MMP3 and atrial fibrillation: There was no change in the relative gene expression of aggrecan or type I collagen in the nondegenerative AF cells following 1.0-Hz CTS as previously reported [18], while MMP3 and ADAMTS4 were significantly decreased at 1 hour post-mechanical stimulation (sixfold, P < 0.05, and sevenfold, P < 0.05, respectively) (Figures 2a and 2b).