Discussion

Although left atrial appendage aneurysm has life-threatening complications, its diagnosis is mostly incidental. It is extremely rare diagnosed in childhood. ^{Reference Chowdhury, Seth, Govindappa, Jagia and Malhotra1–Reference Zhang, Li and Cao3} In this article, we have reported two cases diagnosed in the neonatal period.

Left atrial appendage aneurysm can be congenital or acquired. The cause of congenital left atrial appendage aneurysm is dysplasia and attenuation of the pectinate muscles. Acquired left atrial appendage aneurysm develops secondary to left atrial pressure increase due to mitral valve disease or left atrial wall weakening related to tuberculosis or syphilitic myocarditis. ^{Reference Tandon, Arisha and Nanda4} Symptoms associated with left atrial appendage aneurysm usually appear during the second to fourth decades of life. The most common symptoms are palpitations and/or dyspnoea. Arrhythmia especially atrial arrhythmias, intracardiac thrombus, thromboembolic events, atrial fibrillation, and heart failure are serious complications of left atrial appendage aneurysm. ^{Reference Aryal, Hakim and Ghimire5}

Transthoracic echocardiography plays an important role in the diagnosis of left atrial appendage aneurysm. An aneurysm sac communicating with the left atrium cavity can be detected by transthoracic echocardiography, and the presence of a thrombus in the aneurysm can be seen. In addition, blood exchange between the aneurysm and left atrium can be demonstrated by colour Doppler echocardiography. ^{Reference Tidake, Gangurde and Mahajan6} MRI or CT can be used for differential diagnosis and evaluation of compression on adjacent structures. Congenital deficit of pericardium, solid or cystic paracardiac tumours, appendage juxtaposition, mediastinal mass, dilated coronary sinüs, and left ventricle pseudoaneurysm are the differential diagnoses of left atrial appendage. ^{Reference Aryal, Hakim and Ghimire5} We diagnosed left atrial appendage aneurysm with transthoracic echocardiography in both of our two patients and confirmed the diagnosis with CT. There is no consensus on which size should be named as aneurysm, especially in children. Aryal et al suggested that, if the left atrial appendage has increased 1.5-fold compared to its normal size, it can be called an left atrial appendage aneurysm ^{Reference Aryal, Hakim and Ghimire5} .

The recommended treatment for left atrial appendage aneurysm is surgical resection, but there is no consensus on the timing of surgery. In our first patient, we preferred surgical resection by performing cardiopulmonary bypass because of compression findings on CT and clinical worsening. But we lost our patient because of the comorbidities. Since our second patient was asymptomatic and there were no signs of compression on CT, we decided to follow up closely. Some prefer conservative treatment, especially in small aneurysms without intracardiac thrombus. Plonska-Gosciniak et al reported a patient with left atrial appendage aneurysm accompanied by supraventricular arrhythmia with drug therapy at the 20-year follow-up. ^{Reference Płońska-Gościniak, Larysz and Jurczyk7} Similarly, Valentino et al reported a case who was followed up with drug management for 5 years and then underwent surgery. ^{Reference Valentino, Al Danaf and Morris8} In addition, some authors recommend early surgery even if they are asymptomatic ^{Reference Tanoue, Kado, Shiookawa and Sagawa9} .

There are few cases in the literature that newborns were diagnosed with left atrial appendage aneurysm in the first 1 month of life and undergone surgery. Therefore, we reported these two cases. The surgery time for left atrial appendage aneurysm varies according to the patient’s symptoms and clinical experience, and there is no consensus on treatment and follow-up. We recommend CT or MRI for differential diagnosis and/or compression findings to patients diagnosed as left atrial appendage aneurysm with transthoracic echocardiography.