Echocardiographic diagnosis of atrial septal aneurysm in an infant with hypoplastic right heart syndrome.

Echocardiographic findings are described in a patient with hypoplastic right heart syndrome (pulmonary atresia type with intact ventricular septum and small right ventricular cavity) who had an associated atrial septal aneurysm. An unusual appearance of echoes behind the aorta bulging into the left atrium in diastole on both the M-mode and cross-sectional echo suggested this diagnosis prior to cardiac catheterization. The angiographic findings confirmed the diagnosis of right ventricular hypoplasia, pulmonary atresia and the large atrial septal aneurysm. The infant died after surgery and the atrial septal aneurysm was observed at autopsy. The importance of the diagnosis of the atrial septal aneurysm and its association with restriction of right-to-left atrial shunting prompts this report.