1. Harefield Heart Science Centre (E.L.-P., L.E.F., E.J.B., P.S., K.D.P., R.G., M.H.Y., N.R., P.J.R.B.), Royal Brompton and Harefield National Health Service Trust, London UB9 6JH, United Kingdom
2. Mouse Biology Unit (E.L.-P., N.R.), European Molecular Biology Laboratory, 00015 Monterotondo, Italy
3. National Heart and Lung Institute, Imperial College London, and Harefield Hospital (E.J.B., R.G.), Royal Brompton and Harefield National Health Service Trust, London UB9 6JH, United Kingdom
4. Cardiovascular Division (J.L.H.), Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455