1. From the Oxford Heart Centre, Oxford, UK (S.W., A.P.B., S.S., D.W.P., X.Y.J., P.A.C., D.R., N.M., A.K.); National Heart and Lung Institute, London, UK (P.A.P.-W.); Jarvik Heart Inc, New York, NY (R.J.); and Texas Heart Institute, Houston (O.H.F.).