1. From the Department of Internal Medicine, Division of Cardiovascular Medicine (B.A.M., A.B.W.), Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine (B.A.C., A.B.W., D.M.S.), and the Dyspnea and Performance Evaluation Center (B.A.M., B.A.C., A.B.W., D.M.S.), Brigham and Women’s Hospital and Harvard Medical School, Boston, MA; and the Department of Cardiology, Veterans Affairs Boston Healthcare System, West Roxbury, MA (B.A.M.).