1. From the Division of Arrhythmia and Electrophysiology, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan (T. Kamakura, M.W., I.N., K.I., K.M., H.O., T.N., T.A., H.T., S.Y., H.O., W.S., S.K., K.K.); Division of Cardiology, Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan (T. Kamakura, T.M., T. Kimura); and Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan (W.S.).