1. Cape Heart Institute, Faculty of Health Sciences University of Cape Town Cape Town South Africa
2. Klinik für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universitätsklinikum des Saarlandes Saarland University Hospital Homburg Germany
3. Division of Cardiology, Groote Schuur Hospital, Faculty of Health Sciences University of Cape Town Cape Town South Africa
4. South African Medical Research Council Cape Town South Africa
5. Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences University of Cape Town Cape Town South Africa