The Role of Matrix Metalloproteinase-2 in the Treatment of Atrial Fibrillation Recurrence after a Radiofrequency Modified Maze Procedure

Background and Objective: Our study aimed to elucidate the potential clinical and molecular issues in recurrent atrial fibrillation (AF) following a radiofrequency modified maze procedure in patients with rheumatic valvular disease and persistent AF. Methods and Results: Eighty patients with rheumatic valvular disease and persistent AF (lasting more than 6 months) who had undergone a radiofrequency modified maze procedure and mitral valve replacement were enrolled into this single-center pilot study and were followed up for another 6 months. Their clinical characteristics were analyzed and the expression of matrix metalloproteinase (MMP)-2 including its specific inhibitor and collagen volume fraction (CVF) was also assessed. During the 6-month follow-up, 24 subjects had recurrent AF. Among them, the left atrial diameter was larger compared to that achieved in sinus rhythm (SR). The mRNA and protein expression of MMP-2 was significantly increased in recurrent AF patients, while its specific inhibitor did not show a significant difference (p > 0.05). The CVF of type I collagen increased significantly in the recurrent AF patients compared to SR patients (18.16 +/- 3.22 vs. 11.66 +/- 3.38, p < 0.001), whereas the CVF of type III collagen showed no significant difference (8.33 +/- 3.44 vs. 9.55 +/- 3.67, p > 0.05). Conclusion: This study suggests that the overexpression of MMP-2 is associated with CVF-I in the left atrial appendage which potentially leads to the recurrence of AF following a radiofrequency modified maze procedure in patients with rheumatic valve disease. Copyright (c) 2013 S. Karger AG, Basel