Dr Varnava undertook her medical training at Oxford University and St Bartholomew’s Hospital where she attained triple Honours. She went on to train in cardiology at The Royal Brompton Hospital & St George's Hospital. She is now a consultant cardiologist at St Mary's Hospital, Imperial College and Watford General Hospital, West Herts, where she undertakes general cardiology. Her area of specialist expertise is in the inherited cardiac conditions (cardiomyopathies, channelopathies and sudden cardiac death). Her other areas of specialisation are heart disease in women and through pregnancy. She is also expert in sports cardiology and on the FA advisory panel and cardiologist to many premiership football teams. She regularly lectures at international meetings and has published widely in leading medical journals.