Congenital Aneurysm of the Right Appendage in a Newborn: a Rare Anomaly for Infantile Pompe Disease With Severe Cardiomyopathy?

Aneurysm of the atrial appendages is an uncommon condition, with few cases described in the literature. These aneurysms are classified into 2 groups: congenital and acquired (mainly secondary to trauma). Those affecting the left atrial appendage, which were first described by Semans and Taussing in 1938, usually manifest in the third and fourth decade of life as tachyarrhythmia refractory to pharmacological treatment and thromboembolic phenomena. Those that affect the right atrium are rarer and there are few published reports, for the most part in adults. It is essential to diagnose atrial appendage aneurysm because of the possible complications mentioned above (arrhythmia and pulmonary and systemic thromboembolism). Although sporadic reports have described aneurysm of the right atrial free wall diagnosed in newborns and even prenatally, according to our review, this is the first case of aneurysm of the right atrial appendage described in a neonate. The large size of the aneurysm and the controversial management in this type of patient are highlighted. A 2-day-old male infant was referred to the cardiology department with a prenatal diagnosis of dilatation of the right atrium (RA), with no other malformations. There were no other prenatal data of interest. The delivery was normal, at term, and there were no incidents. On physical examination, the infant was in good general condition, with good color and peripheral perfusion. On chest auscultation, the heart sounds were rhythmic and clear, and there was good bilateral ventilation. There were no other relevant clinical findings. Chest radiography disclosed considerable cardiomegaly due to RA dilatation, with no other alterations. On electrocardiography, he presented sinus rhythm at 120 bpm, without pre-excitation or other anomalies. Echocardiography in a subcostal view showed a large intrapericardial structure, anterior and to the right of the RA, and communicating with it (Fig. 1). The right appendage was very dilated, and was positioned together with the RA, as if it were a third atrium. Color Doppler showed low-velocity flow in the interior. A concomitant, 2-cm permeable foramen ovale with left to right flow was detected. The lesion was confirmed by computed tomography, which depicted a giant aneurysm of the right appendage, measuring 32 25 mm and causing slight compression of the right ventricle (RV) (Fig. 2). Taking into consideration the thrombogenic potential of the lesion, the patient’s age, and the electrocardiography findings, antiplatelet therapy and ambulatory monitoring were established, with a plan to have reparative surgery at an older age, if required. At 1 year 6 months of life, the patient remains asymptomatic, with good morphological and functional development. The lesion has been monitored with periodic ambulatory echocardiography, which has shown no significant changes in size and no internal thrombi. The foramen ovale closed spontaneously, and electrocardiography and Holter recordings remain normal. Aneurysms of the right appendage are a rare malformation of unknown origin. It is believed that the congenital type, as was seen in our case, is caused by dysplasia of the muscular wall of the