Impact Of Atrial Fibrillation On Connexin In Atrial Pulmonary Antrum And Left Atrium

Objective: Connexin (Cx) plays an important role in perpetuation of atrial fibrillation (AF). Pulmonary vein antrum has been regarded as a vital target for AF ablation. However, little is known about the mechanism of atrial pulmonary vein antrum as an interrupted target. This study aimed to investigate the impact of AF on connexin in pulmonary vein antrum and left atrium.Methods:Twenty patients underwent surgery operation were divided into AF group and sinus rhythm group. Samples were obtained from atrial pulmonary vein antrum and left atrium during operation. Western blot was applied for measurement of connexin. Cx40 and Cx43 were analyzed at two sites in two groups.Results:⑴In sinus rhythm group, Cx remained unchanged at two sites (Cx40:4994.12±1290.46 Int×mm~2 vs 4333.12±1270.89 Int×mm~2, P=0.289; Cx43:5014.46±961.46 Int×mm~2 vs 4916.43±697.27Int×mm~2, P=0.808);⑵In AF group, Cx40 remained unchanged at two sites (5084.3±1497.35 Int×mm~2 vs 5149.78±820.36Int×mm~2,P=0.9);Cx43 decreased significantly in pulmonary vein antrum than that in left atrium(4528.21±982.79 Int×mm~2 vs 8216.65±1670.65 Int×mm~2, P<0.001);⑶AF had little impact on Cx40 and Cx43 in pulmonary vein antrum(Cx40:4994.12±1290.46 Int×mm~2 vs 5084.3±1497.35 Int×mm~2, P=0.888;Cx43:5014.46±961.46 Int×mm~2 vs 4528.21±982.79 Int×mm~2, P=0.281).⑷AF resulted in the increases of Cx at left atrium ( Cx40: 4333.12±1270.89 Int×mm~2 vs 5149.78±820.36 Int×mm~2, P=0.099; Cx43: 4916.43±697.27 Int×mm~2 vs 8216.65±1670.65 Int×mm~2, P<0.001).Conclusion: Distribution of connexin remaines consistent at pulmonary vein antrum and left atrium in patients with sinus rhythm. Atrial fibrillation has little impact on connexin in atrial pulmonary vein antrum. However, results in the increases of Cx at left atrium. It indicates that changes of connexin distribution resulted from atrial fibrillation may contribute to the maintenance of atrial fibrillation. Ablation around pulmonary vein antrum may block or modify the connexin remodeling, thereby inhibites the atrial fibrillation.