1. Centre for Congenital Heart Diseases, Department of Paediatric Cardiology, Beatrix Children's Hospital; University Medical Centre, University of Groningen; Groningen, The Netherlands
2. Actelion Pharmaceuticals Ltd; Allschwil Switzerland
3. Children's Hospital, Paediatric Cardiology Unit; University of Geneva, Geneva, and Centre Universitaire Romand de Cardiologie et Chirurgie Cardiaque Pédiatriques; Geneva and Lausanne Switzerland
4. Children's Hospital Colorado, Department of Pediatric Cardiology; Denver CO USA
5. M3C-Hospital Necker Enfants Malades, Department of Paediatric Cardiology, Université Paris Descartes; Paris France