Objective Fibrosis in atrial myocardium is a common phenomenon for patients with atrial fibrillation. Remodeling of connexins and enlargement of left atrium was found accompanying with atrial fibrillation as well, The aim of the study is: 1.to investigate whether it is by causing the remodeling of connexin 43(Cx43) that the fibrosis of atrial muscle plays an important role during the initiation and maintenance of atrial fibrillation. 2.to reveal the differences of remodelling of typeⅠCollagen in atri...