1. Department of Cardiology, Texas Heart Institute, Houston (M.W.S.).
2. Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas (N.K., S.R., S.R.D., A.P.).
3. Parkland Health and Hospital System, Dallas (N.K., S.R., S.R.D., A.P.).
4. Division of Cardiology, University of California Los Angeles School of Medicine (G.C.F.).