The causes of mildly enlarged left atrium include high blood pressure, rheumatic heart disease, etc. It is necessary to actively treat the primary disease and control the complications of enlarged left atrium. 1. Hypertension: left atrial enlargement can be seen in patients with high blood pressure, we should actively control the blood pressure level, to avoid further aggravation of atrial enlargement, commonly used antihypertensive drugs include nifedipine, valsartan and so on. 2. Rheumatic heart disease: patients often have valvular lesions, such as mitral valve stenosis or closure insufficiency, the early stage of the disease may also lead to mild enlargement of the left atrium, life should pay attention to prevent infection, to avoid further aggravation of valvular lesions, and if necessary, can be surgical treatment for valve replacement. Patients with enlarged left atrium should also pay attention to the treatment of possible complications, such as atrial fibrillation in some patients, pay attention to the prevention of recurrence of atrial fibrillation, and can follow the doctor’s instructions to take oral treatment of amiodarone, propafenone and other drugs. Patients with mildly enlarged left atrium need to consult a doctor in time, pay attention to observing the changes in the condition, and under the guidance of the physician to control the cause of the disease and treat the primary disease.