1. From the Department of Cardiology, Na Homolce Hospital, Prague, Czech Republic (P.N., J.P.); Cardiac Arrhythmia Service, Mount Sinai School of Medicine, New York, NY (V.Y.R.); Department of Cardiology, Institute for Clinical & Experimental Medicine (IKEM), Prague, Czech Republic (J.K., D.W.); Hopital Universitaire Geneve, Geneve, Switzerland (D.S.); Endosense SA, Geneva, Switzerland (H.L., A.Y.); and Abt Kardiologie, Asklepios Klinik St. Georg, Hamburg, Germany (E.W., K.-H.K.).