1. From the Divisions of Cardiovascular Medicine (M.B.K., H.C.H., J.O., S.A., D.J., R.L., J.G.) and Cardiovascular Surgery (N.D.D., Z.F., J.E.B., W.Y.S., P.V., R.M., D.M.K.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia.