Heterotaxy: Right atrial isomerism with AV canal defect

A transthoracic apical four chamber in a patient with right atrial isomerism demonstrating an L-looped ventricle, as the left ventricle (LV) is on the right side of the patient and the right ventricle (RV) is on the left side of the patient. A complete atrioventricular (AV) canal defect is also noted with the very large atrial septal defect (ASD) and large, inlet ventricular septal defect (VSD). There is no true tricuspid or mitral valve. Instead, a common atrioventricular valve (CAVV) is shown, which supplies equal flow to each ventricular mass, consistent with a relatively balanced complete atrioventricular canal.