Neonatal Management of a Giant Right Atrial Appendage Aneurysm
Aneurysms of the right atrial appendage are extremely rare, particularly in pediatric patients. A recent review identified just 17 cases reported in the literature to date, with only 3 cases identified in neonates.1 These aneurysms can be associated with tachyarrhythmia, intracardiac thrombus formation, thromboembolism, and right ventricular compression precipitating heart failure.1,2 In some instances, enlargement of the appendage may be related to idiopathic dilation of the entire right atrium, an entity that has been associated with sudden death.3 We present the case of a neonate diagnosed in utero with a right atrial appendage aneurysm that dramatically enlarged during the first weeks of life.
The right atrial appendage aneurysm was first detected on fetal echocardiogram at 28 weeks of gestation (Figure 1). There were no pregnancy complications, including no fetal arrhythmias or evidence of fetal hydrops. The baby was born at 36 weeks gestation via vaginal delivery with good initial hemodynamics and an unremarkable physical examination. Postnatal echocardiography on the first day of life demonstrated an enlarged right atrial appendage aneurysm (1.2×0.9 cm), a small secundum atrial septal defect, and otherwise normal intracardiac anatomy. A Holter monitor study showed no evidence of ectopy or arrhythmia. The patient was started on aspirin therapy for anticoagulation and discharged home on the third day of life.
At outpatient follow-up at 4 weeks of age, the baby was clinically well and without symptoms. Transthoracic echocardiography demonstrated a marked interval increase in the size of the aneurysm (4.0×2.4 cm), now associated with dynamic compression of the right ventricle. To confirm the diagnosis and to distinguish from pericardial effusion, an agitated saline study was performed that demonstrated opacification of the right atrial appendage aneurysm and right ventricle. Contrast was also seen in the left side of the heart, consistent with an atrial communication (Movies I and II in the online-only Data Supplement and Figure 2).
Given the progressive increase in the size of the aneurysm with evidence of right ventricular impingement, the patient was referred for resection of the aneurysm at 5 weeks of age. The aneurysm was approached via a partial sternotomy. At surgery, the right atrial appendage aneurysm filled the entire anterior pericardial space (Figure 3). Transesophageal echocardiography showed the giant aneurysm occupying a position anterior to the right ventricle and extending to the apex of the heart (Figure 4 and Movie III in the online-only Data Supplement). Dynamic compression of the right ventricular free wall was present, and shunting across the atrial septum was bidirectional (Movie IV in the online-only Data Supplement). The ostium between the right atrial cavity and the appendage measured 1.8 cm. No thrombus was seen within the aneurysm. Resection of the aneurysm was performed without cardiopulmonary bypass. Because the atrial septal defect was small and the patient had no evidence of pulmonary overcirculation, the decision was made to not subject the patient to cardiopulmonary bypass to repair this defect. Postoperative imaging demonstrated normal biventricular function, no wall motion abnormalities, and left-to-right atrial level shunting (Movie V in the online-only Data Supplement). Pathological evaluation of the aneurysmal tissue demonstrated thinning of the atrial wall with subendocardial, pericardial, and patchy interstitial fibrosis associated with attenuation and partial fibrous replacement of cardiac myocytes (Figure 5). The patient was discharged on the third postoperative day after an uncomplicated hospitalization. At the latest follow-up at 4 months of age, the child was asymptomatic and thriving.
Right atrial appendage aneurysm is a very rare anomaly in pediatric patients. With advancements in imaging techniques, prenatal diagnosis via fetal echocardiography is possible. Surgical resection of right atrial appendage aneurysm is recommended for patients with symptoms or progressive enlargement. Resection can be performed safely without cardiopulmonary bypass via a limited sternotomy. After resection, the long-term prognosis should be favorable because recurrence has not been reported.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.115.017123/-/DC1.
- © 2015 American Heart Association, Inc.