Cor triatriatum dexter masquerading as Ebstein's anomaly.

We report the case of a child with cor triatriatum dexter masquerading as Ebstein's anomaly on transthoracic echocardiography. This was attributed to a floppy membrane arising from the right atrium, protruding into the tricuspid valve and pushing the leaflets downwards, giving an impression of Ebstein's anomaly. The importance of recognising this pitfall will prevent misdiagnosis of Ebstein's anomaly.