Objective: To investigate the relationship between platelet-derived growth factor-A (PDGF-A) and atrial fibrosis in patients who have developed atrial fibrillation (AF) secondary to rheumatic valvular disease. Methods: 84 selected patients participated in the current study who have developed rheumatic heart disease and were going to have a cardiac surgical operation. In the current study, whole subjects were divided into two group, they were atrial fibrillation (AF) group (the quantity is thirty-nine) and sinus rhythm (SR) group (the quantity is forty-five). Before the operation, complete clinical data was available for the whole patients. During the operation, the right atrial tissue (0.3 -0.5 mm 3 ) was disserted from every patient. Right atrial fibrosis was observed by Masson staining and the distribution of PDGF-A in right atrium specimen was observed by immunohistochemistry. RT-PCR techniques were applied to admeasure the mRNA expressions of PDGF-A in patients' atrial tissue. At the same time, western-Blot techniques were employed to admeasure the protein expressions of PDGF-A. Results: In baseline clinical characteristics, in both AF group and SR group, there was no apparently difference between them (P > 0.05); compared with SR group, the diameters of left atrium and right atrium in AF group were apparently increased (P < 0.05). The results of Masson staining revealed that the atrial tissue fibrosis was clearer in AF group, and collagen volume fraction in the AF group was evidently exceeding SR group (P < 0.05). The expressions of PDGF-A's mRNA and protein from right atrial tissue in the AF group were evidently greater than SR group (P < 0.05). The mRNA and protein expressions of PDGF-A and the right atrium diameter go hand in hand. Conclusion: Atrial

Objective: To investigate the expression of Platelet-derived growth factor receptor alpha (PDGFR-α) in patients who have valvular atrial fibrillation. Methods: In this research, eighty-four patients with rheumatic heart disease who were going to undertake cardiac surgery were included. The subjects were divided into two groups: the AF group and the sinus rhythm group, the quantities are 39 and 45 respectively. Before the surgery, baseline demographics, physical examination, routine laboratory testing, echocardiography, echocardiographic data and additional clinical data were available for all patients. The right atrial tissue of the subjects was separated during surgery, with an area of approximately 0.3 -0.5 mm 3 . Immunofluorescence staining was used to analyze the distribution of PDGFR-α of atrial tissue. mRNA of PDGFR-α in atrial tissue were determined by real-time quantitative PCR (Polymerase Chain Reaction); Western-Blot technique was used to measure the protein of PDGFR-α in atrial tissue. Results: There were no significant differences (P > 0.05) in sex ratio, age, blood pressure, blood biochemistry, and other aspects of medical history between the two groups. However, the right and left atrium diameters in the AF group were markedly larger than those in the SR group (P < 0.05). Moreover, the mRNA and protein of PDGFR-α from right atrial tissue were obviously higher in the AF group than that in the SR group (P < 0.05). Conclusion: The expression of PDGFR-α in the right atrial tissue of patients with atrial fibrillation was found to be significantly higher.