MEF2C and miotic rate: The expressions of mRNAs of PPP3CB (MR, n = 13, normal subjects, n = 6; 14.45±0.35 vs. 16.02±0.19, P = 0.007) and MEF2C (MR, n = 14, normal subjects, n = 5; 15.67±0.56 vs. 17.82±0.36, P = 0.021) in the left atrial free wall were significantly up-regulated in the MR patients compared to normal subjects (Fig 5).