In the bioptates of right atrium appendages (RAA) and right atrium free walls (RWF) achieved intraoperatively during mini-Maze procedure in patients with persistent AF and patients with SR, in all samples collected from patients with AF, MMP-2, MMP-9 and TIMP-2 levels were significantly elevated in comparison with patients with SR. Here, MMP2 is linked to atrial fibrillation.