title: Author's reply.
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan. Electronic address: asato@md.tsukuba.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Sato
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kawabe
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma