Division of Cardiology, Department of Internal Medicine, Kyung Hee University, Seoul, South Korea. Division of Cardiology, Department of Internal Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan. Department of Cardiology, The Fourth Hospital of Harbin Medical University, Harbin, China. Division of Cardiology, Department of Internal Medicine, Kyung Hee University, Seoul, South Korea. Electronic address: kkabeeheart@empal.com. Division of Cardiology, Department of Internal Medicine, Kyung Hee University, Seoul, South Korea. Electronic address: mylovekw@hanmail.neet.