1. Cardiovascular Division, Department of Medicine, Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (E.A., E.L., F.M.C.-V., J.W.W., P.J.Z., K.K., A.E.B.).
2. Department of Cardiology, Sint-Jan Hospital Bruges, Belgium (M.D., T.S.).
3. Division of Cardiovascular Medicine, Richard A. and Susan F. Smith Center for Cardiovascular Outcomes Research, Beth Israel Deaconess Medical Center, Boston, MA (C.S.).
4. University of Vermont College of Medicine, Burlington (P.S.S.).
5. Division of Cardiology, Section of Cardiac Electrophysiology and Arrhythmia Service, University of California, San Francisco (A.L., E.P.G.).
6. Biosense Webster, Johnson & Johnson, Research and Development Department, Yokneam, Israel (E.N., M.B.-T.).