Changes in matrix metalloproteinase-9 levels during progression of atrial fibrillation

OBJECTIVES: To observe levels of matrix metalloproteinase (MMP)-9 and evaluate their significance in various stages of idiopathic atrial fibrillation (AF). METHODS: Patients with idiopathic AF were recruited into this prospective study and classified into one of three groups according to stage of disease progression: paroxysmal AF; persistent AF; permanent AF. Healthy individuals were enrolled as control subjects. Serum levels of MMP-9 in all four groups were determined using a double-antibody sandwich enzyme-linked immunosorbent assay. RESULTS: Each AF group included 25 patients; 40 healthy individuals were included as controls. MMP-9 levels in the three AF groups were significantly higher than in the control group: 168.72 ± 25.970, 201.36 ± 31.26 and 253.20 ± 22.99 ng/ml for the paroxysmal, persistent and permanent AF groups respectively, versus 76.80 ± 14.90 ng/ml for the control group. MMP-9 levels increased with idiopathic AF disease progression (P < 0.05). CONCLUSIONS: An elevated MMP-9 level appears to be associated with a diagnosis of AF. MMP-9 levels appear to increase in relation to the stage of idiopathic AF progression.