1. Department of Cardiology, Harefield Hospital, Royal Brompton and Harefield Hospitals, Guy’s and St Thomas’ NHS Foundation Trust , Hill End Road, Harefield, UB9 6JH , UK
2. National Heart and Lung Institute, Imperial College London , Harefield Hospital, Hill End Road, UB9 6JH, London , UK
3. College of Engineering, Design and Physical Sciences, Brunel University London , Kingston Lane, Uxbridge, UB8 3PH, UK