日本小児循環器学会雑誌 Pediatric Cardiology and Cardiac Surgery

Semans and Taussig first described congenital left atrial appendage aneurysm (LAAA) in 1938. However, it is very rare and has seldom been reported. The congenital reasons for its development are unknown. Although it is asymptomatic during the infantile period, it is usually resected in order to prevent symptoms that are commonly associated with it, including supraventricular arrhythmia, compression of the coronary arteries, dyspnea, intracardiac thrombus, and pulmonary venous stenosis. Here we report on the surgical management of an asymptomatic 2-year-old girl with this anomaly. Transthoracic and transesophageal echocardiography did not reveal thrombosis in the left appendage, and contrast-enhanced computed tomography of the LAAA demonstrated no abnormal structures. After median sternotomy, aneurysmectomy was performed under cardiopulmonary bypass without cross-clamping. The patient underwent successful surgical resection of the aneurysm.

Pathological examination revealed the three levels of atrial structure epicardial, myocardial, and endocardial layers; thinning of the muscular layer; and mucous degeneration, classifying the LAAA into an intrapericardial aneurysm of the left atrial appendage. Tissue destruction and the inability to maintain tissue homeostasis may have contributed to the formation of the LAAA.