Large atrial septal defect visualized by real-time three-dimensional echocardiography

Abstract

A 29-year-old man was hospitalized because of dyspnea and palpitation. Electrocardiography demonstrated normal sinus rhythm and borderline right atrial enlargement. Twodimensional transthoracic echocardiography (2D-TTE) revealed a normal left ventricular systolic function. There was a paradoxical septal motion consistent with right ventricular volume overload (Fig. 1a). Although the right ventricle was mildly dilated, its systolic function was preserved. 2D-TTE revealed a large atrium without distinct interatrial septum (Fig. 1b). Left-to-right shunt flow was not detected clearly through the defect on color-flow Doppler imaging. Real-time three-dimensional echocardiography (RT3D-TTE) visualized a large defect of interatrial septum clearly (Fig. 2). The patient was referred for surgery. Only a tiny vestige of the interatrial septum could be confirmed with the naked eye, and the two atrioventricular valves were normal. The patch closure was performed successfully using a fresh autologous pericardial patch. Atrial septal defect (ASD) is a common congenital heart disease presenting in adulthood. Our patient showed a large secundum ASD like single atrium. It is sometimes difficult to distinguish a large secundum ASD from a single atrium. Levy et al. recommended that the term ‘‘single atrium’’ should be used to denote a condition comprising: (1) complete absence of the interatrial septum, (2) absence of malformation of the atrioventricular valves, and (3) absence of interventricular communication [1]. In our case, the morphological diagnosis was supposed to be a large secundum type atrial septal defect, because a small part of the interatrial septum was found. In this case, RT3D-TTE enhanced the understanding of the anatomy and spatial relationship between the defect and its adjacent structure. Previous study has shown the usefulness of RT3D-TTE for patient selection for surgical or transcatheter closure of atrial septal defects. It has been reported that RT3D-TTE allows accurate determination of the ASD location, ASD size, and surrounding tissue of the interatrial septum [2, 3]. Although our patient demonstrated a large part to be missing from the interatrial septum, RT3D-TTE could clearly visualize a large defect of the interatrial septum. RT3D-TTE provided additional, clinically relevant qualitative information for the evaluation of this patient with a large defect of the interatrial septum. N. Watanabe Y. Tanabe Division of Medical Support, Okayama University Hospital, Okayama, Japan