1. Division of Cardiology, Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Carnegie 568, Baltimore, MD 21287, USA
2. The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, 601 N Caroline St, Baltimore, MD 21287, USA
3. Department of Epidemiology, Johns Hopkins University School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA
4. Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205, USA