1 Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: jmarine2@jhmi.edu.
2 Division of Cardiovascular Medicine, Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Health System, Ann Arbor, Michigan.
3 Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
4 Division of Cardiology, Department of Medicine, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania.
5 Section of Cardiac Electrophysiology, South Denver Cardiology Associates, Littleton, Colorado.
6 Stony Brook Heart Institute, Stony Brook University, Stony Brook, New York.
7 Arrhythmia Center, Piedmont Heart Institute, Atlanta, Georgia.