1. From the Department of Medicine (K.C.F., J.Y., F.A.S., D.L., J.M.G., R.J.G.), Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Mass; the Department of Medicine (F.A.S.), McMaster University, Hamilton, Ontario, Canada; and the Department of Medicine (J.E.D., J.S.A.), University of Arizona, School of Health Sciences, Tucson, Ariz.