1. From the Faculty of Medicine, Al-Quds University, Jerusalem, Palestine
2. Faculty of Medicine, Islamic University of Gaza, Gaza, Palestine
3. Department of Medicine, St George’s University of London, London, United Kingdom
4. Faculty of medicine, Ain shams university, Cairo, Egypt
5. Department of Cardiothoracic Surgery, Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
6. Department of Cardiac and Thoracic Surgery, Heart Center Trier, Trier, Germany.