Abstract: Objective: To investigate the expression of fibrillin-1 (FBN-1) in the atrium tissue of the patients with rheumatic heart valve disease complicated with atrial fibrillation(AF), and to explore its relationship with atrial fibrosis in the patients with valvular atrial fibrillation. Methods: Eighty-four consecutive patients with rheumatic heart valve disease underwent cardiac surgery were enrolled in this study. The patients were divided into AF group(n=39) and sinus rhythm group(SR group, n=45). The clinical data of patients were collected before operation. The right atrium tissue (0.3-0.5 mm³) was disserted during operation. The degrees of right atrial fibrosis of the patients in two groups were observed by Masson staining. Western blotting method was used to measure the protein expressions of FBN-1 in atrium tissue of the patients in two groups. Results: There were no significant differences in the gender ratio, age, blood pressure, blood biochemical indicators and other aspects of medical history between two groups(P>0.05); the diameters of left and right atrium of the patients in AF group were significantly larger than those in SR group(P<0.05). The Masson staining results showed that there was obvious fibrosis in AF group, and the collagen volume fraction and collagen level in AF group were significantly higher than those in SR group (P<0.05). The expression level of FBN-1 in right atrium tissue in AF group was obviously higher than that in SR group(P<0.05). The expression level of FBN-1 protein in right atrium tissue of the patients with valvular atrial fibrillation was positively correlated with the collagen level(r=0.544,P=0.021). Conclusion: There is obvious atrium fibrosis in the patients with valvular atrial fibrillation; it is closely related to the up-regulation of the expression of FBN-1 gene.

Key words: rheumatic heart valvular disease, atrial fibrosis, atrial remodeling, atrial fibrillation, fibrillin-1