1. From the Departments of Cardiology, Asan Medical Center, (D.-W.P., Y.-H.K., J.-M.A., J.-Y.L., W.-J.K., S.-J.K., S.-W.L., C.W.L., S.-W.P., S.-J.P.), and Division of Biostatistics, Center for Medical Research and Information (S.-C.Y.), University of Ulsan College of Medicine, Seoul, Korea.