1. From the Department of Electrophysiology, University Heart Center (D.S., M.F., A.S., H.S., B.A.H., J.L., B.S., S.W., D.S.) and Department of Medical Biometry and Epidemiology (K.W., S.L.), University Hospital Eppendorf, Hamburg, Germany; II Medical Clinic, Department of Electrophysiology, Johannes-Gutenberg University, Mainz (T.R.); and Center for Electrophysiology at Klinikum Links der Weser, Bremen, Germany (I.B.).