Left atrial appendage aneurysm is an extremely rare cardiac anomaly with serious complications. It is rarely diagnosed in childhood. Herein, we reported two newborns diagnosed with left atrial appendage aneurysm.

We describe a newborn with a congenital left atrial appendage aneurysm. The aneurysm size did not change prenatally. However, it rapidly enlarged after birth. MRI was useful for assessing the aneurysm extent and exact size, and for diagnosis. Respiratory distress and feeding difficulties appeared, and surgery was performed. These symptoms disappeared post-operatively. The patient is alive without complications or recurrence.

The left atrial appendage congenital aneurysm is an extremely rare heart defect. The entity can remain asymptomatic for a long time; however, it may lead to life-threatening morbidity or death.

Limited literatures report the management of congenital left atrial appendage aneurysm (LAAA) which is extremely rare. Chest X-ray firstly showed an enlarged left cardiac silhouette for a 3-year-old patient with pneumonia. Echocardiography and magnetic resonance imaging confirmed a large cyst attached to the left atrium. Aneurysmectomy was performed through lateral thoracotomy using step-by-step method and under the guidance of transoesophageal echocardiography. We aim to show the safety and efficacy of this approach applied to children associated with congenital LAAA.

We present a rare case of an asymptomatic giant congenital left atrial appendage aneurysm in a 19-year-old girl. We believe this is the largest congenital left atrial appendage aneurysm reported without any symptom.