The clinical significance of the atrial subendocardial smooth muscle layer and cardiac myofibroblasts in human atrial tissue with valvular atrial fibrillation

SSM layer was closely related to the existence of AF, degrees of atrial remodeling, and fibrosis in patients who underwent open heart surgery. We found that MFB does exist in SSM layer of human atrial tissue co-localized with PAS-positive cells.