Cross-sectional echocardiography has made a major contribution to the preoperative evaluation of the patient with an atrioventricular septal defect,1−5 such that in many instances this modality has been the sole imaging technique used to formulate a medical or surgical plan6. With the advent of Doppler echocardiography additional hemodynamic information is now available, which enables the cardiologist and surgeon to evaluate the site and magnitude of associated atrioventricular valvar regurgitation, and obtain an accurate measurement of pulmonary arterial pressure along with an assessment of outflow tract obstruction, if present.