Objective-To determine whether transthoracic three dimensional echocardiography is an accurate non-invasive technique for defining the morphology of atrial septal defects (ASD). Methods-In 34 patients with secundum ASD, mean (SD) age 20 (17) years (14 male, 20 female), the measurements obtained from three dimensional echocardiography were compared to those obtained from magnetic resonance imaging (MRI) or surgery. Three dimensional images were constructed to simulate the ASD view as seen by a surgeon. Measured variables were: maximum and minimum vertical and horizontal ASD dimension, and distances to inferior and superior vena cava, coronary sinus, and tricuspid valve. In each patient two ultrasound techniques were used to acquire three dimensional data: standard grey scale imaging (GSI) and Doppler myocardial imaging (DMI). Results-Good correlation was found in maximum ASD dimension (both horizontal and vertical) between three dimensional echocardiography and both MRI (GSI r = 0.96, SEE = 0.05 cm; DMI r = 0.97, SEE = 0.04 cm) and surgery (GSI r = 0.92, SEE = 0.06 cm; DMI r = 0.95, SEE = 0.06 cm). The systematic error was similar for both three dimensional techniques when compared to both MRI (GSI = 0.40 cm (27%); DMI = 0.38 cm (25%)) and surgery (GSI = 0.50 cm (29%); DMI = 0.37 cm (22%)). A significant diVerence was found in both horizontal and vertical ASD dimension changes during the cardiac cycle. This change was inversely correlated with age. These findings were consistent for both DMI and GSI technique. In children (age < 17 years), the feasibility of detecting structures and undertaking measurements was similar for both echo techniques. However, in adult ASD patients (age > 18 years) this feasibility was higher for DMI than for GSI. Conclusions-Transthoracic three dimensional imaging using both GSI and DMI accurately displayed the varying morphology, dimensions, and spatial relations of ASD. However, DMI was a more eVective technique than GSI in describing ASD morphology in adults.

Critical obstruction of the aorta presenting in the neonate typically occurs with aortic interruption or coarctation, following ductus arteriosus closure. Circumflex retroesophageal aortic arch is a rare aortic arch anomaly in which a right aortic arch continues as a retroesophageal component and descends on the left of the spine. Obstruction within the arch can occur, usually identified incidentally in older children. We report a neonate with circumflex aorta with ventricular septal defect in which there was hypoplasia of the retroesophageal segment. The patient presented with cardiovascular collapse following duct closure mimicking aortic interruption. The case is presented, together with the surgical repair.