1. From the University of Birmingham Institute for Cardiovascular Sciences, City Hospital, United Kingdom (M.M., E.S., D.A.L., M.P., G.Y.H.L.); Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Centre for Heart Diseases, Zabrze, Poland (M.M.); and Division of Family Practice, Chilliwack General Hospital, British Columbia, Canada (A.W.).