Circulating type IV collagen 7S concentrations are associated with left atrial remodeling indices in patients with atrial fibrillation

OBJECTIVE: Non-alcoholic fatty liver disease is a risk factor for atrial fibrillation. We assessed whether liver fibrosis markers are associated with atrial remodeling indicators in patients with atrial fibrillation in whom fatty liver disease has not been identified. METHODS: In this prospective, observational study, 174 patients with atrial fibrillation without chronic liver disease who underwent catheter ablation were enrolled. Using blood collected from the right atrium, type IV collagen (COL4), type IV collagen 7S (COL4-7S), and tumor necrosis factor-α concentrations were measured as markers of liver fibrosis and inflammation. The left atrial volume and P-wave duration were used as atrial remodeling indicators. RESULTS: Left atrial volume was significantly positively correlated with COL4, COL4-7S, and tumor necrosis factor-α concentrations. COL4-7S concentrations were significantly positively correlated with tumor necrosis factor-α concentrations and the P-wave duration. To exclude the effect of alcohol consumption, a multiple regression analysis was performed for left atrial volume in patients with a <30-g daily alcohol intake (n = 124). Age, sex, and COL4-7S were significant explanatory variables (R = 0.44, adjusted R2 = 0.142, COL4-7S standardized β = 0.20). CONCLUSION: Liver fibrosis may be involved in atrial remodeling via inflammation in patients with atrial fibrillation who do not have obvious fatty liver disease.