An Intriguing Right Atrial Object in a Child With Ventricular Septal Defect

Abstract

A nine-month-old-boy (weight, 5.8 kg; height, 70 cm) was taken to the operating room for surgical repair of a ventricular septal defect. Transthoracic echocardiography reported situs solitus (S,D,S) with atrioventricular and ventriculoarterial concordance, a moderate-size (8 mm) perimembranous ventricular septal defect with left-to-right shunt (pressure gradient: 60 mmHg), a dilated left atrium (left atrial indexed diameter Z-score: 2.07, left atrium/aorta ratio: 2.5 and left atrial volume index: 40 mL/m2), and left ventricle with a normal-sized coronary sinus (Fig 1). The midesophageal aortic valve short-axis view by transesophageal echocardiography revealed a circular structure in the right atrium adjacent to the superior aspect of the interatrial septum (white arrow, Fig 2, video clip 1). Following the forward rotation of the transducer angle to about 30°, the structure was slightly elongated (Fig 3). Slight retroflexion of the probe in the midesophageal four-chamber view revealed a normal-sized coronary sinus that appeared separate from the structure (Fig 4, video clip 2). The midesophageal bicaval view showed a prominent crista terminalis (white arrow) (Fig 5). Agitated saline was injected into the left upper arm vein and the contrast was found to enter the right atrium after opacifying the saccular structure (Fig 6, video clip 3). In the midesophageal bicaval view, the agitated saline entered the right atrium and there was no communication with the left atrium (Fig 7, video clip 4). Agitated saline contrast injected into the distal lumen of the central venous catheter demonstrated the contrast in the right atrium without opacification of the right atrial structure (Fig 8, video clip 5). What is this structure? Fig 2The midesophageal aortic valve short-axis view by transesophageal echocardiography revealed a circular structure in the right atrium (white arrows). View Large Image Figure Viewer Download Hi-res image Fig 3The midesophageal aortic valve short-axis view by transesophageal echocardiography with transducer plane rotated to 30° showing the saccular structure. View Large Image Figure Viewer Download Hi-res image Fig 4The midesophageal four-chamber view by transesophageal echocardiography showing the coronary sinus in the usual position. View Large Image Figure Viewer Download Hi-res image Fig 5The midesophageal bicaval view by transesophageal echocardiography displaying a prominent crista terminalis View Large Image Figure Viewer Download Hi-res image Fig 6The midesophageal aortic valve short-axis view by transesophageal echocardiography demonstrating opacification of the saccular structure following injection of agitated saline into the left upper arm vein. View Large Image Figure Viewer Download Hi-res image Fig 7The midesophageal bicaval view by transesophageal echocardiography, showing the agitated saline entering the right atrium and with no communication with the left atrium. View Large Image Figure Viewer Download Hi-res image Fig 8The midesophageal aortic valve short-axis transesophageal echocardiography view showing the agitated saline contrast injected into the distal lumen of the central venous catheter did not opacify the right atrial structure. View Large Image Figure Viewer Download Hi-res image