1 Cape Heart Institute, Faculty of Health Sciences, University of Cape Town, 4th Floor, Chris Barnard Building, Anzio Road, Observatory, 7925 Cape Town, South Africa.
2 Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, South Africa.
3 Klinik für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universitätsklinikum des Saarlandes, Saarland University, Homburg, Germany.