[1] Royal Brompton & Harefield NHS Trust, London, England
[2] London Sch Hyg & Trop Med, London WC1, England
[3] Hosp Univ Gregorio Maranon, Madrid, Spain
[4] Policlin San Matteo, I-27100 Pavia, Italy
[5] Erasmus MC, Thoraxctr, Rotterdam, Netherlands
[6] Hop Europeen Georges Pompidou, Paris, France
[7] Hop Cardiovasc & Pneumol Louis Pradel, Lyon, France
[8] Herzzentrum Luwigshafen, Ludwigshafen, Germany
[9] Newcastle Univ, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[10] Adelaide & Meath Inc Natl Childrens Hosp, Dublin, Ireland
[11] Inst Cardiol, Warsaw, Poland
[12] Aarhus Univ Hosp, DK-8000 Aarhus, Denmark
[13] Radboud Univ Nijmegen Med Ctr, Nijmegen, Netherlands