1. Division of Cardiology; Department of Internal Medicine; Yonsei University College of Medicine; Seoul Korea
2. Division of Cardiology; Gangnam Severance Hospital; Seoul Korea
3. Division of Cardiology; Kangnam Sacred Heart Hospital; Hallym University Medical Center; Seoul Korea
4. Division of Cardiology; Sanggye Paik Hospital; Inje University College of Medicine; Seoul Korea
5. Biostatistics Collaboration Unit; Yonsei University College of Medicine; Seoul Korea