Relationship Of Type I Collagen, Connectin43 And Enlargement Of Left Atrium In The Patients With Or Without Atrial Fibrillation

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 typeâ… Collagen in atrial myocardium and left atrium size in patients with valvular heart disease with or without persistant atrial fibrillation.Methods 24 cases of human right atrial appendage (RAA) samples were collected from patients with rheumatic heart disease during heart operation, 12 of which were clinically diagnosed as atrial fibrillation (AF); the left remained sinus rhythm (SR). Fibrosis of right atrial appendage and remodeling of connexin43 was examined by microscopy technique and ultramicroscopy technique and analyzed with an image analyzer. The collagen volume fraction of type I (CVF-I) , the size of left atrium and the volume fraction of Cx43 (Cx43VF) was studied between atrial fibrillation and sinus rhythm groups. Correlation between CVF-I and left atrial diameter was analyzed. Results (1) Microscopy examination demonstrated that CVF-I significantlyincreased( p<0.05) and Cx43VF decreased in patients with AF compared to those with SR. (2) The CVF-I was negatively correlated with the Cx43VF. (3) the size of left atrium in patients with AF is larger than that in patients with sinus rhythm. (4) No correlation between the size of left atrium and the remodeling of fibrosis was examined (r=0.33, P>0.05).Conclusion The results suggest that fibrosis and remodeling of Cx43 are involved in the pathophysiologic mechanism of human atrial fibrillation. Fibrosis of atrial muscle may play an important role in the process of atrial fibrillation by means of interfering with remodeling of connexins. Both fibrosis of atrial muscle and enlargement of left atrium may play an important role during the initiation and maintenance of atrial fibrillation by meams of different ways.