Abstract: Objective To investigate the influence of iron deficiency on left atrial remodeling in patients with non-valvular atrial fibrillation. Methods From December 2017 to April 2019,240 inpatients with non-valvular atrial fibrillation admitted to the department of cardiology of Beijing Moslem People's Hospital were enrolled in our study.Iron metabolism indexes (including serum iron,total iron binding capacity,ferritin and transferrin) were tested and transferrin saturation was calculated.According to the level of ferritin and transferrin saturation,135 patients were assigned into iron deficiency group and 105 cases into non-iron-deficiency group.Whether patients suffered from anemia was evaluated,and the left cardiac structure was measured by echocardiography,and the impact of iron deficiency on left atrial remodeling in patients with non-valvular atrial fibrillation was investigated. Results The level of NYHA heart function,left atrium diameter (LAD,4.31±0.80 cm vs 3.84±0.61 cm),and left ventricular end diastolic dimension (EDD,4.74±0.72 cm vs 4.29±0.76 cm) were significantly higher in iron deficiency group compared to non-iron-deficiency group (all P<0.05);however,there was no significant difference in the level of hemoglobin and the prevalence rate of anemia between the two groups (P>0.05).In subgroup analysis,whether suffered from anemia or not,LAD (4.50±1.01 cm,4.15±0.51 cm vs 3.99±0.49 cm,3.75±0.65 cm) and EDD (4.55±0.78 cm,4.89±0.62 cm vs 4.38±1.01 cm,4.23±0.53 cm) were significantly higher in atrial fibrillation patients with iron deficiency compared to atrial fibrillation patients without iron deficiency (all P<0.05).Correlation analysis showed that LAD was negatively correlated with serum iron (r=-0.311,P=0.001),transferrin saturation (r=-0.362,P=0.000),and ferritin (r=-0.468,P=0.000).Multivariate linear regression analysis showed that LAD was significantly correlated with iron deficiency (B=-0.358,P=0.000). Conclusion Iron deficiency may be a contributing factor to left atrial remodeling,and continuous progression of iron deficiency has an adverse effect on the maintenance of atrial fibrillation.