1. College of Health Sciences, Qatar University, Doha P.O. Box 2713, Qatar
2. Qatar Computing Research Institute, Hamad Bin Khalifa University, Doha P.O. Box 5825, Qatar
3. Department of Cardiology, Al-Khor Hospital, Hamad Medical Corporation, Doha P.O. Box 3050, Qatar
4. Heart Hospital, Hamad Medical Corporation, Doha P.O. Box 3050, Qatar
5. Division of Cardiology, Department of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA