1. From the Clinical Pharmacology Unit and Research Centre, University of Edinburgh, Western General Hospital (D.E.N., C.L., D.J.W.), and the Departments of Cardiology (D.E.N., R.A.W., C.L., K.A.A.F., N.A.B.) and Haematology (C.A.L.), University of Edinburgh, Royal Infirmary, Edinburgh, Scotland, UK. Dr Wright is now at the Department of Cardiology, The Ayr Hospital, Ayr, Scotland, UK.