The morphology of the various types of interatrial communications has been known since the early description by Rokitansky,1 but the clinical diagnosis was not described until 1941.2 Hospital mortality after surgical repair of atrial septal defects during the early years was about 3%3 and for many years it has been less than 1%, with correspondingly low complication rates. The era of transcatheter closure of secundum atrial septal defects is now well established but confusion reigns regarding ideal occlusion devices and indications for their use. The past and current success of surgery cannot be ignored when evaluating current fashions, and although it is true that routine closure is not of proved benefit to all patients there is a general consensus among cardiologists and surgeons that when an atrial septal defect gives rise to right ventricular dilatation it should be closed. Such defects usually measure 10 mm or more in diameter and occupy one third or more of the length of the atrial septum in echocardiographic four chamber sections.