1. Centre for Clinical Magnetic Resonance Research, Radcliffe Department of Medicine, Division of Cardiovascular Medicine, University of Oxford, Oxford, U.K.
2. Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, U.K.
3. Department of Cardiology, John Radcliffe Hospital, Oxford, U.K.
4. First Department of Cardiology, Aristotle University, Thessaloniki, Greece