Eisenmenger syndrome is the last-stage of congenital heart diseases with untreated left to right shunt. Tolerance and prognosis are better than with idiopathic pulmonary hypertension. However, patients follow-up is often performed in inappropriate non-specialized care centres which makes the collection of epidemiological data difficult. Consequently, population registries are necessary and would increase knowledge of natural history. Finally, complications are often multiple and unexpected with lack of specialized management. Such patients require expert supervision with a multidisciplinary approach in experienced and specialized centres.