1. From the Division of Cardiology (D.-H. Kim, D.-H. Kang, M.-Z.L., J.-M.S., J.-K.S.), Cardiac Surgery (J.-W.L.), Biostatistics (S.-C.Y.), Asan Medical Center, College of Medicine, University of Ulsan; and Cardiovascular Center (Y.-J.K., D.-W.S.), Seoul National University Hospital, Department of Internal Medicine, Seoul National University College of Medicine, Korea.