1. Adult Congenital Heart Centre and Centre for Pulmonary Hypertension, Royal Brompton Hospital, Royal Brompton and Harefield Hospitals, Guy’s and St Thomas’ NHS Foundation Trust , Sydney St, London SW3 6NP , UK
2. National Heart and Lung Institute, Imperial College London , Guy Scadding Building, Dovehouse St, London SW3 6LY , UK
3. Harefield Hospital, Royal Brompton and Harefield Hospitals, Guy’s and St Thomas’ NHS Foundation Trust , Hill End Rd, Harefield, Uxbridge UB9 6JH , UK
4. Adult Congenital Heart Disease Unit, University Hospital 12 de Octubre , Av. de Córdoba, s/n, 28041 Madrid , Spain