Dr Markides trained at St Mary’s Hospital and Imperial College, London, qualifying in 1992 with Honours in all subjects and the University of London Gold Medal. He trained in Cardiology and Cardiac Electrophysiology at a number of London teaching hospitals before being appointed as a Consultant Cardiologist at Royal Brompton & Harefield NHS Foundation Trust in 2003. He led the arrhythmia service there during its rapid growth phase between 2006-2014, and since 2014 has been the Director of the Heart Division at the Royal Brompton Hospital