[1] Univ Exeter, Peninsula Med Sch Primary Care, Exeter EX1 2LU, Devon, England
[2] Plymouth Hosp NHS Trust, Cardiothorac Dept, Plymouth, Devon, England
[3] Peninsula Med Sch Primary Care, Truro, England
[4] Hosp NHS Trust, Dept Cardiol, Birmingham, W Midlands, England
[5] York St John Univ, York, N Yorkshire, England
[6] Univ Exeter, Peninsula Med Sch, Peninsula Technol Assessment Grp, Exeter EX1 2LU, Devon, England
[7] Univ Queensland, Sch Human Movement Studies, Brisbane, Qld, Australia
[8] Univ Birmingham, Dept Publ Hlth Epidemiol & Biostat, Birmingham, W Midlands, England
[9] Univ New England, Sch Sci & Technol, Armidale, NSW, Australia