1. the Bristol Heart Institute (K.M.S., A.H.B., A.C.N.), University of Bristol, Bristol (UK) Royal Infirmary, and the Departments of Pharmacology (M.F.) and Cardiology (A.P.B., V.J.T., R.P.F., P.H.G.) and the Institute of Nephrology (M.D.), University of Wales College of Medicine, Heath Park Cardiff.