1. School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital , London SE1 7EH , UK
2. Department of Cardiology, St Thomas' Hospital , London SE1 7EH , UK
3. Department of Cardiology, Amsterdam University Medical Center , Amsterdam , the Netherlands
4. Gottfried Schatz Research Center, Division of Biophysics, Medical University of Graz , Graz , Austria