[1] Univ Manchester, Cardiovasc Inst, Manchester M13 9WL, Lancs, England
[2] Duke Clin Res Inst, Durham, NC USA
[3] Royal Bolton Hosp, Dept Gastroenterol, Farnworth, Lancs, England
[4] Univ Manchester, Inst Populat Hlth, Manchester M13 9WL, Lancs, England
[5] Univ Hosp North Staffordshire, Dept Cardiol, Stoke On Trent, Staffs, England
[6] Univ Wales Hosp, Dept Cardiol, Cardiff CF4 4XW, S Glam, Wales
[7] Khon Kaen Univ, Dept Med, Khon Kaen, Thailand
[8] Queen Elizabeth Hosp, Dept Cardiol, Birmingham B15 2TH, W Midlands, England
[9] James Cook Univ Hosp, Dept Cardiol, Middlesbrough, Cleveland, England