1. Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (S.P.J., J.L.C., K.J.M., L.H.N., R.-A.N.T.O.).
2. Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (N.A.B.).
3. Geisinger Health, Danville, PA (A.R.C.).
4. Loyola University Medical Center, Maywood, IL (K.A.G.).
5. University of North Carolina at Chapel Hill, NC (A.H., R.V.).
6. University of Texas Southwestern Medical Center, Dallas (W.V.).