[1] Royal Brompton Hosp, London SW3 6NP, 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] Hop Europeen Georges Pompidou, Paris, France
[6] Hop Cardiovasc & Pneumol Louis Pradel, Lyon, France
[7] Herzzentrum Ludwigshafen, Ludwigshafen, Germany
[8] Newcastle Univ, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[9] Adelaide & Meath Inc Natl Childrens Hosp, Dublin, Ireland
[10] Inst Cardiol, Warsaw, Poland
[11] Aarhus Univ Hosp, DK-8000 Aarhus, Denmark
[12] Univ St Radboud, Ctr Med, Nijmegen, Netherlands