title: Author's reply.
authors.affiliation: Department of Cardiology, Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Wonju College of Medicine, Yonsei University, Wonju, Republic of Korea. Electronic address: yubs@yonsei.ac.kr.
authors.forename: Byung-Su
authors.initials: BS
authors.lastname: Yoo