Andrew R Houghton MA(Oxon), DM FRCP(Lond), FRCP (Glasg) Consultant Cardiologist Grantham et District Hospital Grantham, UK and Visiting Cardiologist, University of Lincoln, Lincoln, UK. David Gray DM, MPH, BmedSci, FRCP (Lond), FRIPH Reader in Medicine & Honorary Consultant Physician Department of Cardiovascular Medicine University Hospital, Queen's Medical Center Nottingham, UK.