En Face View of Atrial Septal Defect by Two-Dimensional Transthoracic Echocardiography: Comparison to Real-Time Three-Dimensional Transesophageal Echocardiography

Background: It is generally believed that three-dimensional (3D) echocardiography can provide unique en face views of atrial septal defects (ASDs), whereas conventional two-dimensional (2D) transthoracic echocardiography (TTE) cannot. The purpose of this study was to develop a special 2D TTE-based en face view of ASDs. Methods: En face views of ASDs on 2D TTE were obtained in 415 consecutive adult patients and compared with the results of real-time 3D transesophageal echocardiography in 25 of these patients. Results: Acceptable en face views of ASDs on 2D TTE were obtained in 80% of patients, in whom secundum ASDs could be adequately imaged in more standard 2D imaging planes. The ability to visualize en face views of ASDs on 2D TTE was inversely related to their sizes (P < .05). The differences in the major and minor dimensions of ASDs between 2D TTE and real-time 3D transesophageal echocardiography were not statistically significant (P > .05). Conventional 2D transthoracic echocardiographic views significantly underestimated ASD size with superior-inferior directional major axis. Conclusion: Two-dimensional TTE can provide en face views of ASDs and their spatial orientations with respect to neighboring structures. This method may provide incremental information to 3D echocardiography in patients with ASDs. (J Am Soc Echocardiogr 2010;23:714-21.)