the anterior mitral leaflet through a closed-chest apical approach. Left atrial (LA) tissues were harvested two weeks after MR induction from adult C57BL/6J mice and compared with sham-operated controls. Bulk RNA sequencing was performed to characterize molecular pathways associated with atrial remodeling and arrhythmogenic remodeling. Transcriptomic analysis revealed enrichment of calcium signaling, apoptosis, extracellular matrix remodeling, and shear stress–related pathways in MR atria, consistent with structural remodeling, fibrosis, and enhanced arrhythmogenic susceptibility observed in functional and histological assessments. This dataset provides a reproducible murine transcriptomic resource for studying atrial remodeling and calcium-handling dysregulation in valvular heart disease.