Spontaneous closure of a large secundum atrial septal defect

Large and untreated secundum atrial septal defects are closed in childhood in order to prevent significant rates of morbidity and mortality. Small defects often close spontaneously. We present a girl with a large atrial septal defect that underwent spontaneous closure at just over three years of age. The defect was haemodynamically significant and larger than conventional expectations for spontaneous closure.