1 Adult Congenital Heart Centre and National Centre for Pulmonary Hypertension, Royal Brompton & Harefield Hospitals, Guys and St Thomas' NHS Trust, Sydney Street, London SW3 6NP, UK.
2 Adult Congenital Heart Centre and National Centre for Pulmonary Hypertension, Royal Brompton & Harefield Hospitals, Guys and St Thomas' NHS Trust, Sydney Street, London SW3 6NP, UK; Department of Medical Rehabilitation, Medical Faculty, University of Rijeka, Ul. Braće Branchetta 20/1, Rijeka 51000, Croatia. Electronic address: [email protected].