1. Asklepios Klinik St Georg, Hamburg, Germany (K.-H.K., M.S.).
2. Clinique Pasteur, Toulouse, France (J.-P.A.).
3. Cardioangiologisches Centrum Bethanien, Frankfurt (K.R.J.C.).
4. Universitätsklinikum Düsseldorf (A.F.).
5. Universitätsmedizin, Greifswald, Germany (M.B.).
6. Isala Klinieken, Zwolle, the Netherlands (A.E.).
7. Medtronic, Inc, Minneapolis, MN (K.M.B., F.J.K., L.H.).
8. University Heart Center Freiburg-Bad Krozingen, Germany (T.A.).
9. Heart Rhythm Center at Centro Cardiologico Monzino, IRCCS Department of Clinical Sciences and Community Health, University of Milan, Italy (C.T.).
10. Hospital Clínic de Barcelona, Spain (J.B.).