1 Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, 306 Lyons-Harrison Research Building, 701 19th Street South, Birmingham, AL, 35294-0007, USA. proctor@uab.edu.
2 Section of Cardiology, Birmingham Veterans Affairs Medical Center, Birmingham, AL, USA. proctor@uab.edu.
3 Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, 306 Lyons-Harrison Research Building, 701 19th Street South, Birmingham, AL, 35294-0007, USA.
4 Section of Cardiology, Birmingham Veterans Affairs Medical Center, Birmingham, AL, USA.