In general, enlargement of the right atrium is due to mitral valve pathology or heart failure of various causes. In addition, right atrial enlargement can also occur in cases of ventricular septal defect, patent ductus arteriosus, congenital heart disease, heart valve disease, and obstructive hypertrophic cardiomyopathy. Atrial enlargement is a secondary pathological change, usually secondary to myocardial disease, or endocrine metabolic diseases, hypertension, etc., can cause right atrial enlargement. For example, if a patient has pulmonary hypertension due to long-term hypertension, the right atrium will also be enlarged. In addition, in patients with hyperthyroidism and hyperparathyroidism, right atrial enlargement can also occur. Therefore, when treating right atrial enlargement, it is important to treat it actively according to the primary cause.