1. From the Adult Congenital Heart and Electrophysiology Services (P.K., L.-A.M., P.G.G., J.-P.L., A.D.), Montreal Heart Institute, Montreal, Canada; Boston Adult Congenital Heart and Electrophysiology Services (P.K., M.J.L., S.M.F., E.P.W.), Children’s Hospital, Boston, Mass; the Adult Congenital Heart Unit (M.A.G., A.F.), Royal Brompton Hospital, London, England; the Institut Universitaire de Cardiologie et de Pneumologie (J.-M.C.), Quebec, Canada; and the Cardiology Service (A.F.), Sainte-Justine...