1. From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).