[1] London Chest Hosp, Barts & London NHS Trust, Dept Cardiol, London E2 9JX, England
[2] Newham HealthCare NHS Trust, Dept Cardiol, London, England
[3] UCL, Rayne Inst, London, England
[4] Barking Havering & Redbridge NHS Trust, Dept Cardiol, Barking, Essex, England