1. Texas Cardiac Arrhythmia Research Foundation, Austin (A.N.).
2. Johns Hopkins University, Baltimore, MD (H.C.).
3. Arrhythmia Institute at Grandview, Birmingham, AL (J.O.).
4. Florida Hospital Cardiovascular Institute, Orlando (S.J.P.).
5. Minneapolis Heart Institute, MN (D.M.).
6. Hospital of the University of Pennsylvania, Philadelphia (F.E.M.).
7. San Diego Cardiac Center, CA (C.A.A.).
8. Baylor Scott & White Heart and Vascular Hospital, Fort Worth, TX (C.D.).
9. Emory Saint Joseph’s Hospital, Atlanta, GA (A.M.P.).
10. Sentara Cardiovascular Research Institute, Norfolk, VA (P.J.G.).
11. The Heart Hospital Baylor Plano, TX (B.D.).
12. Montreal Heart Institute, QC, Canada (L.M.).
13. Virginia Commonwealth University, Richmond (K.A.E.).
14. Icahn School of Medicine at Mount Sinai, New York, NY (S.R.D., V.Y.R.).
15. Massachusetts General Hospital, Boston (M.M.).