Incremental value of three-dimensional over two-dimensional transthoracic echocardiography in the assessment of cor triatriatum sinister in a child.

A 2.5-year-old boy presented with frequent hospitalizations due to recurrent respiratory tract infections with dyspnea. A fibromuscular membrane dividing the left atrium with obstruction of left atrial inflow to the left ventricle was documented by two-dimensional transthoracic echocardiography (2DTTE). Live/real time three-dimensional transthoracic echocardiography (3DTTE) provided incremental value over 2DTTE by providing en face views of the 2 obstructing orifices in the membrane enabling accurate assessment of their position, shape and size. 3DTTE also showed clearly the location of the membrane superior and proximal to the left atrial appendage which was not well delineated by 2DTTE. In addition, 3DTTE demonstrated the full extent of the left atrial appendage and careful sequential cropping of the 3D dataset showed it to have 2 distinct lobes and no thrombus. These findings provided comprehensive assessment of the lesion and were helpful in surgical decision making and planning.