Abstract: AIM To study the relationship between atrial fibrillation (AF) and cardiac structure in patients with chronic obstructive pulmonary disease (COPD). METHODSA total of 426 COPD patients were divided into two groups: sinus rhythm group (n=376) and primary atrial fibrillation group (n=50). Logistic regression analysis was conducted to evaluate the relation between AF and factors such as age, gender, COPD duration, underlying diseases, drug use and echocardiography results. RESULTSUnivariate analysis indicated a significant difference in age, history of coronary heart disease, right ventricular diameter, left atrium diameter, right atrial diameter and pulmonary artery diameter (P<0.05). Stepwise logistic regression analysis showed that left atrium diameter (P<0.05) and right atrial diameter (P<0.05) were risk factors for primary atrial fibrillation. CONCLUSIONIn COPD patients with AF, pulmonary artery pressure obviously increases and left and right atrium diameters obviously enlarge. Left and right atrium diameters are predictors for AF occurrence.