1. Cardiovascular Division, Faculty of Medicine, Tsukuba University, Ibaraki, Japan (A.K.T., S.A., E.S., Y.K., K.K., T.K., X.D., K.T., M.I., H.Y., N.M., Y.S., A.N., K.A.).
2. Division of Cardiac Arrhythmia, Cardiovascular Center, Kansai Medical University Medical Center, Osaka, Japan (M.T.).
3. Himeji Cardiovascular Center, Japan (A.S., K.O.).
4. Department of Cardiology, Yokohama Minami Kyosai Hospital, Japan (M.N.).
5. Cardiovascular Division, Saitama Red Cross Hospital, Japan (T.H., J.N.).
6. Division of Cardiology, Gunma Prefectural Cardiovascular Center, Maebashi, Japan (M.K., K.K.).
7. Tohoku University Graduate School of Medicine, Sendai, Japan (M.N., K.F.).
8. Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (S.K., K.K.).
9. Cardiology Department, Tokyo Metropolitan Bokutoh Hospital, Japan (Y.Y.).
10. Department of Cardiology, Asahikawa Medical University, Hokkaido, Japan (A.T., N.S., Y.K., N.H.).