Assessment of Sinus Venosus-Type Atrial Septal Defect

by Denisa Muraru, MD, PhD; Patrizia Aruta, MD
Department of cardiac, thoracic and vascular sciences, University of Padua, School of Medicine, PaduA, Italy

Clinical Case

  • Male, 21 year-old
  • Incidentally diagnosed with right heart enlargement by echocardiography at pre-participation screening before engaging in competitive sport activity
  • Asymptomatic
  • Referred for further diagnostic workup

2D-guided M-mode in parasternal short-axis view, showing a dilated right ventricle (RV) and an abnormal septal motion pattern suggestive of RV volume overload

Although it was difficult to obtain conventional views due to thoracic deformity (pectus excavatum), 4-chamber view confirmed an enlarged right ventricle, visible at the apex, with abnormal septal motion

Three-dimensional echocardiographic analysis of the RV (4D RV Function 2.0®, TomTec Imaging System, Germany), showed a dilated RV (EDV= 96 ml/m2) with preserved ejection fraction

Parasternal short-axis view revealed a small left-to-right interatrial shunt due to a patent forame ovale (PFO). Three-dimensional reconstruction confirmed the presence of a very small foramen ovale, which could not explain the RV overload.

From 4-chamber view, except for the PFO with very small left-to-right shunt, there was no clear evidence of other atrial septal defect (ASD) or anomalous return of pulmonary veins.

From an unconventional parasternal long-axis view focusing on far right structures, a large left-to-right shunt through a sinus venosus-type ASD was clearly evident, with anomalous return of one pulmonary vein

A 3D data set was obtained from the same parasternal approach and cropped to display the ASD en face (visualized from the right atrial perspective)

The ASD shape was elliptical, and its maximal size could be quantified in terms of maximal and minimal linear dimension and area.

3D color flow confirmed that the defect seen in 3D was real and not a dropout artifact.

3D color flow confirming the large interatrial shunt and the partial anomalous return of pulmonary vein

Key Messages

2D echocardiography:

  • Enabled the visual identification of RV volume overload, and the diagnosis of 2 types of interatrial shunt
  • The diagnosis of sinus venosus ASD was difficult by transthoracic echocardiography, requiring experience in obtaining unconventional views and in interpreting echo findings (PFO with hemodynamically non-significant shunt and unexplained RV volume overload)

3D echocardiography:

  • By its ability to demonstrate the defects en face, with their dynamic size and shape displayed throughout the cardiac cycle, 3D echo increased the confidence in the diagnosis
  • Allowed to quantify separately the size of both orifices (ASD and PFO), including the ASD area, and not just one linear dimension – without any possibility to control if it is really the largest – that is usually performed by 2D echo
  • Color 3D confirmed the presence of shunt and of anomalous venous return suspected by 2D


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