Enlarged left atrium X-ray mainly shows the heart enlarged to the left side, which is often not easily detected. In severe cases, it will compress the right ventricle and its surrounding tissues, the most typical manifestation is the esophageal pressure trace, which disappears in severe left atrial enlargement. The landmark reference in the orthopantomogram of the chest is the thoracic spine. If the left atrium is enlarged beyond the thoracic spine, the presentation is severe; if it does not exceed the thoracic spine, the presentation is mild or moderate. The left lateral radiograph reveals the loss of the zona pellucida between the left atrial bulge and the left bronchus; the posterior lateral radiograph reveals a marked increase in the left atrial auricle and its length; and the right lateral radiograph fails to reveal significant abnormalities of left atrial enlargement. Chest X-ray can only identify the left atrial enlargement briefly, and it has some guiding significance in determining the severity of the left atrium, and the chest CT examination can be perfected to clarify the degree of left atrial enlargement if necessary.