1. Cardiovascular Research Center; Massachusetts General Hospital; Boston MA USA
2. Division of Preventive Medicine; Brigham and Women's Hospital; Boston MA USA
3. Division of Cardiology; London Health Science Center; London ON Canada
4. CardioVascular Institute, Beth Israel Deaconess Medical Center; Boston MA USA
5. Harvard Medical School; Boston MA USA
6. Cardiac Arrhythmia Service; Massachusetts General Hospital; Boston MA USA