To assess the value of echocardiography in the diagnosis and treatment of left atrial appendage aneurysm (LAAA) in children.

Nine children with LAAA diagnosed by echocardiography from March 2016 to March 2021 at Beijing Children's Hospital, Capital Medical University were retrospectively selected. We summarized and analyzed their clinical data, echocardiographic findings, treatment follow-up, and prognosis results.

Of the nine patients with LAAA, four were male and five were female. They ranged in age from 34 days to 12 years and 11 months, and the reasons for presentation were cardiomegaly, atrial tachycardia, heart murmur, and mediastinal mass. Two-dimensional ultrasound showed a cystic anechoic structure in the lateral of the left ventricle, communicating with the left atrium, with a long diameter of (32.3±12.9) mm and a short diameter of (16.4±6.9) mm for LAAA, a round trip between LAAA and left atrial blood flow signals was observed by color Doppler, and giant LAAA could compress the left ventricle. One of the nine patients had compression of the lateral wall of the left ventricle, two had congenital heart disease, two had space-occupying lesions (one mediastinal mass and one pulmonary tumor), and one had mitral stenosis with insufficiency. There was no thrombosis, pericardial defect, or coronary artery and pulmonary vein compression. All were intrapericardial LAAAs. In one patient, the left ventricle was compressed due to the tumor, and the LAAA was surgically removed, and the shape, size, and function of the left heart were normal after surgery. One patient was treated with antiarrhythmic drugs and one patient underwent mediastinal tumor resection, and the LAAA was smaller than before in both cases.

LAAA is a rare cardiac malformation. Echocardiography can accurately diagnose LAAA in childhood, determine whether there is thrombosis and whether it compresses adjacent structures, and help to find the causes and evaluate the therapeutic effect.