[1] Portsmouth Hosp NHS Trust, Cardiol, Portsmouth, Hants, England
[2] Univ Med Ctr Utrecht, Julius Ctr Hlth Sci & Primary Care, Utrecht, Netherlands
[3] Univ Hosp Southampton NHS Fdn Trust, Southampton, Hants, England
[4] London Sch Hyg & Trop Med, Fac Publ Hlth & Policy, London, England