At the conclusion of this activity, the participant should be able to: 

• Perform a thorough clinical investigation for a congenital atrial septal defect when seeing an unexplained large right atrium and right ventricle.
• Calculate flows through the right ventricle and left ventricle outflow to exclude a significant left to right shunt.
• Determine whether additional congenital heart defects are present, after identifying an initial one using cardiac magnetic resonance imaging (CMR).
• Decide when utilization of CMR or transesophageal echocardiogram (TEE) is appropriate to confirm suspected presence of sinus venosus defects.
• Recognize atrial arrhythmias as common in patients with atrial septal defects, both before and after repair.