The harm of enlarged left atrium may lead to pulmonary stasis, left heart failure, etc. The treatment includes controlling blood pressure, taking medicines such as captopril and valsartan as prescribed by the doctor, and regular rechecking of cardiac ultrasound. 1. Harm: pulmonary artery return is affected. The left atrium increases in size, the left atrium increases in blood filling and the pressure gradually increases, which affects the pulmonary artery reflux, and if the reflux is blocked for a long time, it may lead to the occurrence of pulmonary stasis, and in serious cases, it may lead to left heart failure or even systemic failure, which is life-threatening. 2. Treatment: generally long-term high blood pressure will cause the enlargement of the left atrium, at this time the first task is to control blood pressure, can follow the doctor’s instructions to choose antihypertensive drugs, such as valsartan or captopril, etc., can improve the patient’s blood pressure. Secondly, if the patient’s heart rate can be tolerated and there is no serious lung disease, the patient can follow the doctor’s instructions to take beta-blocker drugs, which can also prevent changes in heart morphology, the common ones are bisoprolol, metoprolol and so on. At the same time, it is necessary to review the heart ultrasound regularly, and the usual diet should be low-salt and low-fat to prevent further development of the disease. If left atrial enlargement is suspected, it is important to seek timely medical treatment.