[1] Royal Brompton Hosp, Adult Congenital Heart Ctr, London SW3 6NP, England
[2] Royal Brompton Hosp, Ctr Pulm Hypertens, London SW3 6NP, England
[3] Univ London Imperial Coll Sci Technol & Med, Dept Clin Cardiol, Natl Heart & Lung Inst, London, England
[4] Univ London Imperial Coll Sci Technol & Med, Dept Epidemiol & Publ Hlth, London, England
[5] St Marys Hosp, Int Ctr Circulatory Hlth, London, England