There are many reasons for mild left atrial enlargement, which can be categorized into physiologic and pathologic left atrial enlargement, physiologic without treatment, and pathologic requiring drug treatment. Mild enlargement of the left atrium can be found in most normal people, and most of them are primary enlargement of the heart structure, which can be observed clinically. Another category is caused by pathological factors, such as chronic pulmonary heart disease, dilated cardiomyopathy, coronary heart disease and other diseases, there will be a mild enlargement of the left atrium, and there will be corresponding clinical symptoms, which need to be treated with drugs. When the left atrium is enlarged, it can affect the contractile function of the left atrium as well as its electrical activity, and various types of arrhythmias may occur, such as atrial tachycardia, atrial flutter, atrial fibrillation, etc. In severe cases, it can lead to heart failure. In severe cases, it can lead to heart failure, which seriously affects the function of the heart. A few can also compress the lung tissue, thus affecting the lung function. Therefore, this condition requires a comprehensive evaluation in a regular hospital, regular follow-up, and rational choice of medication.