[1] Kings Coll London, BHF Ctr Excellence, Div Cardiovasc, London SE1 7EH, England
[2] Liverpool Heart & Chest Hosp, Liverpool, Merseyside, England
[3] Royal Brompton Hosp, Clin Trials & Evaluat Unit, London SW3 6LY, England
[4] Birmingham Heartlands Hosp, Birmingham B9 5ST, W Midlands, England
[5] Leeds Teaching Hosp, Leeds, W Yorkshire, England
[6] Brighton & Sussex Univ Hosp, Brighton, E Sussex, England