[1] Kangwon Natl Univ, Sch Med, Dept Internal Med, Div Cardiol, Chunchon, South Korea
[2] Kosin Univ, Gospel Hosp, Dept Internal Med, Div Cardiol, Busan, South Korea
[3] Univ Ulsan, Coll Med, Ulsan Univ Hosp, Dept Cardiol, 877 Bangeojinsunhwando Ro, Ulsan 44033, South Korea
[4] East Lancashire Hosp NHS Trust, Blackburn, Lancs, England
[5] Seoul Natl Univ Hosp, Dept Internal Med, Seoul, South Korea
[6] Seoul Natl Univ Hosp, Ctr Cardiovasc, Seoul, South Korea