To assess whether enhanced ERK MAPK activity was required for ECM remodeling triggered by TGFβ or high concentration LY2109761, 3D cultures derived from AF were exposed to TGFβ or 20 μM LY2109761 in absence or presence of a PD0325901 MEKi (Mirdametinib). This evidence concerns the gene TGFB1 and atrial fibrillation.