1 Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, New York, USA.
2 Division of Cardiology, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA.
3 Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA. Electronic address: quentin-youmans@northwestern.edu.