1. Walter Reed National Military Medical Center, Department of Cardiology, Bethesda, MD, United States of America
2. Walter Reed National Military Medical Center, Department of Electrophysiology, Bethesda, MD, United States of America
3. Electrophysiology Section/Duke Center for Atrial Fibrillation, Division of Cardiology, Duke Clinical Research Institute, Department of Medicine, Duke University, Durham, NC, United States of America