1. From the Division of Cardiac Surgery, Cardiology, Biostatistics, Asan Medical Center, College of Medicine, University of Ulsan (D.-H.K., J.H.R., S.-C.Y., D.-H.K., J.-M.S., S.J.C., J.-K.S., J.-W.L.), and Samsung Medical Center, Sungkyunkwan University School of Medicine (S.-J.P., S.W.P., P.-W.P.), Seoul, Korea.