1. Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Yonsei University Health System , 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752 ,
2. Institute for Innovation in Digital Healthcare, Yonsei University , Seoul ,
3. Division of Cardiology, Department of Internal Medicine, Korea University Medical Center, Korea University Anam Hospital , 126-1 Anam-5ga Seungbuk-ku, Seoul 136-705 ,