We report interesting echocardiographic images of the atrial septum in two growing premature infants related to the previous use of umbilical venous lines in the neonatal period. Complications related to central venous lines are well documented but when they are identified in follow up after several months, their relevance is difficult to establish. Atrial septal findings of organized clot in these asymptomatic infants needs to be correlated with details of neonatal care.