1. Second Department of Propaedeutic Internal Medicine, Medical School, Aristotle University of Thessaloniki, Hippocration Hospital, Thessaloniki, Greece
2. Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
3. First Cardiology Clinic, National and Kapodistrian University of Athens, Hippokration Hospital, Athens, Greece
4. Department of Clinical Biochemistry, Royal Free Hospital Campus, University College London Medical School, University College London (UCL), London, UK