1. From Stanford University School of Medicine, Stanford, California.
2. Requests for Reprints: Ruey J. Sung, MD, Cardiac Electrophysiology and Arrhythmia Service, Stanford University Hospital, Room H2146, 300 Pasteur Drive, Stanford, CA 94305.
3. Grant Support: Dr. Tan was supported by the Netherlands Heart Foundation (Grant R93314) and the Durrer Fund Netherlands. Dr. Hou was supported by the MacKay Memorial Hospital, Taipei, Taiwan.