Enlargement of the left atrium may be caused by mitral stenosis, hypertension, aortic stenosis, atrial fibrillation, etc. It usually cannot be cured by itself, and it is recommended that the patient be actively treated to prevent the condition from progressing and affecting the therapeutic effect. 1. Mitral stenosis: Mitral stenosis causes blood flow from the left atrium to the left ventricle, and the accumulation of blood in the left atrium will cause the left atrium to enlarge. 2. Hypertension: Aortic pressure increases in patients with high blood pressure, and the pressure is then transmitted to the left ventricle and left atrium, and the patient will experience left atrial hypertrophy and enlargement, which cannot be cured on its own, and can be treated with antihypertensive medications such as captopril and nifedipine. 3. Aortic valve stenosis: Aortic valve stenosis leads to obstruction of blood flow from the left atrium and left ventricle to the aorta, and the left atrium enlarges in order to beat and pump blood harder, which is usually not cured by itself and can be treated by artificial valve replacement. 4. Atrial Fibrillation: Atrial fibrillation disrupts the contraction pattern of the atria, the ejection function of the left atrium is weakened, and the accumulation of blood in the left atrium will cause the left atrium to enlarge. It is recommended that patients actively cooperate with the doctor’s treatment and choose the appropriate treatment plan under the doctor’s guidance.