There is a lack of echocardiographic studies to address the detection of atrial masses and abnormal venous connections in patients with secundum atrial septal defect (ASD) repair. This study sought to demonstrate that with proper technique, these unusual conditions could be diagnosed confidently by transthoracic echocardiography. We performed a retrospective review of all repaired ASD patients of all ages with follow-up echocardiography done at Beijing Anzhen Hospital from year 1999 to 2005. Clinical and echocardiographic features of patients with aforementioned conditions were evaluated. Systematic echocardiographic protocol identified 11 patients with unusual conditions, in whom four patients had atrial masses (three atrial thrombi, one inflammatory pseudotumor) and seven patients had abnormal venous connections (two inadvertent diversion of inferior vena cava to left atrium, five previously unrecognized partial anomalous pulmonary venous connections). Atrial masses and abnormal venous connections could be diagnosed through a systematic echocardiographic approach in evaluating patients with ASD repair.