1. Division of Cardiovascular Medicine (B.J.C., E.A.L., D.S.P., E.A.S.), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
2. Smith Center for Outcomes Research in Cardiology (B.J.C., J.G., E.A.S.), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
3. Penn Cardiovascular Outcomes, Quality, & Evaluative Research Center, Cardiovascular Medicine Division, Department of Medicine, University of Pennsylvania, Philadelphia (E.A.S.).