1. Mayo Clinic Rochester, MN (A.C.E., J.T.P., C.A.W., H.M.C.)
2. Cincinnati Children’s Hospital, OH (S.B., J.R.D., A.T., N.A., G.R.V.)
3. Medical College of Wisconsin, Milwaukee (S.G., M.N.)
4. New Queen Elizabeth Hospital, Birmingham, United Kingdom (P.C.)
5. Emory Adult Congenital Heart Center, Atlanta, GA (B.K., W.M.B.)
6. Golden Jubilee National Hospital, Glasgow, United Kingdom (N.W.)
7. Medisch Spectrum Twente Hospital, Enschede, The Netherlands (L.W.)
8. Phoenix Children’s Hospital, AZ (T.M.)
9. Toronto General Hospital, Canada (E.O.)
10. Indiana University School of Medicine, Indianapolis (W.A.K.)
11. University of Edinburgh, United Kingdom (T.G.-W.)
12. University of Utah and Intermountain Healthcare, Salt Lake City (A.H.).