1. Division of Cardiology, University of California, San Francisco (J.T.D., F.N.D.).
2. Department of Cardiac Surgery, Smidt Heart Institute at Cedars-Sinai, Los Angeles, CA (J.C.).
3. Division of Cardiology, New York Presbyterian Columbia Heart Valve Center, Columbia University Medical Center (R.T.H.).
4. Division of Cardiology, Harvard Medical School, Massachusetts General Hospital, Boston (J.W.H.).