1 Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina.
2 Duke Clinical Research Institute, Durham, North Carolina.
3 Division of Cardiology, Ahmanson-UCLA Cardiomyopathy Center, University of California Los Angeles Medical Center, Los Angeles, California.
4 Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada; Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada.
5 Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
6 Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
7 Department of Medicine, University of Mississippi, Jackson, Mississippi; Baylor Scott and White Research Institute, Dallas, Texas.
8 Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina; Duke Clinical Research Institute, Durham, North Carolina. Electronic address: stephen.greene@duke.edu.