1. From the Cardiovascular Center, Yokosuka Kyosai Hospital, Yokosuka, Japan (M.T., A.T., T.K., K.O., Y.T., Y.W., K.T., T.F., S.K., H.H.); and Clinical Research Center (M.T.), Heart Rhythm Center (K.H.), and Department of Cardiovascular Medicine (M.T., M.I.), Tokyo Medical and Dental University, Tokyo, Japan.