TODAY the diagnosis of atrial septal defect (ASD) in childhood no longer engenders anxiety or even a sense of urgency. The repair of an uncomplicated ASD is associated with a low and quite generally acceptable mortality.1-4 That there is no aspect of urgency is attributable to a preponderant evidence that ASD is benign in childhood.5-10 Indeed, not only may there be a remarkable longevity associated with this lesion11-16 but the patients attaining such longevity commonly do not demonstrate significant pulmonary hypertension.12-16 This is not to say, however, that a certain morbidity and mortality has not been ascribed to ASD in infancy and childhood. Hastreiter et al10 described 13 cases in which congestive heart failure secondary to ASD was considered the primary cause of death. All of these patients developed a fulminant clinical picture prior to 18 months of age. Only three patients were older than