Institution: | 1. Division of Cardiology, Department of Medicine, John Cochran Veterans Affairs Medical Center, St Louis University School of Medicine, St Louis, Missouri USA;2. Division of Cardiology, Department of Medicine,University of Colorado, Aurora, Colorado USA;3. Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington USA;4. Division of Cardiothoracic Surgery, Department of Surgery, University of Colorado, Aurora, Colorado USA |