Four-chamber view on 2D echocardiography during diastole showing a complete atrioventricular (AV) septal defect Rastelli type A. There is a common AV valve, which makes it difficult to use the valves to identify the ventricles. Note that the moderator band is seen on the ventricle of the right (morphologic RV). The morphologic right atrium (mRA) drains into the left ventricle, while the morphologic left atrium (mLA) drains into the right ventricle, suggestive of atrioventricular discordance. The RV (systemic chamber) is more hypertrophied than the LV. 