Transesophageal echocardiographic evaluation of atrial septal defects--how to explore the third dimension?

One of the recurring themes in the field of echocardiography is the fallacies inherent in exploring cardiac structures in two dimensions because they essentially exist in three dimensions. Attempts to overcome this limitation of echocardiography led to the evolution of echocardiography from the era of unidirectional M-Mode echocardiography to present day advent of three dimensional echocardiography. Recent development of the transesophageal probes with capability of three dimensional imaging are the latest addition to echocardiographic imaging modalities. One of the important uses of three dimensional transesophageal echocardiography is evaluation of atrial septal defects, where two dimensional echocardiography is known to have led to serious errors in assessment of the defect and three dimensional imaging from the transthoracic approach may not be possible in adults due to poor echo window. Present article suggests a uniform approach to evaluate the atrial septal defects in three dimensions by integrating relevant anatomical concepts with technique of three dimensional transesophageal echocardiography.