If Down syndrome or another chromosomal abnormality is suspected, chromosome studies are indicated. Chest radiography frequently shows cardiomegaly, mostly right atrial and right ventricular enlargement from volume and pressure overload. It can be the first sign of congenital heart disease in the adult. In addition, an increase in pulmonary vascular markings from increased pulmonary flow may be appreciated, along with a prominent pulmonary artery. Evidence of hyperaeration, flattened diaphragms, and air trapping also may be present, particularly in children with Down syndrome.
Echocardiography reveals defects of the atrial and ventricular septae.
Echocardiography also can identify a single left ventricular papillary muscle that, if unrecognized by the surgeon, may influence the success of mitral reconstruction. In some centers, 3-D reconstruction of echocardiographic images is being used to evaluate AV valve morphology. Abnormal AV valve leaflets may be classified into 3 types. Rastelli type A involves minimal bridging of the superior cushion-derived leaflet and attachment of the leftward component of the anterior bridging leaflet to the crest of the interventricular septum. Doppler echocardiography can demonstrate common AV valve regurgitation as well as flow through the atrial and ventricular septal defects.