1. From the Department of Electrophysiology, Heart Center, Ghent University Hospital, Ghent, Belgium (M.E.H., R.S., F.V.H., M.D.); Cardiology Unit, Applied Biomedical Systems, Maastricht, The Netherlands (R.H.); and Department of Cardiology, Sint-Jan Hospital Bruges, Bruges, Belgium (R.T., M.D.).